1968 in-service training notes - canadian institute of ...€¦ · university of guelph. i safe...
TRANSCRIPT
IIIII
| Papers Presented at the
I EIGHTH ANNUAL
i IN-SERVICE TRAINING COURSEI
FOR PUBLIC HEALTH INSPECTORSI
Sponsored by
I THE ONTARIO BRANCHCANADIAN INSTITUTE OF PUBLIC HEALTH INSPECTORS
ICourse "A" Environmental Pollution - Soil and Water
i April 15-19, 1968
i Course "B" Microbial Aspects of Public Health WithEmphasis on Food Hygiene and Zoonoses
i April 29- May 3, 1968
I UNIVERSITY OF GUELPH
I GUELPH, ONTARIO
II
IIIIIIIIIIIIIIIIIII
!INDEX
l COURSE PAGES"A"
ADDRESS OF WELCOME i
l Dr. H. W. Caldwell, Head, Dept. of ExtensionEducation, Ontario Agricultural College, University
of Guelph.
I SOIL AND WATER POLLUTION 2 - 9Professor L. R. Webber, Dept. of Soil Science,
University of Guelph
I USING SOIL SURVEYS TO PREVENT SOILAND WATER POLLUTION i0 - 14
Professor D. W. Hoffman, Department of Soil Science
l University of Guelph.SOME ASPECTS OF THE FUNCTION OF THE SEPTIC TANK 15 - 20
I Professor R. Johnson, Microbiology Department,University of Guelph.
PRIVATE SEWAGE DISPOSAL SYSTEMS DESIGN, CONSTRUCTION 21 - 24
I & INSTALLATIONProfesSor R. W. irwin, Engineering Science,
University of Guelph.
I SAFE WATER FROM PRIVATE WELLS
Professor F. R. Hore, School of Agricultural 25 - 29
i Engineering, University of Guelph.SOME HYDROLOGIC ASPECTS OF GROUNDWATER CONTAMINATION 30 - 40
Robert W. Gillham, Research Assistant, Department
l of Soil Science, University of Guelph.
SERVICES AVAILABLE FROM OWRC AND THE NEW POLICY ONWATER 41 - 49
l QUALITY OBJECTIVESS. E. Salbach, P. Eng., Program Engineer, Water
Quality Surveys Branch, Ontario Water ResourcesCommission.
J MANURE MANAGEMENT AND UTILIZATION FOR CROPS 50 - 53
Professor T. H. Lane , Department of Soil Science
l University of Guelph.
FERTILIZER USE AND POLLUTION 54 - 63
l Dr. M. H. Miller, Dept. of Soil Science, Universityof Guelph.
LAND DISPOSAL OF WASTES FROM MILK AND CHEESE PLANTs 64 - 71
l Parker, Eng., Consulting Engineer,R. R. e _
Acton, Ontario.
I PESTICIDE MOVEMENT IN SOIL 72 - 75Dr. D. E. Elrich, Dept. of Soil Science,University of Guelph'.
l PESTICIDE PROBLEMS 76 - 82Richard Frank, Provincial Pesticide Residue Testing
i Laboratory Ontario Dept. of Agriculture and Food t
COURSE "B'[ PAGES
MICROBES AND PUBLIC HEALTH 83 - 88'Dr. D. A. Barnum, Chairman, Dept. of Veterinary
Bacteriology, Ontario Veterinary College, •University of Guelph. m
DISINFECTANTS AND MICROBES 89 - 90
Dr. D.A. Barnum, Chairman, Dept. of Veterinary iBacteriology, Ontario Veterinary College,
i
University of Guelph.mm
PRINCIPLES OF FOOD INFECTIONS AND FOOD POISONING OR INTOXICATIONS 91 - 94 i
Dr. D. A. Barnum, Chairman, Dept. of VeterinarY
Bacteriology, Ontario. Veterinary College , •University of Guelph. i
IESCHERICHIA COLI: FRIEND OR FOE OF MAN 95 - 971
Dr. D. A. Barnum, Chairman, Dept. of Veterinary ! •Bacteriology, Ontario Veterinary College,
I
University of Guelph.
LEPTOSPIROSIS 98 iDr. D. A. Barnum, Chairman, Dept. of Veterinary
Bacteriology, Ontario Veterinary College, •University of Guelph. B
BODY RESISTANCE TO MICROBES 99 - i01
Dr. D. G. Ingram, Ontario Veterinary College, iUniversity of Guelph.
SALMONELLA - A CURRENT PROBLEM 102 •
Dr. N. A. Fish, Ontario Veterinary College, gUniversity of Guelph.
CHANGING PATTERNS OF MICROBES 103 i
Dr; N. A. Fish, Ontario Veterinary College,University of Guelph.
m
MEAT-BORNE INFECTIONS 104 - 105 i
Dr. N. A. Fish, OntarioVeterinaryCollege,
Universityof Guelph. D
STAPHYLOCOCCUS- UBIQUITOUSORGANISMOF DISEASE 106Dr. N. A. Fish,Ontario VeterinaryCollege, i
Universityof Guelph. H
REGULATORYCONTROL OF ANIMAL DISEASESOF PUBLIC HEALTH IMPORTANCE 107Dr. N. A. Fish, Ontario Veterinary College, •University of Guelph.
MICROBES AND THEIR ENVIRONMENT 108 i •
Dr. W. R. Mitchell, Ontario Veterinary College, iUniversity of Guelph.
RABIES 109 - 112 H
Dr. W. R. Mitchell, Ontario Veterinary College ,University of Guelph.
!
IN-SERV!CE TRAINING COURSE FOR PUBLIC HEALTH INSPECTORS
1968
UNIVERSITY OF GUELPH
Dr. H. W. Caldwell_ Head, Department of Extension Education_Ontario Agricultural College.
Dr. D. A. Barnum: Chairman_ Department of Veterinary Bacteriology;Ontario Veterinary College.
ONTARIO BRANCH - CANADIAN INSTITUTE OF PUBLIC HEALTH INSPECTORS
President - L. A. Lychowyd C.P.H.I. (C) Canadian National RailwaysPast President -L. I Dodgson_ C.P.H.I. (C): Perth County Health UnitSecretary -J. E, Wood C.P.H.I. (C)_ Simcoe County Health UnitTreasurer - H. W. Schaub C.P.H.I. (C)_ Etobicoke Health Dep,t.Councillors - G. E. Anderson: C. P. S.I.(C) Lambton County Health
Unit
A. S. Hester C.P.H.I.(C), Kent County Health UnitWin. Lloyd C.P.H.I. (C), Lambton County Health UnitJas. Sandul C. P. H. I. (C), Sudbury & District Health UnitJas. M. Watt_ C. P. H. I. (C)_ Renfrew County Health UnitChas. Young_ C.P.H.I.(C) O.W.R.C.Wm. Straughan: C. P. H. I. (C), Simcoe County Health Unit
IN-SERVICE TRAINING COMMITTEE
L. I. Dodgson_ C. P. H. I. (C), Chairman_ Perth County Health UnitA. S. Hester: C. P. H. I. (C): Kent County Health UnitS. C. Cowan_ C.P.H.I. (C), Ontario Department of HealthR. M. Carson_ C.P.H.I.(C), Ontario Department of Health
Ix.
" " " _-_ -:,'- "-"':'T,,o- .. r,_._ _ ,. _L . ,.• . . - . ,
,. - 7._- _-._., _.: .-...-_.. ... ;... . _.' ,;.:':_,
l
i
I PAGES
i MILK BORNE INFECTIONS 113Dr. W. R. Mitchell, Ontario Veterinary College,
University of Guelph.
i A KEY TO FOOD POISONING AND FOOD INFECTION AND ANOUTLINE PROCEDURE FOR THE INVESTIGATION OF A FOOD-BORNE OUTBREAK 114 - 122
Dr. W. R. Mitchell, Ontario Veterinary College,
i University of Guelph.
ONTARIO VETERINARY COLLEGE 123
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I Dr. H. W. Caldwell, Head,Dept. of Extension Education,
i OntarioAgricultural College,University of Guelph.
ADDRESS OFWELCOME
I Once again it is a real pleasure for me to welcome to the University campus the members
of the Ontario Public Health Inspectors to the 8th Annual In-ServiceTraining Session.
! •No doubt you will feel that it.is a kind of reunion, especially for those of you who
have been here for several years° If you have been away.for some time, you will note great-changes - in fact even for those.of you who were_here last year, the campus may look different.
l For example, we have now a newCrop Science_Buildingbeside the Soil Science Building,occupied but not officially opened_ mWe have a new AnimalScience Building onHighway 6
about ready to be occupied and soonofficially opened. The large new Arts Building is now
l in use and I hope you have time during your stay to go to the top floor and look over thesurrounding area. I know of no better place from which to see the University campus and the
surrounding area as.well.
I I might mention a.few changes that.are to come. You will note that a new complex ofresidences are under construction and.it is,hoped theymaybe_ready for September 1968 when
we expect 5,100 students on.campus_,:You may see the beginnings of enlargement for the
l Biology Building which will become,the,Zoology Building and a.new complexwill arise to in-clude Botany, Horticulture andMicrobiology. A new_Engineering Science Building is under
way as well, and plans for remodelling the Dairy,_Science Building to include anew program
I are planned. Your society will be-especially interested in a new Food Science program tobe introduced this fall and a_new,Department of Food Science will be established. A Chairman
for this new program and DePartment will soon be appointed. I know you whose work is so
i closely tied with_keeping._he_quality_ofour food_high-will be interested in the new program.You cannot help but notice the new Library just completed. It is a very modern building
and I hope your program permits you to see inside,. Some of the offices of the Administration
I are being moved into this-building.this week, indeed-the.office of our.new President, Dr. W.C. Winegard. I hope you may get a chance to both see and hear this energetic young man with
leadership qualitiesneeded,bysuch_anexpanding_University.
I I must apologize for any inconvenience this week. The University has made history ofquestionable renown. I believe this is the first time that a strike has been held on our
University campus° We hope,you_are-not too inconveniencedby the situation. '
Again let me say "Welcome". I hope that your course will be interesting and of valueto you in the important work you do in looking after the health of the Nation.
!
!1
!
Professor L.R. Webber, •Dept. of Soil Science,
i
University of Guelph.
SOIL AND WATER POLLUTION i
During the next four days, you wili hear presentations by a number Of speakers. •
We believe these men to be the leaders in their field of specialty and its application to ienvir0mental pollution° They will outline the problem and in many instances provide you
with answers to the problem: how to control or abate pollution of soil and water. In other nproblems,
you will hear about current research in an attempt to find a solution, ii
• There is evidence of growing concern and action programs by Society as they
realize in disgust that we have degraded and befouled resources that our forefathers pre- nsumed would be in supply for all time. For example, at least 30 million people dump their
waste into, and drink from the Great Lakes. •We use inland streams and rivers as handy,
cheap sewers tO carry away our wastes - sewage, industrial chemicals, long-lasting poisons; •and junk ranging from small cans to automobile hulks. |
We are participants in a self-made experiment in applied ecology. We have thrust n
ourselves an environment against which we rebel - intolerable levels of air pollutants, •upon
°contaminated wa•ter, and gross misuse of land resources. Whereas our standard of living,i
said to be among the highest in the world, includes foods that have to be constantly moni-
tored and tested to assure us that the poisons •are below toxic levels, a certain proportion n
of our drinking water has been used previously for domestic or industrial purposes. Somebeaches are polluted to the point where recreation is prohibited. We see and enjoy a mul-
titude of new projects ensuing from our science technology: we also see our standard of •
living in the shadoW of anawful background of pollution.
UKINDS OF POLLUTANTS• , - . .
' / There are many kinds of pollutants, from 'the noise of cackling hens to deadly •poisons; likewise there are various ways of classification° During your course this week, Bthe following three classes will probably include most
i. pollutants that deplete the oxygen supply, such as, sewage wastes, iorganic material, cannery and milk plant wastes,
i
2. pollutants with a fertilizing value when added to bodies of water, nprincipally nitrogenous and phosphatic compounds.
3o pollutants with adverse chemical or biological effects on life,
such as pesticides, heavy metals, material carring harmful bacteria, iand air-borne pollutants.
iSEWAGE AND SEPTIC TANKS
iEarly in the course, we are going to introduce you to the problems of using soil •
as a means of disposing of human wastes. You may have experienced problems with poorlyi
designed or poorly installed septic tanks and weeping tiles. We hope when the course ends
you will appreciate the importance of soil series and types in recommending, designing, ninstalling, and final inspection of sewage systems.
For many years, Society accepted the statement that: The solution to pollution •was dilution. Accordingly, cities dumped wastes into rivers and lakes and allowed the Br_egenerative processes of moving water to degrade the wastes. You know the results - thes_treams and lakes were over-loaded, they did not have enough oxygen to complete the break-
i of the wastes and pollutionwas upon us._ Dilutionof wastes and_waste waters in Streamsdown
and lakes is no longer satisfactory; many wastes alter the balance of life in the waters _
In many communities water is in short supply. On a volume basis (1966) 60 percent of our
l water came from the Great Lakes and 20 from each of and inland surfacepercent groundwater
waters (8).
l Local water supplies have been augmented by programs that re-used and reclaimedwast water. These programs do not have glamorous goals, but in many areas they are or willbe necessary. To many communities it is apparent that the one-time use of water has become
l a luxury which they can no longer afford. Re-use and reclamation are marked departuresfrom the historical concept of water management; pay for the cost of developing a water supply,
use the water once, pay to get rid of it, and, inso doing, often contaminate your own or
other supplies.
Though the thought of deliberately re-using treated waste water may startle the
average person, the practice is growing.
!Pennsylvania Experiment
i In 1962, the Pennsylvania Sanitary Water Board authorized the University to disposeof sewage effluents on certain land sites (2). Theeffluents were low in total solids and
biochemical oxygen demand (B.O.D.) but enriched in fertilizing elements. In 1965, 58 acre-
l inches of waste water were applied in weekly amounts of 2 inches.7
A summary of nutrients applied in the waste and those removed by crops for 1965 is
I given in Table i.
l TABLE i
I Element Amount Applied Crop Removalib/acre Alfalfa Corn
(tons) (bu)
I Nitrate N 72
l Organic N 34 106 284 iiiPhosphorus 87 34 19
I Potassium 252 _ 298 102
I The average composition of water samples from various depths indicated that after3 years of operation and the application of 170 inches of waste water,the renovation capacityof the soil was excellent. At the 4-foot depth the reduction in the concentration of the
l alkyl benzene sulfonates (A.B.S.) was greater than 90 percent; more than 99 percent of thephosphorus was removed; the concentration of nitrates was less (5.5 ppm)_than in a control(untreated area 6.3 ppm).
I In addition to the disposal of partially treated sewage effluents, the researchindicated that:
1. where 2 inches of waste were applied each week, the. ground water recharge
l was equivalent to 80 to 83 percent of the application.2. to operate on a year-round basis, the system must rely on soil absorption
when plant utilization is negligiblE. Combinations of agronomic and for- C
I ested areas would provide the greatest flexibility in the system.3
m
to dispose of the waste from a town of i0,000 people 129 acres I3.
of land were required; equivalent to i million gallons (UoS.)U
per day. One acre-inch is equivalent to 22,600 gallons (Imp.)
!LAKE EUTROPHICATION
• !With an increasing knowledge of the nutrient requirements of aquatic plants,.it is evident that under normal conditions one.or several chemical elements could limit
plant growth. However, in most instances phosphorus and nitrogen are probably the most m
important, especially where eutrophication has been related to man's activities. From the...........•
results of a survey of 17 lakes in southern Wisconsin, Sawyer (6) concluded that nitrogeni
and phosphorus were the two fertilizing elements which regulated the biological productivity
of these lakes, He concluded that a lake showing concentrations in excess of 0.30 ppminorganic nitrogen and 0.01 ppm inorganic phosphorus at the time of spring turnover could be
expected to produce algal blooms of such density as to be classed as a nuisance.
Nell (4) investigated complaints from the residents around Lake Sturgeon, Ontario, Iand found that accumulations along the shore resembling green paint made bathing unpleasant
and produced offensive odours. The drainage from the north included two lakes where no
problems occurred. Water from the south came largely from agricultural land and a river •carrying primary treated sewage. During the period 1948 to 1951, records indicated that 36 I
cattle and one dog had died from algae poisoning. Results from analyses for various chemical
constituents suggested that phosphorus exerted a controlling or limiting influence on the •growth of bluegreen algae. The concentration of total phosphorus in the lake was 0.034,
0.053, and 0.046 ppm for the years 1953 to 1955. The greatest number of algae •present inany year occurred at the end of 1954 in spite of a cool summer and water temperature lessthan 20oc. A practicalmethod of controlling the excessive productivity of the lake wasfound to be available by treating sewage, which entered the lake by a river, from the town
of Lindsay, population i0,000. The soluble phosphate concentration of the river below the
sewage plant averaged almost 0.2 ppm for two years prior to the experimental treatment of Ithe sewage. With treatment the concentration of phosphorus dropped to 0.017 ppm (0.05 ppm
P04). Nell estimated that• treating the town's sewage with alum for phosphate removal repres-
ented an expenditure of $1.20 per capita. I
From a study of the Grand River, 0ntario, Missingham (3) estimated that the
phosphorus contributed to the ri_er from rural areas was approximately 12 pounds per squaremile per year. An amount which did not appear significant when compared to the yearly per •capita contribution of 0.8 pounds of P from sewage effluents. Owen and Johnson (5) re-
viewed the literature•on the yield of phosphorus from agricultural watersheds. In a study
of phosphorus yields_for several streams in the Metropolitan Toronto region, the authors Ireported that•the average yield of phosphorus from three agricultural watersheds was 410
pounds of PO 4 per square mile per year (equivalent to 0.21 P/acre/year). The authorsnoted that this yield could logically be attributed to streambank erosion. Urban watersheds •
contributed on the average 112 poundSof phosphorus per acre per year, largely from sewage |•effluents. From this study the authors reported that the per-capita yield of phosphorus in
sewage ranged between 2 and 2.6 pounds of phosphorus, average 2.2 pounds per year° Harlow
(i) stated that land runoff played a minor role (6 percent) in the contribution of nitrogen •
and phosPhorus to Lake•Erie. The Raisin River Basin, described as mostly farmland with apopulation of 190 people per square mile yielded 0.29 pounds of phosphorus per acre per
year. The yield from the Huron River Basin, with some farmland and a population of 270 peo-pieper square mile, was 0.90 pounds of phosphorus per acre per year.
Verdiun (7) made a study of the changes•in the concentrations of nitrates and •
phosphorus in Lake Erie during the 14-year period, 1948 to 1962. Nitrates increased by 50 |percent whereas phosphate increased by more than 400 percent (Table 2)°
!
I TABLE 2. CHEMICAL CHANGES IN MAUMEE BAY, WESTERN LAKE ERIE
!Constituent Concentration in ppm
l before 1950 1960 - 61Nitrate nitrogen 0.52 0o81
l Soluble phosphorus 0.035 0.148
!Verduin stated that the three important sources of phosphorus were organic matter
i in sewage, phosphorus-containing detergents, and phosphorus in the runoff and drainage fromagricultural lands. An analysis of data from various watersheds indicated that less than
half the phosphorus in surface waters came from agricultural sources. The supply from urban
sewage appeared to represent the major fraction. Detergents could be the most significant
l source of phosphates enriching the water supplies.
l PESTICIDES
Man's ability to survive, clothe and feed himself is directly related to his
l ability to manipulate Nature in his favour such as, 125 bushels corn per acre, better cropvarieties, better livestock feeds, more gains from livestock. The number of farm workers
(now 8 percent of the population) continues to decrease each year; the acreage of improved
land per person has decreased about 50 percent in the past 25 years. In other words, fewer
i workers produce more from fewer acres to feed more people.i
When we think of pesticides it becomes difficult for some people to separate
l fact, fancy, and emotion. They have a few facts; they fancy they know _ii about pesti-cides with the result they get terribly emotional and their ability to reason fades dram-
atically. Consider these facts: an elm tree was sprayed with a few parts per million
(ppm) of DDT to control aphids; the leaves that fell to the ground had 20 to 28 ppm DDT;
l earthworms ate some of the leaves and on analysis ppmhad 403 DDT in their gizzard; robins
ate the worms and those that died had a high DDT content (50-70 ppm). The events in this
food chain illustrate a serious problem with some pesticides. They are biologically con-
l centrated at various points in the chain. We admit gulls have died and contained highlevels of DDT but you cannot say that all dead gulls were poisoned with DDT. They die o_
old age, virus infections, and a host of other causes.
I Finally, on DDT, the average person had about 7 ppm DDT in-his system° Thoseworking in DDT manufacturing plants are known to have had i00 and 200 ppm in their body.
(DDT in milk and technological changes in measuring) (DDT invented in 1948 by M_ller.
I (Switzerland) givenNobel Prize).
To protect our soils, crops, and health from pollution by pesticides we need to
l know:
i. the precise fate of pesticides in soils: absorption: movement; biodegradation.
l 2. the biological accumulations in the food chains.3. the long-term effects on the health of humans and animals.
Eventually, we shall make specific recommendations and issue licenses for the use
I of - done in of Europe. The recommendations will indicate the kind,pesticides now parts
rate, time of application, for specific pests and specific crops. Once the chemical has
done its job on a particular pest it will degrade to harmless levels in the soil and leave
! 5
no toxic compounds behind° (Apply Aldrin on roots, vegetables and silage, converts to ndieldrin).
When livestock are fed crops treated with dieldrin, the animals tend to store •the insecticide in the fatty tissue. By the process of biological magnification, the animal |tissue may accumulate dieldrin above acceptable tolerance levels. In surveys across Canada
and Ontario, the data indicate that under normal feeding practices the danger of food products m
containing excessive amounts is not likely to cause concern. Cull root crops grown on con- •
taminated land should never be fed to animals nor should sugar beets be grown on land con-i
taining significant dieldrin residues.m
Dro R. C. Harris at Ontario Pollution Conference said: Pesticides are with us l
to stay. Their assets greatly outweigh their liabilities. We must simply learn how to use
them properly and how to regulate and control their use. i
ANIMAL WASTES
Where lovestock, including poultry, is reared under high-density confinement I
housing, the disposal of large volumes of manure is a management problem of growing im-
portance. The manure must be moved from the housing area. The waste generated by the •livestock population in southern Ontario creates a disposal problem equivalent to a humanpopulation of 45 to 50 million people°
a year ago, a committee on the utilization of animal wastes was formed at IAbout
the University of Guelph. The members of the committee include_personnel from Guelphm
(Agriculture and Veterinary Science), University of Toronto, Ontario Water Resources
Commission, Ontario Department of Health, and the Ontario Department of Agriculture and nFood.
The approach and philosophy underlying the current and projected research of this •
committee may be stated as: in the scheme of life almost all the compounds that come from |a living process must be returned to the cycle to build, repair, or provide energy for other
formSoOf life. Thus, livestock manures should be recycled by returning the waste to the nland and
by growing appropriatecrops for efficient utilization of the by-producto l
The treatment and the disposal of animal wastes are complicated problems for
agriculture° Compared with municipal sewage, animal wastes are highly concentrated° It is Inot economically feasible for a farmer_ to _dilute, lagoon, and remove the chemical elements
before discharging the waste to a waterway as is done, in part, with sewage. At Guelph,
our research is oriented to the approach that land disposal is the most feasible means _f- •disposal. |
The Committee on the Utilization of Animal Wastes released a publication which idetailed the land requirements for the utilization of animal wastes in crop productiono |Throughout the publication, emphasis is placed on the _itrogen economy; phosphorus and
potassium ar_ not considered as potential pollutants. In terms of nitrogen we recommend
a maximum of 300 pounds of nitrogen per acre on corn or hay-pasture mixtures° It has been Iestablished that this quantity of nitrogen willbe used by crops and not contaminate the gground water.
Obnoxious odours develop when organic material undergoes anaerobic decomposition.The offensive odours usually contain compounds of sulphur, particularly hydrogen sulphide andnumerous other gases with unique properties injurious to the health of humans and animals. into
Intensive research at the University of Guelph and with cooperating farmers is based on a •very simple principle: reverse the anaerobic decomposition making it aerobic by the
i
incorporation of air to increase the oxygen content of the waste. Our major activity is
to develop new machanical processes or modify existing techniques that would increase the mefficiency of incorporating more oxygen in the waste. Aerobic degestion of municipal wastes
is an accepted and successful procedure because the wastes are highly diluted. An enterprise
involving 30,000 layers or 2,O00 hogs - this is a small farming operation - has a waste-disposalproblem equivalent to a town of 4,000 people. We are confident that our research staff will
l develoP mechanical devices that aerate the concentrated waste, reduce the od0ur problem, andprovide a waste that may be spread on land with a minimum hazard to environmental pollution.
When the Air Pollution Control Act (1967) becomes operative farmers may be liable
i for environmental pollution.(Law of Nuisance - basic that neighbour enjoy his !and) '
l (Who was there first - not relevant - neighbour comes to the nuisance)
(Good intentions and scientific farming not adequate defence)
!SEPTIC TANK EFFLUENTS
l The effluents from septic tanks are discharged into soil by means of field tiles.Under proper soil conditions - depth, texture, drainage and absence of impervious strata -
bacterial action renovates the waste without causing soil pollution or health hazards. It
l is that aerobic conditions exist in soil if the effluent is to be properly treated.necessary a
Obviously the renovating capacity of a soil increases with the depth of a well - drained soilo
I Its is an established fact that coarse sands and gravelly soils serve only asmechanical filters and permit contaminated water to move through. The percolation rate of
clay soils is normally tO6 slow for adequate disposal systems. A soil must retain the effluent
l long enough to permit soil microorganisms to complete the microbial decomposition of the waste,to facilitate the adsorption by the soil of specific chemical ions and the utilization by
plants of many compounds.
l The extensive use of phosphate-base detergents in soaps (2.5 pounds per capita peryear) tends to impair soil permeability, induce soil clogging, and generally reduce the
effectiveness of soil as a disposal medium for septic tank effluents.
l The excessive enrichment of ground and surface waters has been erroneously attri-
buted to the agricultural industry. Studies in Southern Ontario show conclusively that
l domestic sewage contributes more phosphorus to surface waters than the drainage from agricul-tural land. Annual yields of phosphorus varied between I00 pounds per square mile from an
agricultural watershed near Toronto and 8,000 per square mile from a heavily urbanized area.Data from one well-service watershed indicated that approximately 90 percent of the yield of
l phosphorus was directed through the treatment facility.
Overloaded and poorly designed septic systems and particularly the installation
l in wholly unacceptable soil conditions have lead to soil pollution and outbreaks of infectioushuman diseases. To solve the problems associated with the proper disposal of human sewage,
we need only apply intelligently the technology now available and enforce the Public Health
l Act°
SOLID WASTES
!The disposal of solid wastes from the home and from industry is frequently one of
I the major causes of environmental pollution. It is virtually impossible to separate disposalproblems as related to soil, air and water. The disposal of solid wastes by landfill oper-
ations must be considered interms of land pollution.
! Sanitary landfilling is perhaps the least expensive disposal method in use today,
if you make a short-term appraisal, ToO Often, "sanitary landfills" are open dumps - near_ideal conditions for flies, rats and other disease-carrying pests as well as smokeand foul
I odours. 7
I
It is a well-established fact that decomposition takes place in the dumps_ Prod-
of this decomposition are potential hazards to the pollution of soil water and ground water.
To avoid this hazard, the selection of sites must be based on a detailed and'careful apprai-
sal of soil type andgeological formations. It is essential that the site be entirely separ- Iated from any source of ground water. g
......_ We see high-temperature composting of mostsolid wastes including household garbage •
and sewage sludge as an acceptable means of ultimate disposal. At the moment, the greateruse of composting techniques is:delayed until the economics of the procedure have been detailed.
Agricultural land wouldprofit by the use of composted wastes provided the product is avail- 1
able at no cost. A farmer realizes that the compost has no fertilizer value - it is largely |Organic in nature and tO maintain a proper carbon-nitr6gen ratio ifi the soil, he faces aftexpenditure inmore chemical, fertilizers.
We urge municipalities to investigate the future of composting as a solution towaste management. The agricultural industry can be persuaded to use the by-producto Rela_
tively little research is needed to answer the problems in using a compost produced by a •high-temperature process°
We have the technology to advance waste management beyond the garbage pail and Ihome incinerator level. It would appear that society will be motivated to authorize better |waste management practices only when public health is threatened Agriculture has a majorrole in utilizing composted material.
!SUMMARY
To a lesser degree, soils contribute to environmental pollution; to a greaterdegreesoils are the victims of pollution by man. As of now, soil pollution hazards existlargely because of the almost-frantic efforts of man to get rid of his wastes, Soils and I
gr0undwaters have been polluted by inadequate disposal systems for human sewage, industrialM
wastes, :and in isolated instances by livestock reared under high-density housing. Agricul-tural is not guilty of the gross pol!ution of water by phosphorus. Situations exist where •
an agricultural activity may have contributed to above-normal levels of nitrogen in theground water.
There are townships considering legislation that would require the exclusion of Iall livestock rearing enterprises. Generally, these are the communities where the farm
operation was in the country and the absence of land-use zoning programs, ineffective
municipal ordinances, and our society's desire to live in suburbia, have threatened the I
existence of the farm which was established first but had no protection from being engulfed1
by suburbia.
• |REFERENCES CITED
!1. Harlow, George L. 1966. Major sources of nutrients for algal growth in western Lake Erie°
Univ. of Nichigan, Great Lakes Rest. Div. Pub. 15: 389-394.
2. Kardos, Louis T. 1966. Waste water renovation by the land - a living filter, in I
Agriculture and the Quality of Our Environment, p.241-250o A.A.A.S. Pub_-85o
3. Missingham, G.A. 1967o Occurrence of phosphates in surface waters and some related pro- Iblems. J. Am. Water Works Assoc,, 59: 183-211o
control of unnatural fertilization of lake waters. I4.Neii _
John H. 1957. Problems and
Twelfth Indent° Waste Confo, Purdue University.
I
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i 5. Owen, G.E. and M.G. Johnson. 1966. Significanc e of some factors affecting yields ofphosphorus from several Lake Ontario watersheds. Univ. of Michigan, Great LakesRes. Div. Pub. 15: 400-410.
I 6. Sawyer, C.N. 1947o Fertilization of lakes by agricultural and urban drainage J. NewEngland Water Works Assoc. 61: 109-127.
I 7. Verduin, Jacob. 1966. Eutrophication and agriculture in the United States° In Agri-culture and the Quality of Our Environment, p. 163-172. AAAS, Pub° 85.
I 8. Webber, L.R. Water-we have it; we use it; we abuse it.Topic-Jan. -Feb. 1968,
l
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iProfessor D.W. Hoffman, •Department of Soil Science,
i
University of Guelph.
!USING .SOIL SURVEYS_O,PREVENTS0[L AND WATER POLLUTION
Soil surveys are inventories that can be used for all kinds of development of '' isoil resources. Soil survey'_eports contain information about the soils of a region includ-ing characteristics of slope, stoniness, drainage, permeability, texture, structure and organ- i
ic matter content. They also contain soil maps which show the location and extent of each kind •of soil. Only a few years ago the main users of soil survey were people connected with agri-
i
culture because it was thought that the soil's main function was to produce crops. But in
addition to producing crops soils support buildings, airportsand roads, and absorb wastes,and now urban uses are replacing agricultural uses for soils in many parts of Southern Ontario.
How Soil Surveys Are Made HJ
Soil scientists making a soil map examine the soil profile. The soil profileconsists of layers or horizons more or less parallel with the surface of the earth and the
surveyor observes and records everything that might affect the use of the soii. He also imeasures the external characteristics of the soils especially slope, stoniness and erosion.
i
Using airphotos as a base map the soil scientist walks over the area being surveyed and drawsin the lines separating one kind of soil from another. The position of the lines is checked iby digging with a probe or a spade to depths of three feet or more and the characteristics
of the various layers that make up the soil profile are noted. In this way soil maps are
prepared which show the location of the different kinds of soils. •i
There are two kinds of soil maps in Ontario which differ in the amount of de-
tail shown. Until recently most of our soil maps were published at a scale of one inch to
the mile and soil areas of down to twenty acres were shown. More detailed maps at a scale Hof four inches to the mile are now being prepared which show contrasting soil areas down to ltwo acres in size. Smaller areas are shown by symbols but the soil boundaries are omitted.
The accuracy of both kinds Of maps is limited by soil complexity, detail of examination, •
scale of the map and the skill and experience of the mapper. In general the detailed soil |survey maps are about ninety percent accurate while those of the less detailed reconnai-
ssance soil surveys are sixty-five to eighty per cent accurate. Indeed the more recent of Ithese maps have less than twenty-five per cent error and most of the time commonly included iareas are usually closely related.
Soil surveys can be interpreted for many purposes. From a soil map separate Hmaps can be made to show only one soil characteristic such _s relief, drainage, water table,
texture, stoniness, or permeability. These single-factor maps show suitability of sol'is :
for such uses as septic tank seepage fields, waste disposal pits or reservoirs and lagoons. •Of course these maps also show the suitability of soil for a host of other uses but we are |chiefly concerned with those uses which may lead to soil and water pollution.
Use of Soils as Disposal Fields for Septic Tanks i
Because many new homes in rural areas are far from existing sewage lines, septictanks and a system for disposing of effluent are needed. The success or failure of the sewer
system used by most rural dwellers depends largely on the type of soil. At present the feas-ibility of septic tank systems is determined by the results of field percolation tests; Such
tests are made by digging holes to specific depths, filling them with water, and measuring •the rate of fall under saturated conditions. This procedure is time consuming and_laborious iand in addition fails to show certain limitations to septic tank use such as a high water
!lo I
l table which may not be detected by percolation test taken during the dry periods of the year.Correlation of percolation rates with different mapped soil areas can afford a more_accurate •
estimate of the efficiency of a site for waste disposal.
l Before a site is selected as a disposal field, the soil should be closely examined°Important characteristics that affect the functioning of disposal fields are water table,
l hazard of flooding, depth to bedrock or to a lithologic discontinuity, texture, permeability,and slope. If groundwater rises to the level of the subsurface _ilein the filtering field,
the soil is so saturated that it will not take liquid sewage, or effluent, from the septic
i tank. The effluent may rise to the surface of the ground, give off an ill-smelling odour,and endanger health. During the wettest periods, the water table should be at least four feetbe!ow the surface in a subsurface filter field and four feet below the floor of a seepage
pit. Generally, welldrained soils are satisfactory for these disposal systems and poorly
i drained soils are not.
A disposal system for septic tanks should never be on a flood plain or near a
l stream that is likely to flood. In many areas local regulations require that the filter fieldbe located at least fifty feet from a stream, lake, open ditch or other water course into
which unfiltered and contaminated effluent might enter and spread. But fifty feet is an
i arbitrarily selected distance. Research is needed to determine whether or not this is a re-quirement for all soils or whether greater distance between filter field and water-body shouldbe recommended.
l Bedrock should be at least four feet below the bottom of the trenches, the floorof the seepage bed, or the bottom of a seepage pit so that there is enough soil to filter and
purify the effluent. Even more depth is needed if the domestic water supply comes from wells
l and the bedrock is limestone. Limestone has many cracks and unfiltered water may seep intothe domestic water supply if the soil is not deep enough. Also, a greater depth is needed
if the underlying material is sand and gravel. A disposal system works very well in a sandysoil but where the supply of domestic water comes from a shallow source effluent may con-
I the water.taminate
The rate effluent moves through a soil depends partly on the texture of the subsoil
l and underlying material. Water moves faster through coarse, textured sandy and gravelly soilsthan through fine-textured clayey soils. In aneffective system the permeability of the soilshould be moderate to rapid and the rate of percolation should be at least one inch per hour.
l The soil should be tested if there is any doubt about the percolation rate.If other characteristics of a soil are favorable for the functioning of filter
fields slopes up to ten per cent are permissible. Filter beds are easier to construct and
l than they are in steeper places° In rolling areasmaintain in level areas or on gentle slopes
the effluent may follow th'e natural drainage lines through the soil or seep out to the surfacebefore it is properly filtered. Tile Lines for the system should be placed on the contour
I tO assist in filtering the effluent.
In summary then the best soils for septic tank, lagoon, sanitary landfill and other
l types of waste disposal are those that:i. Have a low water table and are well drained.
I 2. Have bedrock more than four feet below the bottom of the seepage trench or pit.
3. Are permeable
I 4. ° Do not have slopes greater than ten per cent
i Information about soil texture, permeability, soil drainage, depth to bedrock or other un-conforming layer, slope and stoniness is given in most soil reports and on soil maps. As
mentioned previously it would be helpful to correlate percolation rates with major soils of
i an area. The results could be extrapolated to other areas of similar soils°ii
• iA percolation test has'been proposed in New York State as standard procedure forevaluating soil areas for sewage disposal _ (3) Percolation test measurements can be conven-
iently made with the floating yard stick assembly shown in figure i. The reasons forl a slow
percolation test can usually be found by referring to the soil descriptions in thesoil sur- ivey report. Alternative treatments for waste disposal in slowly permeable soils may involve
drainage, fill or excavation, construction of diversion terraces above filter beds9 removal
of restrictive hardpans or bedrock, enlargement of seepage field area and other special modi- ifications of the soil. B
Soil surveys are not proposed as a cure for all problems of waste disposal i But
when the data from the survey are properly interpreted pollution from waste disposa! canbe Breduced considerably. i
!IiiIIIiiI
' I
•' i
i
I
I oYard stick
! -Reference stick _. Soil surface
I - /I I
__ _ Hole augered ordug in soil
! -N
! °_- Nails
I Falling
water _ '?_ Tin can
I level m
I
I .Figure i. Floating yardstick assembly used to measure rate of
water'level drop in the percolation test. Taken from
"Using Soil Surveys for Problems of Expanding Population
I in New York State" (3).13
BIBLIOGRAPHY I
Ii. Klingebiel A.A., 1967. Know the Soil You Build On,
Agric. Info. Bull 320, S.C,S._ U.S.D.A.
2. Obenshain S.S., Porter H.C. and Devereaux R.E., 1962. iSoil Survey for Urban Planning and Other Uses,Virginia Agric. Expt. Sta, Blacksburg, Virg.
3. Olson G.W,, 1964. Using Soil Surveys for Problems of the IExpanding Population in New York State.
Cornell Ext. Bull 1123, N.Y. College of Agric. I
I
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_4 |
m
Professor R. Johnson,
....... Microbiology Department,
l Universityof Guelph.
SOME ASPECTSOF THE FUNCTIONOF THE SEPTIC TANK
l Introduction:
l To begin I would like to emphasize'that the septic •tank itself is not the method ofwaste disposal but is an important' part of a system which permits us to dispose Of wasteliquid into the soil.- •
I A safe method of disposal Of all human and•domesticwastes is essential to protectthe family and the community from a potential health hazard and also to prevent the
development ofnuisances. Many diseases•such as typhoid fever, dysentery and various types
l of diarrhoea may be transmitted from one person to another through fecal contamination Offood and water. Such contamination is largely due to the improper disposal of human wastes.
i When a septic tank and tile drainage bed are properly constructed and located, andwhere soil conditions are suitable the potential hazards of human wastes should be effec-tively overcome.
I Function of Septic Tanks:The tank itself has three functions.
l i. Retentionof Solids.
As the sewage entersthe tank the solidmaterial hasan opportunity to settle.
l There is not a continuous flow. Because of this and_suitable construction, settling shouldoccur. It •is quite likely that material of lower specific gravity will also be present "
and will rise to thesurface to•become a••part of the so-called scum or surface layer.
l These solids, settled or scum, are held in the tank. At the same time clarified
effluent is discharged toward_the soil area, ....•
l 2. Biological Activity ....
The solids now present in the tank•are acted upon by bacteria. The bacteria present
l are of such a nature that they Can•thrive under the_conditions<existing. Undoubtedlythere are a variety of bacteria present•but one common •characteristic to all is their ' "ability to grow and carry on their life processes-under,anaerobic conditions. I would
l like to delay a more detailed and intimate consideration of the bacterial activity for afew minutes. We will proceed in a general way and then return to this point.
I 3. Storage ........The sludge and scum continue to accumulate. At the same time biological activity is
taking place.
l The sludge volume will be constantly reduced by_the_packing action of accumulating
sludge and by the.continuous biological!activity. This_will apply, although not to the
i same extent, to the accumulating surface material.i H0weverno matter how rapid orefficient thebiological process a residue of relatively inert solid material will remain.
For these reasons - storage of fresh sludge, time for biological activity, and storage of •
i digested sludge - the tank must be of sufficient size.
l 15
)
When the amount of sludge and scum becomes sufficiently great some of this mater-
ial may leave the tank, build up in the distribution system and eventually clog this system.
!Location: r
Assuming a water tight tank the exact location of this portion of the system is .probably dependent more on servicing than as a possible source of contamination, However thereis always the chance that leakage of joints or even leakage from the tank itself could occur, iNto
It is therefore desirable to locate tanks where any such mishap would not likely contaminate ,
a well, or spring or surface water. Furthermore the inevitable cleaning operation may be am
source of soil contamination and it would be desirable to have this somewhat removed from the
water source area. •
|i
It is the location of" the field tile drainage bed relative to water source which
is very important. Underground contamination certainly can and does occur. The risk of Ieffluent, including micro-organisms, gaining entrance to a water source will depend 6n a |number of factors:
i) Volume Of liquid being processed. _ m2) Nature of the soil.
3) Position of the water table. This could be radically
influenced by the time Of the year or climatic Conditions. •4) Size of the distribution bed. |5) Location of the water source.
6) Construction of the well.
!Although one generally thinks that a disposal system located on lower ground will
not contaminate water sources on higher ground, this is not necessarily so. The usual rela-
tionshi p here is to'have a disposal system near the Soil surface while the bottom Oflthe well 1
on the same property may De much lower. Therefore the drainage from such a bed could con- mceivably move down to the water bearing layer and contamination could move to the well. This
effect could be even worse with a so called drainage pit or cess-pool type installation. •Horizontal as well as vertical distance is necessary for protection. |
Removal of Bacteria: I
Sewage material is subject to biological attack in the tank. Undoubtedly many
organisms which enter will not leave the tank as such. However there is an excellen_ op- •
portunity for the survival of bacteria including pathogenic types. These can be in the liquid mphase and accordingly can pass out with the effluent. Septic tanks should not be considered
as a means of removing bacteria. It follows therefore, that septic tank effluents cannot be •
considered safe from a health viewpoint, i |
The effluent is also objectionable because of its septic and malordor0us nature. •
Field Tile Drainage Bed:
The.soil provides an opportunity.for additional treatment with respect to 'the dis-solved material and bacteria. It will act as a filter to permit water to pass and retain
microorganisms. At the same time organisms present in the soil will degrade orgafiic matter •to simple end products. |
The pathogenic bacteria will die Off in time because 0f unsatisfactory envlron-mental conditions such as reduced temperatures and lack of suitable food material. •
16
I Chemicals:
The normal use of ordinary_ household chemicals will not likely exert an unde-
• sirable e£fect on the physical, chemical, or biological •nature of the tank or tile bed.
l These would include lye, chlorine bleaches, soaps, synthetic detergents, or drain cleaners.If large amounts of a particular fluid are being discarded then the possibility of adverse
effects shouldbe considered. In some cases it would be difficult to give a definite answer.
| 'Usually some other disposal prodedure could be used when in doubt.
In connection with the additives which have been suggested and sold for use with
I septic tanks the following quotation from a publication of the United States Public HealthService may be of interest "some 1200 products, many containing enzymes have been placed on
the market for use in septic tanks, and extravagant claims have been made for some. As far
I as is known, however, none has been proved of advantage'in properly controlled tests."
Biological Activity:
R Fresh sewage solids consist of various proportions of fats, carbohydrates and pro-
teins. Studies have shown that there are variations in the percentages of these different
l ingredients of raw sludge. In addition there are seasonal variations in the composition ofraw sludge. The total activity of many types of bacteria will bring about a digestion and _decrease these three groups of organic matter.
I beginning I under 'Biological Activity' that the bacteria activeIn the mentioned
in a septic tank had, as a common• characteristic, the ability•to grow and carry on their life •processes under anaerobic conditions. Since this is an important characteristic of the •
l environment I would like to establish its influence. If a relatively large amount of oxygenis present in an•environment then aerobic and facultative types could grow and be active. •In an environment without oxygen strictly anaerobic and facultative bacteria •could flourish.
l It is apparent then that there are three groups of bacteria according to their oxygenrequirements. At each extreme are a few species which apparently live best either where
there is no oxygen (anaerobic) or where oxygen is near satuaration (aerobic). Most bacteria
will fall in between and are considered facultative with respect to oxygen tension (or amount
I oxygen Oxidation-reduction reactions_by are ameans energy trans-of present). bacteria of
formation. These reactions, in the absence of oxygen, are completed by the transfer of •
electrons and the release of energy as a result of enzymatic activity. The enzyme s are
l derived from the living cells.
Enzymes are the organic catalysts•produced by living cells but act more or less
i independent of the cell. Chemically enzymes are proteins or associated with proteins. Theyare generally very specific in their action. An enzyme which will split one compound willnot attack another. Sucrase splits sucrose to glucose and fructose but will not touch
lactose. Urease is specific for urea. Different enzymes may produce different materials
E are both intracellular enzymes and extracellular enzymes.from the same substrate. There
The former act upon material capable of passing into the bacterial cell. The latter are
responsible for activity on material whose molecules are too large to pass through the cellmembrane Q
Digestion of the raw sludge involves liquefaction, gasification, hydrolysis and
i humification. Liquefaction implies a change from solid to a liquid phase and involvesextracellular enzymes. Gasification implies action upon dissolved materials. HydrQ!ysisinvolves the action whereby water is added•to a complex molecule and results in a break-
down to more simple molecules. •This can take place both on sludge particles and on dis-
l solved substances. Humification is the conversion of the original putrescibleorganic
matter into a stable innocuous black product consisting of slowly decomposing organicresidues.
I If then sewage sludge is kept at atmospheric •temperature it undergoes rapid change.The organic matter present in the sludge forms an abundant supply of food for the bacteria
i and other microorganisms which are always present in the sludge. Dissolved oxygen is quickly17
utilized and anaerobic decomposition proceeds. Over a prolonged period of time complexorganic compounds are decomposed into simple compounds which are either soluble or gaseous
and the more resistant organic matter remains as humus. _ •I |
Having reached this condition, the sludge contains the bacteria and enzymes which
serve to inoculate the raw sewagein order that the process may proceed without evidence iof successive cycles of events. |
Following are some particular activities of a biological nature which can be expect-
ed to occur.
Decomposition of Carbohydrates: i
Large Polysaccharide molecules such as cellulose or .starch are broken down by iextracellular enzymes secreted.by the organisms involved. Starch is broken down by Sheenzyme amylase to maltose, . Amylase is produced by a variety of anaerobic or-facultative m
organisms present in the tank. •J
Cellulose decomposition is brought about by the elaboration of the enzyme cell_lase;This is a hydrolytic action which converts cellulose to cellobi0se. This can then be •broken down to a glucose.
Probably most of the sugar becomes evident as glucose at som/ time, although others •
(fructose, mannose) may be involved. A great_variety of end products may result from the |anaerobic bacterial fermentation of sugars. These linclude alcohols, organic acids, carbon
dioxide and methane. The particular products formed will depend upon the microorganisms
!present, the pH, temperature and oxidation-reduction potential.
The purpose of this elaborate mechanism is to secure energy for the growth and
activities of the bacteria. • •
Decomposition of Lipides (Fats):
hydrolyzed tO glycerol and fatty acid by lipases. IFats are
Decomposition of Organic Nitrogen:
Raw Sewage contains organic nitrogenous compounds mainly in the form of urea, holdproteins, andvarious.proteins, and variousproducts of protein.degradation. The:general
scheme of enzymatic protein breakdown proceeds through the following steps: •
Protein--_Proteoses----_Peptones==_Peptides_=_Amino Acids
I IComparatively few organisms are.capable of excreting enzymes, known as proteinaSes.which
attack the wholeprotein. A few.members of the genus Clostridium as well as some-membersof the genera Pseudomonas, Proteus, Bacillus are capable.
All bacteria require a nitrogen source. Many utilize an organic source such as the I
amino acids derived from protein. Bacteria decompose amino acids in several ways produc-
ing a variety of end product s, Under anaerobic conditions the changes in pr6teinand_pro - i
tein derivatives result in the formation of some rather odoriferous compounds Some_of |the end products are methyl mercaptans, amines, organic acids, phenol, alcohols, hydrogensulfide, ammonia, carbon dioxideand methane. Some of these will accumulate in the environ-
ment, others may be eventually oxidized to more0stable compounds. Oxidation in the absence •of oxygen has been indicated previously.
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I Methane Fermentation:
Because this pathway of organic matter breakdown is an _portant one in the de-
I gradation of organicmatter under anaerobic conditions in nature and because it also playsan important part in the artificial environments established by man for the alteration of
organic matter I would taqe a moment to describe ito Such activity undoubtedly occurs in
I bottom deposits of rivers, lakes, ponds and swamps as well as lagoons, septic tanks anddigestors. It is, of course, greatly accelerated under the condition of elevated and con-
trolled temperature existing in digestors.
I Organic matter, such as is present in a septic tank, can be converted to methaneand carbon dioxide. The first step involves the hydrolysis previously mentioned, followed
by activity of the so called acid producing bacteria° Several bacterial types will be in-
I volved and will result in the production of alcohols, hydrogen, and fatty acids such asformic, propionic, butyric and acetic. The strictly anaerobic methane-producing bacteria
can produce methane from these simple organic compounds. Each species, and there are eight
I known, has specific requirements and can ferment only a relatively restricted group of theseorganic compounds. Probably several species would be required for the complete methane fer-mentation of some substrates. It is usually considered that methane is produced from twomajor sources :
I Enzymes(i) CO2 reduction: CO2 + 8H > CH4 + 2H20.
Enzymes
I (2) Acetic Acid fermentation: CH3COOH > CH4 + CO2.
Tile Drainage Bed:
I The effluent to the tile drainage bed will have in it dissolved material and micro-
organismS. Many of these microorganisms will die very quickly in the soil environment. The
I dissolved material will be effectively changed by the action of microorganisms in the soilto stable end products such as carbon dioxide, water and the cells of microorganisms.
I ORGANIC MATTER
CARBON OXYGEN HYDROGEN NITROGEN SULPHUR
I I /,TAN-K
I / / \I METHANE CARBON HYDROGEN AMMONIA WATER
DIOXIDE SULPHIDE
i END PRODUCTS OF DIGESTIONAbove is a diagramatic presentation of the conversion of orga_c matter to
the final byproducts of digestion. This involves both anaerobic and aerobic activities,
I these are illustrated below:
I\
I 19
!A. Anaero_c Metaboli _ _ _ B
i of
• i
: Organic Matter l
BACTERIA BACTERIA i l/ _ (NEW CELLS) • (NEW CELLS)
MATTER . ' "° ' I- _ _ \ • . _
• ! |
_-- : J_ PRODUCTS OF
PRODUCTS OF BACTERIAL ," _ BACTERIAL ACTIVITY IACTIVITY. . _ METHANE; CARBON
ACIDS, ALCOHOLS, ETC. f . . DIOXIDE
!B. Aerobic Metabolism _ I
of
Orga_ c Matter I
_ ' _ BACTERIA I(NEW CELLS)
ORG_tiCNATTERoxYGEN _.
ORGANISMS J
PRODUCTS OF
BACTERIAL ACTIVITY.
CARBON DIOXIDE, WATER lAMMONIA.
20 i
i Professor R.W. Irwin,Engineering Science,
i University of Guelph,
PRIVATE SEWAGE DISPOSAL SYSTEMS
l DESIGN, CONSTRUCTION & INSTALLATION
BUILDING SEWER
l - Purpose to carry sewage from the building to the septic tank.Specified by O.W.R.C. Plumbing Regualtions.
l - Characteristics - watertight- root proof joints
- Alignment as straight as possible.
- Slope of sewer - minimum of 1/4 in. per ft.
l - Size - minimum Of 4 in.- Material - cast iron
- concrete
I - vitrified clay- bituminized fibre- asbestos cement
I - p.v.c, plastic- non-ferrousmetal
i LOCATION OF SEPTIC TANK AND FIELD- Downgrade from any water supply.- Minimum of 50 ft. from any water supply on lot or adjoining lots.
l - Minimum of i0 ft. from a lot line.- Minimum of 5 ft. from a building foundation.- Minimum depth of 4 ft. of soil above rock or watertable.
l - Do not place on filled soil.- Complete grading and levelling of lot prior to installation.- Beware of tree roots which may affect absorption field.
- Do not place field Under trafficways where frost goes deeper.
l SEPTIC TANK
l - Purpose- hold sewage while digestion takes place.
- allow larg e particles to settle to bottom and digest slowly and leaves
l a sludge.- digests some suspended solids and forms a scum on surface.
i - Requirements- depth to accept sewage by gravity flow from the building sewer.- minimum cover of 6 in. of soil.
- watertight
l - minimum depth of liquid of 4 ft.- removeabla top or access holes of 24 in.
- keep out floor drainage, downspouts and foundation drainage.
l SIZE OF TANK
- depends on daily amount of sewage.
I per person per_ 6 0 gals. day.
- minimum of 500 gals. retained in tank.
l 21
- Length of time retained. •- 24 hrs. preferably 36 hrs.
am
- length of time can be reduced for very large tanks.
- Space for sludge storage, i- minimum of 6 cu. ft. per person.
- See Table 1 for recommended dimensions.
!Table 1 Recommended Dimensions for.Septic Tanks
No. of Max. No. of TANK SIZE RECOMMENDE_ DIMENSIONS B
Bedrooms Persons Without With Inside Inside Liquid Totali
Served Garbage Garbage Width Length Depth Depth
Disposal Disposal IUnit Unit
Ft. In. Ft. In. Ft. In. Ft. In. l
Less 2 4 500 3-0 7-0 4-0 5-0
" 2 4 720 3-3 8-0 4-0 5-0
" 3 6 600 3-0 8-0 4-0 5-0 •
" 3 6 900 3-6 9-0 4-6 5-6" 4 8 720 3-3 8-0 4-0 5-0
" 4 8 i,i00 4-0 i0-0 4-6 5-6 •
" 5 i0 900 3-6 9-0 4-6 5-6 |" 5 i0 1,300 4-0 12-0 4-6 5-6
|
SHAPE OF TANK p
- Shape,when of equal capacity,does not materiallyaffect the operationof the tank.- If over 500 gal. capacity, should be rectangular. _ •- Length not less than 2 nor more than 4 times the width. |- If length over 8 ft., divide into 2 compartments, first is 2/3 total capacity and
second is 1/3 total capacity, more efficient in removing solids. n
- increase size by 50 percent if garbage disposal units used. (These do not increase n
sewage flow materially but tank must handle increased amount of sewage solids.) Min.I
size tank 750 gals.
MATERIAL n
, 6" 8" •- Cast-in-place concrete use - walls, reinforced.
- Precast high stress concrete, mQre likely to be watertight than one poured on the 1site, examinefor cracks. "_\ !
- Metal, 12 ga. asphalt coated steel to prevent corrosion,short life 5-10 years, am
(often bought too small due to low cost of small sizes and then require frequent •cleaning).
1
- Fibreglass reinforced polyster resin, lightweight, usually circular in shape.
- Concrete blocks on slab floor, coat inside with asphalt. 1- Plywood treated with asphalt.
INLET PIPE
- 4 in. tee or baffle, from building sewer, vertical, to carry sewage downwardinto tank.
- bottom of tee or baffle 6" - 9" below water level but not below bottom of outlet, n
- Inlet 3 in. above outlet to allow gases to escape through vent in building plumbing.
Direct venting of tank reduces temperature and slows action. Backwater is preventedand the stranding of solids in the building sewer. •
22 •
I OUTLET PIPE- 4 in. verticaltee or baffle with bottom submerged35-40 percent of total liquid depth,
to prevent scum and solids from passing into drainage field.
SYPHON CHAMBER
I - high cost generally not justified for average system.- bell and automatic syphon operates by air pressure and gravity flow.
- 3 in. syphon generally adequate but should be designed.
- syphon system useful when field over 500 ft. to improve performance of disposal field
I better distribution and less chance of freezing.by
- field should be adequate to hold volume discharge and fill tile 2/3 full so spread
over entire area, not just trickle close to tank
I EFFLUENTSEWER AND HEADER
I - same specifications as for building sewer.DISTRIBUTION BOX
I - to provide equal flow to each lateral tile line.purpose
- size generally 2 ft. x 2 ft.- seldom achieves uniform distribution expected of them.
l ABSORPTION FIELD
i - how long and how wel! a private sewage disposal system will work depends largely onthe soil,
-soil characteristics determined by the Percolation test. While this test is the basis
for design, it is rather unreliable particularly when the percolation capacity is low.
I These are the soils where failures usually occur therfore the design is rather criti-cal. _- percolationtests should give the area of seepage surfacerequired. The layout is
l then planned.- pattern dependson topography,shape of property and length of drain. If slopingground then lay on contour. _ •
l - above ground filters used for rock areas or high water table, farms only.- conventional type of field has drain tile or pipe laid in trenches.
- seepage bed may be a satisfactory substitute for conventional trenches, operateson same principle but does not disperse the effluent over as large an area,
I Excavate entire area, lay gravel, lay pipe in a looped system, cover with gravelthen lay tar paper, newspaper or polyethylene to prevent soil goinginto the gravel.- most economical system is a cross system - root proof header with laterals at right
i angles across the header, header is 2 in. above the laterals to improve distributionof effluent.
- construction details of absorption field.
- maximum length of laterals 60 ft.
I laterals should be ofequal length.
- slope of laterals 2-4 in. per i00 ft.
- end caps on each lateral, if independant,
I - drain tile should be laid with 1/4 to 1/2 in. spaces.- perforated pipe should Be laid with holes down.
- drain tile should be provided with temporary cover of tar paper or newspaper
I until gravel cover stabilizes.- 12 in. of crushed stone, clean washed graded gravel 1/2 in. to 2 1/2 in. orslag placed in bottom of trench.
- install the tile or pipe on this gravel bed.
l - with 3 in. of clean gravel.cover pipe
- in clay soils the depth of gravel base is increased and the tile are not as
deep.
B ...... 23
- place a layer of newspaper or polyethylene on gravel. •° 12 in. Of top soil Covers gravel and temporary cover.
minimum number of Laterals i 2. i
separate Laterals by 3 times width of trench, minimum Of 6 ft. •i
-Table 2 gives details for trench spacing and total seepage area required.
Table 2. Recommended Sizes for Disposal Field Trenches _I B•i
Type of Minutes for Lineal Feet of Trench Req'd Minimum '_ DSoi_l Water to _Fall For Bedroom Effective _ i
i" Width Width Width Width Area in
in Test Hole 18" 24" 30" 36" Sq. Ft. •Depth Depth Depth Depth18 -30 18 -30 18-20 24 -36
Gravel 2 33 25' 20 -17 50
3 _ 40 30 24 20 60
4 47 35 28 23 70 •
i
Sand 5 .53 40 32 27 80
i0 _ 67 50 40 33 i00
sandy iLoam 15 87 65 52 43 130Sandy ....
Clay 30 120 90 72 60 180 iClay 60 160 120 96 80 240* '_ •
60 Require special, des$$n filteri
Min. spacing between •
trenches in ft. 6 6 7 1/2 9 Bi
M_in. Trench Lengths
per dwelling 2-50' 2-38' 2-30' 2-25 ' •i
Not less 150 sq. ft. Total (i00 ft. of 18 in. trench)am _
MAINTENANCE I
- annual inspection. •- clean when sludge & scum = 1/3 liquid capacity. i- frequent cleaning may not guarantee long useful life as solids carried
over into tile and clog openings. i
- service available to clean tank but not maintain field ii
PROBLEMS DUE TO"mm
- tank too small, i
-poor layout of field.
- careless construction, i
n-inadequate disposal area.- lack of maintenance.
-high water table.
!
IProfessor F.R, Hore,
School of AgriculturalEngineering,
University of Guelph.
i
Safe Water from Private Wells
!. .. . Man'sincreased activity on the surface of the earth and his concentration into•co.unities accentuates the growing need for careful reassessment of the sanitary requirements
I for private water supplies° An indication of the in this ofsanitary problem sector our so-
ciety is given in a 1946-60 survey of the incidence of wauerborne disease outbreaks in the
United States (i)_ The survey showed that over twice as many outbreaks occurred in private
I or_sem_-public water systems than in public utility systems. Whereas half the outbreaks in-• volv_ng public utility systems were associated with contamination of the collection and dis-
tributionsystem, over three quarters of the outbreaks involving private or semi-public
i ystems were associated with contamination of the source of supply. Untreated groundwater •was the chief source responsible for these outbreaks° Inadequacies in survey data particu_
larly amongst private Users are recognized so that the problem is probably worse than indi-
catedo. However, it does appear obvious that groundwater supplies should not be looked upon
I t0_day as being assuredly safe supplies as they sometimes have been in the past.
A distinction should be made between two possible types of polluted groundwater.
I A deep groundwater source of pure water may become polluted due to local surface contaminationin the immediate Vicinity Of the well. Proper construction of the well and the water supply
piping system will guard against this type of pollution. On the other hand, a shallow
i groundwater source is much more susceptible to gross pollution (for example, due to floodingwith polluted water from time to time) which may affect large portions Of the groundwater
body. If deeper safe supplies do not exist and such a source must be used, treatment tocontinuously purify the supplies will be required. Essentially, these readily polluted
I sources, which include groundwater in fissured limestone exposed to the surface, should belooked upon and treated the same as any other surface water source.
l This paper summarizes both construction and treatment practices to provide potablegroundwater supplies, some of these suggested practices are already covered in existing
ProvincialRegulations such as the Plumbing Code, 1961, Regulation 471 of the Ontario Water
I. Resources.Commissiono
_i) Weibel, S.R., FoR. Dixon _and R.Bo Weidnero Waterborne-disease outbreaks
i 1946-60 Journal of the American Water Works Association.56:8, pp 947-958, Aug. 1964.
I Well Construction
Choose a convenient location to simplify installation of the supply system but
I locate the well ground than the decrease the chance ofon higher surrounding area to con-
tamination from a septic tank system, barnyard, or surface runoff. A nautral or artificialslope away from the well should exist to prevent retention of surface water within a
I 50 foot radius of the wello A well on a side hill should have an interceptor ditch 50 feetaway on the uphill side. A well should be located at least 50 feet away from any source ofpollution.
I The well casing should be made of new material with watertight joints extendingat least i0 feet below the surface° Where a source of pollution exists within 50 to i00 feet
of the well, a minimum of 25 feet of watertight casing should be used° New casing is spe-
I cified as old have harmful contaminants imbedded in thecasing may walls; watertight joints
are required to preVent the entry of near-surface water which may be contaminated.
I 25
iImmediately surrounding the well casing , mound the soil several inches and extend •
the well casing at least one foot above this level to prevent entry of surface water into thei
well.i
The annular space around the outside of the well casing should be filled with i
cement grout or clay a minimum distance of i0 feet below the surface° This practice will pre-
vent surface or near-surface contaminated water from accumulating and passing downward into •
deeper uncontaminated groundwater. HOn a drilled well with steel casing,• a pitless adapter should be used to provide i
a watertight seal at the point where the pipe(s) from the pumping equipment enter the well. •With other types of casing material, a cement grout joint covered with a waterproofing com-pound makes an effective seal.
i
The top end of the well casing should be capped with a vented cover to allow i
access to pipes and pumping equipment yet discourage tampering by people especially children.
The upper end of the vent pipe (minimum 1/4 inch diameter) should be bent downward and cover- •
ed with a screen to prevent entry of insects and other foreign matter. Commercial sanitary iwell caps are available for steel well casings; raised concrete covers will provide protec-tion for other types Of casing material.
The final steps in well construction are to pump the well until all turbid water i
is removed and the water runs clear and then disinfect the well with a strong chlorine solu-
tion. Pollution and possible harmful bacteria are introduced into the well during construc- •tion and also any time the well is opened for repair or maintenance. Procedures for dis- Hinfection are outlined later°
i
Supply System Construction B
All pipe material and connections in the water supply system must be watertight Bto avoid the introduction of any foreign matter or contaminated water into the potable water
system. The use of pitless adapters where the system pipes join the well was covered under i
• well construction° ii
New pipe should beused; do not install pipe that has been used for anypurpose
other than the distribution of potable water° B4
For maximum sanitary protection, pipes should be kept under pressure at all times
to prevent contaminated water from being sucked into the system. The suction pipe leading •underground from the well to an offset location of the pressure system, is vulnerable to icontamination. This situation can be avoided by running the suction pipe Concentrically
inside a protective pipe pressurized by water from the pressure system. Inadequate sized
pipes in the distribution system could also lead at times to conditions where a vacuum will •occur in part of the system. This is the type of condition that generally occurs in a
public utility system when the system does become contaminated. The best protectivemeasure
to avoid this condition is to ensure that adequate sized pipes are installed throughout •the system.
To avoid contaminated water from entering the system at the pump, locate the •pressure system in a clean, dry, house basement or a specially built above-ground pump ihouse. The installation of the pressure system in a below-ground pit is not recommended due
to the danger of flooding and the continuous moist conditions which hasten corrosion and i
deterioration of equipment, ii
Finally, the system should be flushed, pressure tested and checked for l_aks,
and disinfected with a strong chlorine solution. "_ Bi
, 26 i
Disinfection of Wells and Supply System
I _ New or repaired wells should be disinfected thoroughly because they may be con-taminated from the equipment, material, or surface water that may be introduced. It is also
recommended that the complete water supply system be disinfected at the same time.
I.To disinfect a well, first estimate the number of gallons of water in the well.
For every i00 gallons, mix 16 ounces of household laundry bleach,(5%) with 5 gallons of water
I to make a strong chlorine solution. Run the required amount of solution into the well througha hose or pipe as it is alternately raised and lowered; this will help mix the solution
with the well water. Wash the exterior parts of the pump drop pipe with the chlorine solu-
i tion as it is being placed in the well, Start the pressure system and open all faucets onthe water supply system until a strong odor of chlorine is noticed. Close all faucets and,• ifpossible, attach a hose to one faucet and re-circulate the water back into the well for
about an hour washing down the interior wall of the well casing. Allow the chlorine solu-
f tion to remain for at least eight hours and then run the water to waste until all traces ofchlorine are removed.
l Have a bacteriological test made and if coliforms are still present, repeat theabove chlorination procedure. If the test again is positive, investigate the area in an
attempt to locate and remove the source of pollution. If the source of pollution cannot
l be found and removed, an alternate source should be considered, or, the water should be con-tinuously disinfected with a chlorination system.
I Continuous Disinfection With Chlorine
If well water of doubtful safety must be used, continuous disinfection with
I chlorine will be required. Small automatic chlorinator units are available which are in-stalled in conjunction with the pressure system to add a controlled amount of chlorine solu-
tion to the water when the pump operates.
l The accepted recommendation for chlorine treatment of water is the appli-widely
cation of sufficient chlorine to maintain a residual chlorine concentration of 0.5 to 1.0 mg/l
after a 15-minute contact period. The practice of simply installing a chlorinator unit on
I a conventional pressure system will not ensure that a 15-minute contact period will beachieved; during peak periods of demand, chlorinated water will short circuit through the
pressure tank and may possSbly reach a faucet in less time than the reqfiired 15-minute contact
l period.Hence, an alternate chlorination technique called, "superchlOrination", should be
used. Superchlorination involves the addition of a greater quality of chlorine which leaves
I a higher residual and reduces considerably the contact period required to kill organisms.It is known that some contact time is required to kill harmful organisms and the actual
amount of contact time depends upon,
I (a) the concentration of the injected chlorine(b) the water temperature
i (c) the pH of the waterTherefore, for a water of given pH and temperature, the contact time required will varywith chlorine concentration. A practical method of achieving this shorter contact period
l is to pass the chlorinated water through a large coil of plastic pipe installed in thedistribution line. Chlorine is added automatically at the pump.
l Willrich (2) outlined a design method to determine the length of pipe (contactpipe coil') required. It is first necessary to determine
I 27
.... i(2) Willrich, T.L. Design of a chlorination-dechlorination system for water disinfection.
Unpublished ASAE Paper No. NA63-503, presented at ASAE Meeting, 0rono, Maine,
August 1963.D
the required contact time which dan be computed using the disinfection equation,
Ct = K •
where, C is the chlorine residualin mg/l.t is the contact time for disinfection in minutes. i
K is a constant for a given organism, water temperature and pH. From disinfection Idata for various organisms , Willrich developed Table 1 which allows the selection of.an appro-
u
priate K value for water with different temperatur e and pH values. A desirable chlorine
!residual from 1 to 5 mg/1 (practical values are from 3 to 5 mg/1) is selected and the re-quired contact time is computed,
Knowing the contact time required, the length of the contact pipe coil can be •computed from the equation, |
Pipe length (feet) = 34 x contact time (mins.) x Flow rate (U_S. _pm) l• (pipe diameter in inchesi 2 I
Studies have shown that a practical pipe diameter is between 1 1/4 to 2 inches. Table 2 Ishows the required length of i I/2-inch diameter pipe for different flow rates and requiredcontact times.
Table i. K values for Disinfection by Superchlorination (2) l
Maximum Lowest Expected-Water Temperature •
Expected pH
50 ° for warmer 40 ° for lower
7.0-7.5 8 12 I7.5-8.0 15 20
8.0-8.5 20 30
8.5-9.0 22 35 I
Table 2. Length_ in feet_ of 1 i/2-inch Plastic Contact Pipe Coil I
Requi redContact Flow rate (U.S. gpm) B
Time, min. 2 5 i 8 i0 i'2 15 20 30 I
° 1 30 75 ' 120 150 180 225 300 450
2 60 150 240 300 360 450 6003 90 225 360 450 540
!4 120 300 480 600
5 • 150 375 600
l Example
Well water - lowest expected temperature of 38°F.
I - pH 7.2- maximum flow rate of i0 U.S. gpm
From Table i, K is 12
lJ Select a chlorine residual of 4 mg/l; hence C = 4K 12
Contact time, t = _ = _- = 3 minutes.
I rom Table 2, the length of 1 1/2 inch pipe required to give a contact time of 3 minutesat a flow rate of i0 U.S. gpm is 450 feet.
I For many purposes, water with a high chlorine residual up to 5 mg/l can beused. However, for drinking and cooking purposes, a part of the chlorinated water can be
dechlorinated by passing it through an activated carbon filter unit.
I
lIII
II
I
I
lRobert W. Gillham,
Research Assistant,
Dept. of Soil Science, i
• Universityof Guel)h. l
Some Hydrologic Aspects of Groundwater Contamination i
It has been estimated that one million cubic miles, or over 95% of the world's •
fresh water is present as groundwater. In Ontario, excluding "the large metropolitan areas |bordering the Great Lakes, many municipal and most rural water supplies are from groundwater.
As the population increases, accompanied by a decrease in the quantity and quality of;surface
supplies, increased demands will be placed upon the groundwater reservoir; thereforel, it is l
imperative that the capacity of this reservoir not be reduced by unnecessary contamination.mm
Of even greater significance at the present time is the threat imposed On existing_water sup-
plies by the spread of contaminated zones of groundwater. _ l
A report by the United States Geological Survey on groundwater contamination
inMichigan outlines cases of contamination resulting from the disposal of a diversity of •substances at or near the ground surface. Biological contamination was attributed to;septic |tanks, leaking sewers, sanitary land fills, barnyards and lagoons, Instances of chemicalcontamination resulted from the surface disposal of phenol, fuel oil, creosote, refiDery i
waste, picric acid, chromium, oil-field brines, pickle brines, liquid fertilizer, salt for •snow removal, cyanide and mine waste water. i
In Ontario there has been no survey to determine the extent of groundwater B
contamination; however, isolated instances of contamination by a number of substances _in-
cluding bacteria, nitrates, gasoline and radioactive wastes have been reported.
Various authorities consider the accidental or deliberate disposal of wastes ion or near the ground surface to be the major contributor to groundwater contamlnatlonIt is apparent that a growing problem exists.
The occurrence and extent of contaminated zones of groundwater depend both upon
the chemical nature of the waste material and the geologic and hydrologic conditions Sur-
rounding the disposal site. This paper will consider some of thepertinent hydrologicfactors affecting movement of contaminants through both the unsaturated and saturated zones,with particular emphasis upon the latter.
i
Zone of Aeration l
Contaminants within the zone of aeration remain relatively immobile except Iunder the influence of percolating water. This water may come from precipitation or fromthe disposal of liquid wastes. The rate of percolation and thus the rate of movement
of contaminants is affected primarily by the degree of saturation and texture of the medium. IHigh percolation rates would be experienced in coarse textured materials having a high
moisture content, whereas low rates would occur in a relatively dry clay medium. TheSe are
important considerationswhen determining a suitable location for waste disposal or the
best procedure for the land application of liquid wastes. I
Lateral movement by dispersion in an unsaturated medium is Slight. Thus!the
primary direction of water and contaminant movement is vertically downward. _ i
Zone of Saturation I/
On reaching the zone of saturation, contaminants are carried in thenatural
groundwater flow system. Both the direction and rate of flow are of concern. These can be
30 |
I determined by the application of Darcy's law:
m dHQ = -K_ A
where Q = discharge in ft3/sec; K = hydraulic conductivity in ft/sec; H = hydraulic
l potential in ft.; L = length of the flow path in ft.; and A = cross-sectional area in ft 2.d__His referred to as the hydraulic potential gradient and determines the rate of change ofdL _ potential with distance.
i Hydraulic potential (H)
i Hydraulic potential is an expression of the energy status of the water at anypoint in the flow system. The direction of groundwater movement is along the most directpath from areas of high potential towards areas of lower potential.
I The hydraulic potential at any point in a saturated zone can be determined
by the use of a piezometer (pressure measuring device). The simplest piezometer is an open-
ended pipe. The elevation to which water rises in the pipe (relative to some arbitrarily
l chosen datum) is a measure of the hydraulic potential in the vicinity of the open end _
In natural groundwater flow systems, both vertical and horizontal potentialgradients may be present° In such circumstances a three dimensional flow system is said
l to exist. There is no solution for flowgeneral such systems.
Most groundwater contamination problems occur in shallow, unconfined aquifers,
i (aquifers bounded at the upper surface by a watertable). In such circumstances, providedthe aquifer medium is Of uniform texture, it can frequently be assumed that the direction
of groundwater flow is horizontal. Furthermore, under such circumstances, the watertable
l elevation is a measure of the hydraulic potential, and this potential can be assumed to beuniform throughout the thickness of the aquifer. Provided these assumptions are applicable,
the flow system may be treated as being two dimensional in the plan view, with changes in
the watertable elevation representing changes in potential, and the direction of flow be-
l ng from higher water table elevations towards lower elevations. The slope of the watertable is a measure of the hydraulic potential gradient.
I The water table is frequently assumed to be a subdued replica of the surfacetopography° Higher hydraulic potentials would correspond to topographic highs, thus the
direction of groundwater flow would be in the direction of decreasing surface elevations.
This is frequently true in large areas having a uniform topography; however, in local areas,or areas of irregular topography, the topographic features may have little bearing on the
direction of groundwater flowo
l Hydraulic conductivity (K)
As indicated by Darcy's law, in order to determine the discharge of water
I through a given area, the hydraulic conductivity of the medium as well as the potentialgradient must be known. Hydraulic conductivity is a measure of the permeability of the
medium, or the ease with which a fluid will pass through the medium. It can be defined as
i he volume of water that will pass through a unit cross-section of the medium in unittime under the influence of a unit hydraulic potential gradient.
Both laboratory and field methods have been develope_ for determining (K).
l Field methods usually employ peizometers or holes augered to a depth below the water table.These methods_have the advantage of being fast, relatively inexpensive, and giving a measureof the conductivity in the natural situation.
! Hydraulic conductivity values for unconsolidated materials vary from approx-
imately 104 ft/hr for gravel to i0_4 ft/hr for clayey sands.
!i
Example
The principles discussed previously may be demonstrated by considering alspec- lffic study. The purpose of the study was to determine the quantitative and qualitative con-tribution of a particular barnyard to groundwater contamination, and to determine the:extent
Ofofnitrogenthecontaminated(N)willZOnebeconsidered.Ofgroundwater. ......For illustrative purposes, only the contrlbutlon_ I
In determining the contribution of (N) made by the barnyard to the groundwater,
it was necessary to know the amount of watermoving through the barnyard as well as the_ •
change in the (N) concentration of the water as it passedbeneath the barnyard. MeasUrementsg
of hydraulic conductivity and hydraulic potential, as well as water samples for chemical
analysis were obtained from a network of piezometers and water table observation•wells•in- •
stalled in the regionof,the barnyamd ......The piezometers were constructed of polyvinylehloride i(P.V.C.) pipe having an inside diameter of 0.75 inches° The bOttom 4°5 inches of each pipe
was perforated with fifty-four 0.25-inch holes and covered with 60-mesh brass strainer cloth. •Water table observation wells were constructed by perforating the P.V.Co pipe with two |0.0625-inch holes per inch of length.
Fig. i shows a typical installation, and the distribution of installations over Ithe study area is shown in Fig. 2.
Measurements of the water elevation in the piezometers and water table observa- •tion wells indicated variations in potential from site to site and between piezometers at
the same site. Thus, both lateral and vertical potential gradient s were present° As thelateral movement of nitrogen •from the barnyard in the groundwater was of concern, only thelateral components of potential were considered. The problem was therefore simplified to a •two'dimensional flow System in the horizontal plane: the lateral potential gradient was in-dicated by variations in the water table elevation.
The water table elevations were plotted on a map of the area, and equip0tential l
lines having a potential interval of one foot were drawn. Fig. 2 shows the variation in pom
tential for the conditions of July 5, 1967. Fig. 2 is, in effect, a contour map of the water •table. Since the direction of groundwater flow is at •right angles to lines of equal poten- |tial and in the direction of decreasing potential, it appears that water would move f_om
the vicinity of sites No. 22 and 23, through the barnyard, and out through the cross-section
of sites No. 6,4,5 and 14o I
Analysis of samples from sites Noo 22 and 23 was considered to be representative
of the water before it _assed under the barnyard. The average concentration determined at •
these sites was 2.0 ppm -N. The Concentrations determined at sites NO. 4,5,6 and i4 Were
considered to be representative of the water as it left the barnyard. Fig. 3 is a cross-
section through these four sites showing the sampling points and the N concentration deter- •
mined at each site on July 5, 1967. The dotted lines indicate the zone of influence bf each |piezometer, i
In order to determine the discharge of water from the barnyard, and ultimatelythe discharge of N, theHydralic conductivity of the medium has to be know. Fig. 5 shows
• I
the conductivity values determined for •the medium in the vicinity of each piezometer.i Based
upon these values, the region between the bedrock and water table was divided into three re- •
gions having different hydraulic conductivities. The•lowest region has a conductivit_ of |.35 ft/hr, the middle region••.10 ft/hr and the upper region .02 ft/hr. The increase _n con-ductivity with depth may have been the result of coarse textured materials being deposited i
at the bottom of the trough in the bedrock during the_process of glaciationo _ i |A convenient method, based upon Darcy's law, for determining the discharge of
water through a given area is by the construction of a quantitative flow nets. The m_thod •is demonstrated in Fig. 4 and 5. m
l Lateral flow lines were drawn to include all the water affected by the barnyard,(Fig. 4)_ Additional flow lines were drawn in such a way that orthogonal squares were form-
ed with the equipotential lines. Provided the potential drop between adjacent equipOtential
I lines is it be shown that the stream tube betweenone unit, can discharge per (the area two
adjacent flow lines_ per unit depth (thickness) of the medium is equal in magnitude to thehydraulic conductivity of the medium. Fig. 5 shows the stream tubes of Fig. 4 projected on
I the cross section through the barnyard. The discharge through the element of stream tubee,f,g,h, will be .02 ft.3/hr while the discharge through the element i,j,k,l, will be.35 ft3/hr. The total discharge of water will be the sum of the discharges through the indi-
l vidual elements of stream tube and was determined to 2.41 ft.3/hr on July 5, 1967.Similarly, using the concentrations in Fig. 3, the discharge of N through the
element e,f,g,h, was .02ft3/hr x 62.4 ib/ft 3 x 15.5 ppm x 10-6 = 1.93 x 10-5 ib N/hr and the
l discharge through element 2.71 10-4 ib N/hr. The total would be thei,j,k,l, was x discharge
sum discharges through the individual stream tubes and was determined to be 2.19 x 10-3 ib
N/hr for the conditions of July 5, 1967. Obviously the calculations would have been much
R simpler had the conductivity and N concentration been uniform throughout the cross-section.
The concentration of N in the water before it passed under the barnyard was
I 2 ppm. Of the 2.19 x 10-3 ib N/hr being discharged from the barnyard, 0.3 x 10-3 ib N/hrcould be attributed to N in the water before coming under the influence of the barnyard.
Thus the contribution of N to the groundwater made by the barnyard on July 5, 1967 was
l (2.19 - .30) (10-3 ) = 1.89 x 10-3 ib N/hr.
By performing similiar calculations at various times throughout the year the contribution of
l N to the groundwater for the year could be determined. The relationship between such var-iables as the discharge of water, the discharge of nitrogen, the nitrogen concentration in
the groundwater beneath the barnyard, precipitation and others could also be examined.
l Fig. 6 shows the distribution of contaminated water in the vicinity of thebarnyard. The importance of knowing the direction of groundwater movement in predicting
the spread of contaminants is amply demonstrated in this diagram. A well located 50 ft. up
i 'stream in the groundwater flow system from the barnyard would be unaffected by the barnyardwhereas one located as far as 400 ft. down stream would contain an unacceptable concentration
of N in the water. It should be mentioned that the nitrogen was almost entirely in the ni-
l trate (NO3) form. (Limits of i0 ppm and 5 ppm NO3 - N have been recommended for consump-tion by humans and livestock respectively.
i As mentioned previously, the topography of an area may not be a good indi-cation of the direction of groundwater flow. Fig. 7 is a topographic map of the study area.From this map the predicted direction of flow Would be from the barnyard towards the stream,approximately at right-angles to the actual direction of flowo
I Summary
l The movement of contaminants depends upon the chemical nature of the contaminantas well as the hydrologic and geologic conditions of the disposal site. Within the ground-
water flow system the movement is closely related to that of water. As expressed by Darcy's
E law, the direction and rate of groundwater flow depend upon the hydraulic potential gradient,and the hydraulic conductivity of the medium.
It should be emphasized that in many respects groundwater contamination is more
I serious than the contamination of surface water:
i) It is longer lasting because of the slow movement of groundwater.
I 2) It may not be detected until after a considerable part of an aquifer isaffected.
I 33
I3) Reclamation of an aquifer is difficult, if possible at all. m
From the diversity of substances and circumstances knOwn to have resulted in Icontamination problems, every material deposited at the earth's surface should be consid-ered as a_potential groundwater contaminant until proven Otherwise.
FIGURE LEGEND
|Fig. i A typical piezometer and water table observation well installation. :
Fig. 2 A map of the study area showing the sampling locations (04) and the lines of •equal hydraulic potential for the conditions of July 5, 1967. I m
Fig. 3 A cross section through sites No. 4, 5 6 and 14 showing the water table!ele - m' ._
vation and the nitrogen concentrations determined for the conditions of July 5, I1967.
Fig. 4 Flow net drawn to determine the discharge ofwater from the barnyardforitheconditiDns of July 5, 1967. :_
Fig. 5 Cross section through sites No. 4, 5, 6 and 14 _howing the distribution of the •
hydraulic conductivity values. The dotted lines divide the cross section into
three zones having different conductivitieso The lower zone was assigned a
conductivity of .35 ft/hr, the middle zone .i0 ftihr and the upper zone i02 •
ft/hr. The dashed lines indicate the Pr0Jection of the stream tubes of _ig. 4o I(e,f,g,h) and (i,j,k,l,) are one-foot thick elements of stream tube.
r
i- |
I I34 i I
Fig°
I _. '
I _ _..__4,, x 12'° clay ti le
ioI _ _surfacem . .; c.o.oIl
IWater
I _ +obOe / ( l iWater table
I ___ l " l observation we_iI
Piezometers
II
I !II J
I!
35
Fig. 2
I l I m i I i I
m - Fig. 3
I|
I . .. 37
Fig. 4 I
I
I'13 , I
I SCALE Isopleth interval0_. _0 mOO _._200 300 400
five ppm
i Feel
i Fig. 6 Distribution of average-total N concentrations
39
° Jl' II1.
--.... _ _I_ _x. II• p ',
I
: SGAL_" Contour interval I
-__-- --_ , 4_ one foot
Feel • .
• IFigure 7 Topographic map of the study area
40
I S.E. Salbach, P. Eng.,Program Engineer,
Water Quality Surveys Branch,
I Ontario Water Resources Commission.
SERVICES AVAILABLE FROM OWRC
I THE NEW POLICYON
I WATER QUALITY OBJECTIVES
." May I say, first of all, what a distinct pleasure it is for me to be here and to have this
Opportunity to address this gathering. As member of the Ontario Water Resources Commission,
/ _ _ I am a salesman of water, for its wise use and protection, and I never lose an opportunity,
,i_ therefore to speak on this subject, pollution control, and the role of the OWRC in the water_ management field in this province.i
This paper deals with two subjects:
1) services available from the OWRC
2) policy guidelines on water quality objective as recently adopted by the OWRC.
I May I make some preliminary remark concerning water management in Ontario, in-cluding a glimpse at the creation and functions of the OWRC, and then deal with the services
I available through the OWRC set to combat pollution and the major problems encountered in thfield of pollution control. I need not emphasize the fact that water forms the very basis
of !ife, without it everything perishes.
I As you water is renewable resource. Unlike minerals, for example, itknow, a
can be used over and over again. In its constant movement from earth and sea to the sky and
l back again, the world supply remains constant; there is as much water on the earth today asthere was in the time of Christ - and as there will be 2,000 years from now. Why, then, all
• the recent problems concerning water on this continent?
I The answer is the lack of proper water management ......... For this is of para-mount importance if we are_to ensure an equitable and maximum use for all purposes. The uses
of water are manifold the more important being domestic, municipal and industrial water
supplies, power and navigation, recreation and fishing, agriculture and the dilution of waste
I effluents. In a proper water management program each use of water is recognized and themaximum use of water for such purposes maintained.
I Why has water taken on new measures of importance today? Mainly because we arenow using it in greater quantities than ever before. Our per capita consumption is up - what
with our automatic washers, multiple bathrooms and lawn sprinklers which are today's amenities
i in the average home. Furthermore, there are more of us today. Society, too, is becoming moreand more industralized. Industry has a tremendous thirst for water° Consider, too, the re-markable way in which our way of life has changed since the last war. The work week has be-
come shorter. There is more leisure time for recreation, the summer cottage, boating and
I water sports. This, of course, is reflected in our booming tourist industry and we all canappreciate its importance to our economy. Taken together, this all adds up to increasing
need for water - clean, potable water - sufficient to meet the need of individual citizens,
I growing industry, expanding agriculture, and a recreation-minded public. Hence the impor-tance of water management!
m 41
I
• !Considering the situation in Ontario, with its myriad of lakes, rivers and streams
(the great lakes, alone, comprising some 20% of the world's fresh water supplies), we can only
reflect upon our fortunate position and the munificent manner in which divine providence has m
blessed this province. However, superabundance can create a myth in the minds of PeOPle -mm
the myth that such natural resources are inexhaustible and indestructible - with the _result
!that they may use them with careless disregard for the future, fresh water supplies, ino matter
how abundant, can become polluted, and it is imperative, therefore, that we exert eve]ry effortto conserve them from waste and despoilment.
Before proceeding further, however, i would like to give some of the hisltoryleading up to the formation of the 0WRC. Following the second world war, there was c!on-siderable activity in the water supply and sewage disposal field due to a blacklog of' m
work and the availability of funds which had accumulated during the war. Construction •
slackened off in the early 1950's, however and the situation was aggravated by the fact thatm
more water was needed in some areas and available supplies were becoming polluted - parti-
cularly in small communities dependent upon private wells, The need became apparent Zfor some mnew financialarrangement and stimulus for this work to proceed at an accelerated pace once
more. , . _ _
- !In 1955, the government of the day created the "Water Resources and Supp.ly.Committee" to investigate the situation. Hearings were held throughout the province and-theneed for increased water supplies and pollution control measures was studied. The findings mm
of this committee resulted in the passing of the Ontario Water Resources Commission Act •on March 28, 1956, and the formation of the OWRC.
At the 1957 session of the Ontario Legislature, the act of 1956 was replaced by •
Bill No. 164 entitled "The Ontario Water Resources Commission Act, 1957", the latter act
greatly widening the scope oflthe Commission's program and at ,the same time setting out
certain procedures. It transferred from the public Health Act a number of sections Per- m
taining to water and sewage works and it also transferred from the Department of Mines |the supervision over well drilling operations. Empahsis was placed upon the construction of
water and sewage projects for municipalities and new authority was given to control the
pollution of waterways with a view to conserving and developing the water resources of the mprovince. This legislation game into effect on April 3, 1957
At present time, the commission is composed of a chairman, a vice-chairman and •
four commissioners. It reports to the Ontario Legislature through the Minister of Energy andResources management, the Honourable J.R. Simonett. Former commissioners include the Honour-
able J.P. Robarts, Q.C., Premier of Ontario, the Honourable C.S. MacNaughton, Privincial mTreasurer, and the Honourable, A.A. Wishart, Q.C., Attorney_General. • |
under section 16 of the OWRC Act, the OWRC is responsible for all phases ofwater management in Ontario, including pollution control. Also under the act, the OWRC was m
given the authority to enter into agreements with municipalities for the financing, design,construction and operation of water supply and sewage treatment projects. I might add that
this particular authority was unique in the world at that time and has since proven of great •
benefit to many municipalities It meant, of course , that municipalities could now ayall |themselves of more favourable financing and expert supervision of construction and operation
of both water ann sewage projects. You may be interested-to know that, to date , close to
400 projects (229 sewage, 168 water), serving more than 200 municipalities, have beenl devel- m
oped on this basis, at a cost of $156,000,000. Of these projects 282 are already in operationIN
the remainder being in various _stages of development. m,m
" m
While this arrangement, based on OWRC-Municipal agreement, provided a good deal mm
of stimulus _to the_construction of needed facilities, by !964 most of the municipalities that
could use this type of financing had been covered. You will realize, of course, that most •
of the large municipalities, in such instances, preferred to undertake such projects on their |own, being able, as they were, to borrow money as cheaply as could the province.
i
Because Of the fact, however, that the cost of OWRC projects appeared as a debt m
m
against the municipalities involved in such aggreements there were still a large number of42
I municipalities which could not forward because of current financial situations, and thego
restrictions imposed, therefore, by the Ontario Municipal Board. For this reason the Author-•
ity of the OWRC was extended in 1964 to allow the construction of wholly provincial-owned •
I water to municipalities at cost. In effect, this meant the entrance of the OWRC into theUtility business, with a municpality signing a service contract with the OWRC with respect
to its water supply°
I In August of 1965, this Privincial Ownership concept was extended _o includesewage works as well - both on an area and an individual municipality basis- whereby
sewage might be accepted and treated, again With the Late being based on usage (Usually per
l 1,000 gals.). The first of these provincial - and which has just_beennew projects one
completed - is the Lake Huron water supply system. This is a 30-mile pipeline, bringing water
from Lake Huron to the London area, with a 67 MGD capacity and built at a cost of $20,000_000°
I There are many Other water or sewage projects either under construction or at various stagesof development.
l Some of the advantages of this new program will be immediately apparent. As Ihave already mentioned, such a project does not appear as a capital debt against the muni-
cipality.
I In the spring of 1967, yet another extension was made to this program wherebythe province will build, as a provincial undertaking_ the local watermains or sewers in small
municipalities° (up to 2500 population). Up until this time all such local works had to be
l undertaken by the municipality either on its own or as an OWRC-Municipal project°
In this new provincial program there has been provided a new stimulus to the
i construction of water supply and pollution control works throughout the province° The pro-gram is now well under way_ with over 150 applications having been received from munici-palities, and with a considerable number already under development° I might add that another
important advatnage associated with this type of project is that it overcomes the problem of
l compromises being made by municipalities either with respect to the degree of treatment orthe type of construction undertaken° As a consequence, the OWRC is now able to tighten up
• on municipal pollution control. As I have pointed out, a municipality now has three choices
I by which it may undertake to construct necessary works -- on its own;
- as a standard OWRC project based on OWRC-Municipal agreement;
i - as a new provincial projectNo account of the pollution control problem would be complete without a refer-
ence to industrial pollution. Because of the progress which has been made in the control of
I pollution from municipal sources, the 0WRC is now able to focus its attention, in a par-ticular way, upon pollution caused by industry. In this connection, the OWRC is adopting
a tougher attitude towards offending industries, realizing, as it does, that this problem
l must be remedied as well.A firm step forward was taken by the _commission in industrial waste control by
the sending of a directive to the pulp and paper industry in December 1964, this, in turn,
I being followed by a directive to other industries springin the of 1965.
I might point out that the OWRC will undertake an industrial waste treatment
l plant as a project, but the agreement for same must be made with municipality in which theindustry is located.
I The approach to industry is similar to that taken to municipalities. In thecase of the latter, where there is no treatment, or where plants are over-loaded or obsolete,
such municipalities must appear before the commission and a program for corrective measuresmust then be worked out. In the interim period, development within the municipality is
l curtailed. • No new subdivisions are approved no sanitary sewerand extensions permitted.
Similarly, with industries discharging pollutants to watercourses a like course of action isfollowed. Such industries are required to meet with the commission and correctiveprograms
I are then hammered out. In some cases where the commission is not satisfied with the pro-gress which is being made or the co-operation which is being received, injunctions and43
prosecutions follow° The terms of the OWRC Act apply with the same force to industries as •they do to municipalities, and in some instances, in fulfilling its responsibility for the
i
protection of the province's water resources the commission has no other alternative than to i
have recourse to the courts. In all fairness, it should be added, however, that industry •on the whole has been co-operating in a commendable manner and a marked improvement is now
taking place in the quality of the province's water courses, as a result.am
While industries and municipalities may be considered to be the greatest users iof Water, increasing demands are being made by agriculture as well. Shortly after the com-
mission was formed, new developments took place in the techniques of irrigation with ithe nresult that the practice of irrigation spread rapidly. With this, of course, the demands for •
water likewise increased - especially in the tobacco and market garden areas° As a resultm
the commission was frequently faced with depleted streams and complaints of interference in
water use. _ i
After a complete study had been made of the situation, the OWRC embarkedl on a
program of water-taking regulation, with appropriate changes being made in its legislation. •
A permit is now required for water-taking for most pruposes in excess of i0,000 gallo_s per |day. While, initially, the tobacco country was the first area to be regulated, most of the
province is now covered by this regulation.
Let us now for a moment look a little more closely at the commission's piollution U
control program. No one will dispute the fact that pollution control goes hand in hand with
any water management program. Over the past few years, a pollUtion control program has ibeen developed in Ontario which is sound, is gathering momentum, and is designed to clean up
what pollution still exists° The number of communities without sewers or treatment is grad-
ually diminishing. I have already made reference to the types of OWRC projects that are nnow available to municipalities in order to undertake a project and effect a remedy to its iwater supply or pollution control problem. Where such works are needed, sewer extensions
will not be approved (under OWRC Act the designs for all water supply and sewage treatment n
projects must be submitted to the OWRC for approval before the project is undertaken) Where i
pollution problems exist within a municipality because of the lack of adequate treatmenti
facilities, recommendations are made to the Department of Municipal Affairs against f_rther
subdivision development until a satisfactory program has been worked out. To decrease, nrather than permit the increase of existing pollution must be our objective° l
As I have already mentioned, the same policy applies to industry. If industry •does not co-operate, the OWRC can prosecute. i
Other areas of pollution control occupying the attention of the Ontario Govern-
merit at the present time include the Great Lakes. As a result of a reference from the •governments of Canada and the United States to the International Joint Commission, the
government of Ontario Water Resources Commission, is involved in a program of investigations
of pollution in the Great Lakes in co-operation with departments of the federal government. •
High priority is now to be given to the carrying out of these investigations as well as toa study of measures which will diminish the pollution of Great Lakes Waters. At the present
time, the OWRC is working on Lake Huron, the St. Clair River, Detroit River, Niagara River •and Lake Ontario. Special laboratories have been established to handle the samples being •
collected by the boats which the OWRC is operating. Specifically, the OWRC will concentrateI
upon an inventory being made of wastewater discharges flowing directly into the lakes, an
investigation of harbour pollution, and near-shore water quality investigations, including ndiffusion and assimilation.
There are many problems in practicing pollution control. The development of •economic treatment methods to control satisfactorily the discharge of undesirable was_es to Bthe environment sometimes are out-paced by the rapidly expanding industrialization and the
associated development of many exotic new compounds and wasteflowso There is the question
!
n of pesticides and herbicides about which relatively little is known in so far as their effectsin water, the biota, the build-up in fish. I mentioned these problems only to point out
theconcern which must be had over the increasing use of many new chemicals today before we
I know their long-term effect. A special section has been set-up in our laboratory to dealspecifically with new compounds.
i With the development of confined livestock production, liquid wastes are beingproduced in large amounts in relatively confined quarters in an increasing number of cases.
The same waste treatment problem faced by municipalities and industries must be met by thefarmer.
I A problem receiving increasing public attention is the nutrient (primarily phos-phates and nitrogens) input to our streams and lakes. These nutrients if present in excess-
n ve amounts, accelerate the aging processes of lakes by the production of excessive algaegrowths which pose major problems by interferring with water supply (taste and odours),
recreation, esthetic enjoyment, depletion of dissolved oxygen necessary for aquatic life and
i others. Elimination of nutrients by waste treatment within sewage treatment plants may bethe answer and research for an economical method is being carried out by the OWRC and many
other agencies all over the world. There have been constant cries to ban detergents which
supply phosphates to our waters. Phosphates have been singled out as likely to be the con-
I trolling element in the growth of algae and more research on the relation of phosphates tooverfertilization is carried out. As you probably know, a recent conversion to Biodegradable
Detergents has just taken place.
INEW POLICY GUIDELINES ON WATER QUALITY OBJECTIVES
I With the predicted large future population in Ontario, useincreased _and reuse
of our waters will take place. We must raise our standards for degrees of treatment and
qualities of municipal, industrial and agricultural effluents, and water quality in general.
n in late 1966, a committee on water quality objectives was formed within the
commission. The work of the committee covered an appraisal of the existing objectives. In
I he course of its work, the committee reviewed key aspects of the technology of environmentalwater quality analysis and forecast. These basic consideration were followed by a review ofthe water quality objectives employed by various state, provincial, national, and interna-
tional agencies. Study was made of the concept of the beneficial use of water and the need
I and review then made of the legal and jud-for quality criteria to control pollution a was
ical aspects of the problem.
n With the benefit of this background, the committee developed conclusions of itsinitial work and formulated a series of suggested guidelines for future policy as well as a
possible time table for completion of revisions to the objectives. The guidelines and the
I ubsequent procedure comprise the preliminary report of the committee on water quality objec-tives. The committee is continuing its work and will be presenting a second report within
the next few days.
I The Preliminary Report Includes:
The development of a statement on the basic objectives for water quality in
I ntario, the development of plans for water quality control in drainage basins where higherthan the minimum requirements are needed and an interim procedure for the case by case manage-
ment of pollution problems until specific plans for the major drainage basins or systems are
I evolved°The work of the committee led to the following conclusions upon which the policy
i guidelines have been founded:i. Understanding of the polluting effects of both treated and untreated municipaland industrial wastes on natural ground and surface waters has been incomplete.
2. One set of quality objectives intended for application across the province pro- •
vides too broad a base for the planning of pollution control measures in areas where
development is intensive or in drainage basins where low streamflows are common. •
3. Although minimum requirements are helpful in many cases, these should be mademore stringent in areas of intensive water use to make water available for all reason-
able uses. I
4. Objectives should be used as guides to develop alternative plans and designs for
the best use of water - this will lead to: _ i
(a) Care in the design and operation of waste treatment and other pollution con-
trol works for protection of public health and desired beneficial uses of
water, and i(b) judicious usage of waters for waste assimilation so that the orderly growth
of municipalities and industries in desirable locations will be possible.
• !5. Meaningful long term plans for pollution control in the drainage basins of theprovince will require the application of systematic methods of scientific andengine-
ering analysis, iI wish to now outline in detail the policy guidelines that have been adopted by
the commission.
POLICY GUIDELINES i
i. The provincial water resources should be utilized wisely in the best interests •of the people of Ontario.
This will require the restoration and maintenance of water quality for thegreatest possible use. i
Towards this end, water quality objectives take into consideration the use and nvalue of water resources for public, agricultural and industrial water supplies,
propagation of fish and wildlife, recreational purposes, aesthetic enjoyment i
and other legitimate uses. ii
2. There must be a constant effort to improve the quality of water, for it is re-
cognized that the improvement of the quality Of water makes it available for •more uses.
3. Minimum quality control objectives are set to apply to all waters of the pro- •vince - more stringent objectives can be set for any individual situation depen- idant upon use - and in the future, more stringent objectives may be set forspecific drainage basins or drainage areas.
4. Beneficial uses of water are the controlling factors in determining the water Bquality objectives in any drainage basin. Where the use of water for the assi-
milation of treated was'tes in a properly controlled fashion within a drainage •basinis recognized as a reasonable use, it should be compatible with other iuses of that water.
conservation values which contribute to the so- H5. Economic, health, aesthetic and
cial and economic welfare of an area are taken into account in determining thei
most appropriate use or uses of a water resource.
Therefore, in the establishment of water quality objectives for specific drain- R
age basins, the opinions of agencies or persons having an interest and/orresponsibility in the present or future utilization of the water in a particularbasin are solicited and evaluated. •
i
46 |
I 6. For each beneficial there certain whichuse, are water quality requirements
must be met to assure that the water will be suitable for the beneficial use.
The co-operative assistance of technically qualified persons who are special-
I ists with regard to various water uses are sought in determing the requirements.
7. Caution must be exercised in selecting numerical values for parameters to be
i included in any objectives for water quality - only those are included for whichsound information on applicable levels is available.
In the absence of appropriate numerical values, the objectives consist of
verbal descriptions in sufficient detail as to show clearly the quality of water
l intended.
8. Water quality objectives will be revised periodically as new information and
l conditions develop.Objectives will not be considered final or absolute as increases in scientific
knowledge of the effects of wastes on the environment will inevitably require
l alterations.9. All wastes, prior to discharge to any receiving watercourse will recieve the
best practicable treatment or control.
I Such treatment must be adequate to protect and upgrade water quality in theface of population and industrial growth urbanization and technological change.
l i0. Water quality objectives provide an engineering base for design of treatmentworks by municipalities and industries. Such objectives enable municipalities
and industries to develop realistic plans for new plants or expanded facilities
l without uncertainties about waste disposal requirements.ii. Effluent requirements based on the applicable water quality objectives for a
drainage basin will be established for each user by the commission, in order to
l maintain acceptable water quality for all beneficial uses within the drainagebasin.
Requirements may be revised when necessary to allow for increasing or new uses
l of the waters of a drainage basin.12. Any user who discharges wastewater that does not meet requirements established
by the commission, or otherwise impairs the quality of the water, is subject to
l provisions OWRC Act.the of the
The report following the statement on Policy Guidelines will cover the
l following aspects: -
1. A re-statement of the Policy Guidelines.
l 2. Definition of the basic water quality objectives applicable to all waters of the
province (values for the parameters chosen are expected to reflect criteria for
l the most restrictive uses).
3. Definition of meaning of stringent or more precise objectives and conditions
i under which these would apply and4. Definition of effluent requirements, that is, conditions under which septic
effluent constraints would apply. It should be noted that under the above
l arrangement, where the OWRC will set the constraints to apply in the case ofeach user, the concept of "stream classification" as it is popularly regardedhas little meaning. The key to the new objectives will be that the OWRC will
I be able to make major inroads into the problem of environmental water qualitycontrol by developing more specific treatment plant designs and industrial waste
controls tailored to the receiving water and its use.
Water quality criteria for the following major uses activities are being evalu- •ated by the committee at the moment -(we expect to include criteria for ground wateras well
I
as surface waters)
recreation and aesthetics •
public water suppliesfish, aquatic life and wildlife
agricultural uses Iindustrial water supplies
The most restrictive criteria will probably appear as the basic objectives about to be pub _
lished, l
A further step in the committee's work will be to develop actual limiting criteria for
a wider range of uses in the above categories. There are people who may feel concerned that
the commission is abandoning its clean waterpolicy. Certain industries may feel that theOWRC is granting concessions. - This is simply not true. If anything, it could be stated thatthe commission, by adopting this new policy has drawn attention to the need for improving
control over environmental water quality, and will be imposing specific, and in most cases, •more restrictive controls. In drainage basins where this appraoch is adopted both munici- |palities and industries will be required to adhere to specific effluent requirements. We
will reduce the "Judgment Factor" in granting sewage and industrial treatment works approval.
Rather than pretend that wastewater disposal is a use that should not exist, the commission •has recognized this as a necessary use. We cannot play like the ostrich - particularly when
the commission issues certificates of approval for plants with effluents, it is better to
know the effect of the effluent on the stream and take this into account in settling design •
limitations. This appraoch of effluent limits in plant operations may require, if necessary,court action for enforcement.
There are three possibilities in Water Quality Control. I
i. Ideally, maintain pre-civilization water quality conditions.
2. Maintain quality at a level required_by the most critical use of the water of
specific drainage basins or areas. Meaning that although its pristine purity I
maybe lost, deterioration below the beneficial use level cannot be tolerated,and
3. Establish more restrictive requirements than necessary to satisfy the beneficial •uses, to allow high level of quality and meet future growth needs. Obviouslywhere it is possible to incorporate a "Safety Factor" on streams or lakes where
little use has occurred would be very desirable. •
|On the 0ther hand, if the priority of beneficial use is high enough, then theobjective should be set correspondingly - EXAMPLE - calling for waters in Great Lakes Harbours
to meet the same criteria as waters outside the harbours, i.e. - swimming criteria? is_ sim- •ply not realistic. |
In regard to the three alternatives, we think that in most cases, we will operate at
• !the. second one. In the situation where a municipality or industry is loading a river nearthe limit and another user comes in above or below and causes the former to become illegal,so to speak, in ease.three we may or may not have a problem depending on the magnitude of
the load. In case two each_user would have to cut back. Ig
The new objectives will give the OWRC a sharper tool with which to resolve increasing
use conflicts. IWe Need To Know:
i. The Residual effects of wastes introduced to a lake or a river, often many miles away Iat points of subsequent use, This would lead to better sharing of the available re-source bythe users, and
2. The dollar benefits that will result from any pollution control plan or alternatives. I
!
I The bare bones of the administrative process comprise:involved would
i. A study of the water needs within a basin and population trends and,
l 2. Definition of water qualitY changes occurring and expected to occur undervarying waste load inputs.
I 3. Definition of limits to be placed on wastewater sources.
4. Determination of the costs involved and a clearer understanding of the benefits
I derived.
How Is This New Program To Be Put Into Effect?
I Until definite plans for water quality control throughout heavily used drainage
m
basins are developed, effluent requirements will be established for individual users.
l This arrangement will permit determination of the effluent requirements on thebasis of the effects waste discharges have on the local water envir0nment_ It will allowreasonable use of a stream or lake for waste disposal until an overall plan for pollution
I Control in the basin be developed, while also providing assurance that thedrainage can
approved use will be reasonably compatible with the eventual plant.
l What effects will this have on municipalities and industries? A more realisticapproach to waste treatment keyed to the use that is being made of the water. Treatment units
can now be specifically designed to meet the needs of the receiving stream. Under these new
l guidelines unreasonable demands concerning the degree of treatmentwill be eliminated. Apoint long made by industry - that demands for higher degrees of treatment than necessaryshould not be made. This new policy is not stream classification. It is a scientific
approach to the use of our waters based upon new trends and ideas. There will be no low-
R of water presently in use for the waters of Ontario.ering of the present objectives quality
No change is comtemplated in our present policy regarding industrial waste treatment. The
waste treatment program will continue and, in fact, will be accelerated. This is simply a
l more realistic approach to water use.
m 49
Professor T.H. Lane, lDepartment of Soil Science,
University of Guelph.
!MANURE MANAGEMENT AND UTILIZATION FOR CROPS
!Livestock and poultry production in Ontario are complimentary to crop production
andwill be in the future. Historically most animal manures have been spread on the soil forcrop utilization. However with increased intensification of poultry production manure hand- •
ling and disposal on some farms has become a much greater problem.
Large scale confinement swine and beef operations are rapidly approaching the •intensity of the poultry industry. |
Let's look at some agricultural enterprises producing a manurial waste compar _
able to the human excrement (not including garbage and other wastes) produced by a city of lI0,000 people: i
500,000 chicken broilers per year
50,000 laying hens per Year •
5,000 market hogs per year i1,000 beef cattle per year
500 dairy cattle per year I
Soil and Water Pollution
The nitrogen in manure can be a major contaminant Of surface and ground water Iwhen excessive amounts reach the water supplies. Waters high in nitrates are a hazard to
the health of animals and humans. Ii
Nitrate poisoning of livestock from consuming silage or green forage contain-
ing excess nitrates (from either manure of fertilizer) has been know for many years.
At recommended rates of application the nitrogen in manure does not present awater pollution hazard or a poison hazard for livestock.
The phosphorus and potassium in manure do not represent a problem in teinns of lcrop production or a water pollution hazard except by soil erosion. In most cases continuous
applications of manure result in, a build-up of phosphorus in the soil and lesser accumula_ •tions of potassium. These levels do not interfere with crop production.
Crop Production l
Fortunately in most of Southern Ontario corn is adapted and is ideal for a crop
utilization system of livestock wastes. The integration of soil, manure and crops (corn, U
forage, potatoes, etc.) must be a major part of any production system.
Land spreading must be the method for disposal of poultry and livestock manure - •its fertilizer value being a secondary but extremely important consideration. The soil |provides both biological and chemical treatment that is superior to any man - devised treat-ment system to-date. ..
!
!
|
I TABLE i,
NITROGEN, PHOSPHORUS AND POTASSIUM EXCRETED
I FOR DIFFERENT KINDS OF LIVESTOCK
Nitrogen (lb.) Phosphate (ibo) Potash (lb.)
I i000 broilers (0-4 lb.) 155 70 60- i0 weeks
I i00 hens (5 lb.) 125I00 55
- 365 days
l i0 hogs (30-200 lb.) 115 65 40-175 days
2 beef (400-1100 lb.) 140 65 175
I - 365 days
i dairy cow (1200 lb.) 140 65 175
l - 365 days
l TABLE 2o
FERTILIZER VALUE OF LIQUID MANURE PRODUCED
l BY DIFFERENT KINDS OF LIVESTOCKManurel Total Value 2 Valuefl000 gal.(gal.) ($) ($)
i000 broilers (0-4 lb.) i000 25.50 25.00- i0 weeks
I °i00 hens (5 lb.) 940 25.25 25.00- 365 days
l i0 hogs (30-200 lb.) 1510 20.00 13.00- 175 days
I 2 beef (400-1100 lb.) 3440 29,25 9.00- 365 days
i dairy cow (1200 lb.) 3440 29.25 9.00
- 365 days
| 1no dilution of the manure
2 Valuing nitrogen at i0€ lb., phosphate at i0€ and potash at 5¢ lb.
l The manure by-product should be utilized as the main fertilizer requirement for
crop production. Additional fertilizer nitrogen where it is not required may increase the
l pollution hazard.
Estimates are presented of the minimum acreage of land required in continuous
l corn for the utilization of nitrogen in livestock manures as well as the minimum acreagerequired for pollution control.
I 51
TABLE 3. _ •
UTILIZATIONOFMANURES IN AN •INTEGRATEDLAND - LIVESTOCKSYSTEM B
N-Excreted Minimum Corn Acreage
Size of Operation (lb.) Crop UtilizationI PollutionControl2 I
i00,000broilers 15,500 i00 50
_:i0 weeks I10,000 layinghens 12,500 i00 50- 365 days
|1,000 market hogs 11,500 100 50-_175 days
200 feeder beef 14,000 i00 50 B
- 365 daysi
i00 dairy cattle 14,000 i00 50 i- 365 days
I
minimum acres required in continuous corn for efficient use of manure (in terms of nitrogen), i
2manure application to point where corn yield is not liekly to be reduced or pollution is
not likely to be a problem (in terms of nitrogen). For pollution control on sandy soils i
which are more subject to leaching (mainly nitrogen) the continuous corn acreage should ap-proach the minimum for crop utilization.
Air Pollution i
Unfortunately for agriculture the one problem that still arises - at least with ipresent manure systems - is an odor problem. It presents a challenge to our modern methods •
of farm operation. Any animal waste utilization system may fail eventually if the odor pro-blems associated with storage and particularly spreading cannot be reduced. In the context
of an integrated cropping system the treatment and handling of manure must be directed pri- imarily toward the reduction of the odor problem.
Farms are growing in production capacity and farm odors are growing in pro- •
portion. These farm operations will be the normal agricultural production operation of the ifuture.
Agricultural scientists will develop simple techniques to economically incor- B
porate oxygen into these raw animal wastes, thereby reducing the odor to acceptable levels.I
The resulting treated waste will be used in crop Production with a minimum odor problem and
a maximum of fertility value, i
Storage Facilities
Where adequate land is available these animal wastes can be stored and used on i
i
the land;
i
Under Ontario conditions the storage requirements should be large enough for at •least a 6 month storage during the period when the land is frozen, muddy or snow-covered. •
Manure Pits I
For the most part a manure pit is storage only, with very little microbiological
breakdown. There is often an odor problem, especially when the waste is being moved or spread. •This system will save almost all of the excreted nutrien,£s-inc_uding Q_gan$€_ma_ter. B52
I Lagoons .....
Lagoons have frequently been in trouble in Ontario due to the low temperature
I of winte_ months, frequent over-loading, not enough water to dilute the waste and sledgebuild-up.
i The fact that with lagoons the potential supply of plant food to grow crops isnot used, make such a system a poor answer.
Other Systems
E Compos_ing, stockpiling and dehydration of animal wastes are receiving consider-
able research attention. However, cost and lack of market outlets seriously limit these
l as significant disposal methods.
Processing animal wastes for ultimate sale does not seem at the present to be
i a significant avenue of manure disposal.At least four points must be considered in selecting a system of manure disposal:
(I) amount of manure produced
l (2) its fertilizer content and value as a replacement for commerical ferti-lizer
(3) disposal cost of each system
I (4) availability of cropland on which to spread the manure.Summary
l There is no economical way at present to treat fresh undiluted manure for disposa 1io
directly to streams.
2. Where adequate land is available these animal wastes should be used on the land.
E 3. Soil application is the answer for the future whether the objective is utilization ofdisposal.
!!!!m 53
iDR. M.H. Miller, •Dept. of Soil Science,
University of Guelph. ii
FERTILIZER USE AND POLLUTION
!Fertilizer Use In Ontario
The use of fertilizer in Ontario has doubled Since 1960 with the greatest in- i
i
crease being in the use of nitrogen (Fig. i). Fertilizer use is essential to our crop pro-
duction program in Ontario. Although many of Our soils have an adequate supply of one of the i
major fertilizer nutrients i.e. nitrogen, phosphorus and potassium, very few have an adequate isupply of all three.
m
The amount of fertilizer required on a specific field can be determined only by ia soil test. The Department of Soil Science operates a soil testing service in co-operation mwith the Ontario Department of Agriculture and Food. Recommendations are made for the amount
of fertilizer required for each crop to obtain the greatest net profit per acre. Fertilizercosts represent a significant proportion of the cost of production for most field crops. How- lever for high value, high production cost crops such as tobacco and fruit and vegetables, thefertilizer costs are less significant. It is therefore on these crops that the highest rates
of fertilizer are used. i
Fertilizer Use and Pollutiona
Fertilizer use is being accused with increasing frequency of being a source of Ipollution of the envrionment - particularly in relation to water supplies and foods.
speaking to the 13th Annual Ontario Industrial Waste iA Boston research director
Conference in 1966 is quoted as saying "improper use of fertilizers by farmers has causedg
a nutrient problem in many North American lakes and streams." An article in the November i,1965 issue of Maclean's magazine entitled "Death of a Great Lake" relates the growth of i
algae in Lake Erie to the use of fertilizer in Ohio (Fig. 2). In the same article it is
stated that "In Rondeau Bay, for instance .......... weeds grew to the surface and, in the
words of a local marina owner made the bay look like a field of wheat. Fertilizer washing •off farmland had nourished the weeds to unprecidented growth".
In a recent paper presented at a symposium sponsored by the American Associationfor the Advancement of Science it was argued that the nitrogen in chemical fertilizers was •
"poisoning" the food supply. Reference was made by the news media to nitrogen fertilizersincreasing the nitrate content in vegetables, but no mention was made of the fact that these
data were from a study using above average rates. I
The charge implied in these and other statements is very clear. However, the
evidence presented is very circumstantial. These articles undoubtedly contain facts, but i
the writers have failed to relate, in the most elementary form, cause and effect. One could, II believe, show a similar relationship between the growth of algae in Lake Erie and the num-
ber of television sets sold in Ohio. No one would, however, conclude that the T.V. sets nwere responsible for the weed growth. Similarly, the increasing use of fertilizer does not •
necessarily mean increased eutrophication of our lakes and streams nor "poisoning" of ouri
food supplies.
It is essential that we have an understanding of all sources of pollution andthat the problems are accurately presented.
Is fertilizer use a pollution problem? To answer_this question realistically
it is necessary to have an understanding of the reactions fertilizers undergo when they iare applied to the soil.
I Use and Water PollutionFertilizer
Nitrogen and phosphorus are major components of fertilizer and are also the
l nutrients which cause the most concern in water pollution. These fertilizer nutrients mayenter our water supplies by two routes: (i) leaching through the soil to the ground water
Or (2) being carried either in solution or adsorbed to soil particles by surface runoff. .
l Phosphorus
l Phosphorus fertilizer when applied to the soil reacts very quickly with iron,aluminum of calcium to form compounds _which are only S!$_g_tly soluble in the soil solution.
The amount of water soluble ph0s_horus decreases to iiess than 10 per cent of that appliedwithin a few days of application o Thus there is very little vertical movement of phosphorus
I in the soilo This is demonstrated by the distribution of fertilizer phosphorus in a Burfordloam soil to which 700 lb. of P205 per acre were applied over a seven year period (Fig. 3).
There was little increase in phosphorus test below the 12 in. depth. At least a protion of
I the increase in the 6 to 12 in. depth can be attributed to mixing during plowing.The phosphate content of_tile drainage waters from fertilized and unfertilized
plots has been measured since 1961 by scientists at the Canada Dept. of Agriculture Soil
l Substation at Woodslee 2. The six,year for the unfertilized and fertilizedaverages plots
were 0.i01 and 0.109 lb. P/ac./year, an increase due to fertilization of_only 0.008 ib./ac./year.
l From this evidence we can conclude that FERTILIZER USE IS NOT CONTRIBUTING TO
POLLUTION THROUGH LEACHING OF PHOSPHORUS TO THE GROUND WATER.
!iMiller, M°H. Unpublished Data, Dept. of Soil Science, Univ. of Guelph.
I 2Aylesworth, J.W. Personal communication.
Because there is little vertical movement of phosphorus in soil, fertilization
I increases the phosphorus content of the surface soil. Therefore, soil carried by surfacerunoff from fertilized fields will be higher in phosphorus than that from unfertilized fields.
If fertilizer use is contributing to buildup of phosphorus in our water supplies, it will be
i in this manner. _Certainly there is considerable loss of :soil from cultivated land by surface
runoff. Many estimates have been made of soil losses by erosion. The problem is to deter-
l mine how much of this soil reaches our streams. The movement of soil from the top to thebottom of a slope,while undesirable from a crop production standpoint, will not contributeto pollution unless the sediment is carried directly into a stream, pond or lake. Several
l studies of the phosphate level in streams have been conducted. _Missingham (3) found thatthe phosphorus content of the Grand River increased by a factor of i0 when the river passed
from a predominantly agricultural watershed into more populated areas. Owen and Johnson(4) measured the phosphate level in several streams flowing into Lake Ontario. The yields
l of P from predominantly agricultural watersheds phosphorousvaried between 97 and 200 lb. of
per sq. mi. per year. Two predominantly urban watersheds (Highland Creek and German Mills
Creek) yielded 7,000 and 9,700 lb. P/sq. mi. per year. The annual yield from the
l Stouffville creek which drains a predominantly agricultural watershed but receives wastesfrom the village of Stouffville was intermediate. _ In the Highland Creek watershed, the yield
of phosphorus from urban land drainage was 5 to i0 times that from agricultural land drain-
I ge. The authors concluded that agricultural land drainage made a significant contributionto the phosphate content of streams. They stated , however, that the yield could be attributed
just as logically to streambank erosion.
I Studies in fact, shown that the sediment load carried Buffalohave, suspended by
Creek, N.Y° was reduced 40 per cent as a result of streambank erosion control measures on
only 20% of the streambank within a 145 square mile watershed (2). Obviously a significant
rk
and possibly major portion of the sediment comes from streambank erosion, i
Although surface runoff from_agricultural lands enrichedby fertilization can- e
not be disregarded as a source of phosphorus in our water it obviously is much less sign•- •ficant than urban runoff and municipal wastes. i
Nitrogen , i
The buildup of nitrogen in our Streams and lakes has also been attributed to
fertilizer use. Much of the fertilizer nitrogen is added in the ammonium form. The ammon- •
ium ion (NH4.) is adsorbed on thesoil particles and therefore moves slowly in the soil; The lammonium ion is however converted to nitrate (N03-) by microbial action. The nitrate ion isnot adsorbed to a significant extent and is thus free to move with the soil water.
NH4+ NO 2- NO3- I
microbial action
If a solution containing ammonium ispassed through a soil column, very little iammonium will appear in the effluent (Fig. 4)._. The nitrate in the effluent Will however
increase rapidly after a short time due to conversionof ammonium to nitrate. If the supply •
of ammonium is withdrawn the nitrate is quickly washed from the soil (i).
Thus, if nitrogen in excess of that which the crop can use fs applied to the •soil, nitrate nitrogen will be leached tothe groundwater. This has been demonstrated on lplots at the University of Guelph. Two hundred pounds of nitrogen as urea (which is quick-ly converted to the ammonium form) were applied to corn on a Guelph loam in the spring of __
1965 (5). There was no yield increase due to this application. • The nitrate nitrogen content iof the surface foot of soil was measured periodically on the fertilized and unfertilized
plots. There was a rapid buildup_of_:nitrate in the spring and early summer with a decrease
during the growing season probably_ue, to crop utilization (Fig. 5). In the early fall, •
however, the fertilized plot contained a high level of nitrate. This leveldecreased very Irapidly with the onset of fall rains. By December i, the level was the same as on the
unfertilized plot. The nitrate nitrogen content at the 18 to 24 inch depth in November,1965 was 8 0 _ lb. N/a €. The following April, the content was approximately i0 lb. per acre° iThe trial was repeated in 1966 with similar results. In December 1966, the groundwater
m
contained 66 ppm of nitrogen in the nitrate form. When we compare this level with the i0 ppm
considered to be the upper limit for human use we must conclude that at that particular time ithe groundwater beneath the plot was polluted. Such concentrations in a restricted volume
will soon_be diluted to a safe level. If, however, such conditions were applied to a large
proportion of our agricu!tural land, we would be faced with a very serious pollution pro- •blem. I
Thus if high levels of nitrate nitrogen are present in the soil in the fall and
spring pollution of groundwater can occur _. There are two factors that control the nitrate ilevel - namely the rate and time of nitrogen application_
I
The rates of nitrogen recommended for crop production in Ontario are designe d ito give the farmer the greatest profit per acre. These rates we believe will no_ Cause
unacceptable increases of nitrates in our water supplies. A few farmers, however, use higherrates thani_those recommended. These higher rates may cause buildup of nitrate in our ground- •
water. ..... IThe timin_ of the nitrogen application is also important. We have made the
point that high levels of nitrate in the Soil in the fall are undesirable. The practice of Ifall_applica_ion of nitrogen for spring planted crops has many advantages fo;r_both;the farmer_ i
and the "_ 'fert1_llzer industry. It has been claimed that nitrogen applied in the ammonium form
in la_e fall will not be converted to nitrate until spring due to the low sqlil temperature° •
lThere!_,isconsiderable evidence in Ontario however that over half of this nitrogen may be lost
over _nter. _hare is also evidence that conversion of ammonium to nitrate does take place| ' ;
56 i
!and thgt_ at least some of the nitrate is leached to the groundwater.
! ,Nitrogen fertilizers when used unwisely can therefore contribute to an unac-
ceptable buildup of nitrates in our water supplies. If, however, nitrogen fertilizers
l are applied at the time andrates recommended, there is little pollution hazard.
Fertilizers Use and Food Qualitx ....
| "The application of fertilizer to the soil will under most conditions increasethe nutrient concentration in. the _lant. Of the three major fertilizer n_trients - nitrogen,
phosphorus andpotassium - only nitrogen can accumulate in toxic quantities_ Plants can
i abs0rb nitrogen ineither the_nitrate (NO3r) or ammonium (NH4+) form ....However in mostOntario soils the ammoniumform is quickly converted to nitrate so that most of the nitrogenis absorbed in this form .....Thenitrate following absorption by the plant,is, converted to
I organic materials, primarily proteins .....Much of thisc0nversion_occurs in.the_root. If,however, the_nitrate supply.in_.the_soil.is_high,.the.rate of absorption will-exceed the
plants ability_to use.theonitrate.and.accumulation-occurs. Most roots and vegetative parts of
i well _ertilized plants will contain..somemitrate.nitrogen. The amount fluctuates,greatlydepending on climatic conditions as well as the nitrate content of the soil. Vegetables
such as spinach, kale and beets, are usually.higherlin nitrates than..other vegetables.
! •It.is.possible to..have.nit_ate.levels in crops that are toxic.to livestockor to infants. With infants thenitrate.ion (NO3) may be reduced, to,nitrite-..(NO 2) byorganisms in. the,stomach .... If the.nitrite_is..absorbed into the blood stream, it can rob
I the blood of oxygen causing methemoglobinemia (blue baby). After six months of age thenitrate is not converted to nitrite so the problem does not arise.
There is little data available on nitrate content of baby foods Sold in
I Ontario. Studies in Missouri have found samples of beets and spinach sold as baby foodsthat contained nitrate levels that could be cause for concern. These were a small per-
centage of those tested however.
l Certainly if excessive rates of nitrogen are applied to vegetable crops usedfor baby food, problems can arise. This is not likely to occur from fertilizer use due
l to the cost of nitrogen. It is more:likely to occur where animal manures are applied.Summary
l The loss of phosphate fertilizers from agricultural lands by leaching anderosion does not contribute significantly to the pollution of our water resources. The
literature states definitely that industrial wastes, effluents from sewage treatmentsewage
l systems and septic tanks are the major sources of phosphorus,Nitrogen fertilizers when used unwisely can contribute to an Unacceptable
buildup of nitrates in our water supplies. If, however, nitrogen fertilizers are applied
l at th_ rates and times recommended, cropproduction ban be maintained at optimum levels
without creating _ pollution probiem. '
l Excessive applications of nitrogen may lead to unacceptable nitrate levelsin baby foods or livestock feed. This is more likely to occur from applications of animalmanure than from fertilizers.
I References
io Erh, K.T_, D.E. Elrick, R.L. Thomas and C.T. Corke, Dynamics of nitrification in soils
I miscible displacement technique. Soil Sci. Soc. Amer. Proc. 31: 585-591,using a
1967.
l 57
2. McDowell, L.L.•and E.H. Grissinger. Pollutant Sources and Routing in Watershed Programs. iProceedings of the 21st Annual Meeting of the Soil Conservation Society of
America, Alberquerque, New Mexico, 1966.
3. Missingham, G.A. Occurrence of phospahtes in surface waters and some related p_oblems, i
Journal American Water Works Association, Feb. 1967, pp. 183-211o
4. Owen, G.E. and M.C. Johnson. Significance of some factors affecting yields of phosphorus Ifrom several Lake Ontario watersheds. Pub. No. 15, Great Lakes Research Division,
TheUniversity of Michigan, 1966.
5. Progress Report, 1966. Dept. of Soil Science, University of Guelph. I
II
IIIlIIII
II
l
| 2o
I10
Ii 1960 1961 1962 19G3 19_.,4 1985 1988
I Figure io Fertilizer use in Ontario 1960-1966.
_ iI
Im
IJ I
' I("b
- !ALGAE "" " " " _'-"-"._-.Y_ -_
,_,,_ .... , _000 / .= .|500 _m
A primitive life form, al_,ae look like g,reen :_slime. Nourished by pollution, they have LakeErie in a death lock, some say, they have set •up a cancerous life cycle that can't be broken. 0 II
, _
' ",ooo n-......_ J _g II.. ...... :a'7,'__ c
FERTILIZERS /a._.=.---.S/ _;1_ F q _= I_oo _They held make the Erie drainage area a land _ _ _oV'-- °_ Iat plenty. But When they drain into _he lake :_they fertilize weeds tha t clo_ several bays,one of which looks "like a field at wheat." 0
IFigure 2. Reprinted from Nov, 1, 1965 issue of Maclean's magazine with permission
of Maclean-Hunter Publishing Co. Ltd. •
|•I
I• |
00 I
0
,,i'IIlYl{D i '. ,;I_I'II.II'. .. . _ ..,;.I)
DEPTH 12
18
SOIL
(INCHES) 2..:.
! I I I
0 I00. 200 500 400
PHOSPHORUS SOIL TEST VALUEw
Figure 3. l)isti:JbutJ.on cf fcl-t:ilizcl: pho:phoru,'; ill a'l;u_,-fo_'d lo_un to v:hJch 700 lb. P2Os/ac.we_:e applied ove_. a scv_., ycar period.
200 - .I
! \ IN FLU E N T• i'103-N / .\C:..t,,._,J6EDto "
150 ' . _ / . .' \DISTILLEDNIT,_OGFN ,:_
INI00
, I..U_::NT
(p p rn).
" ,NIl4 N . ". . 'i
50 /I
o .,.,,,,•,.-<_,.,,">-_.,,,0 .5 I0 1,5 20
:J"I_;l[- (da7s)
Figure 4. Nitrate (NO3) and ammonium (NHA) in effluent when solution containing ,.NH4-nitrogen was passed through soil core.
240 -
R. R. Parker, P. Eng _, •Consulting Engineer, •
Acton, Ontario
,|.LANDDISPOSALOF WASTESFROMMILK-AND CHEESE PLANTS.
• !PROBLEMS ENCOUNTERED. SOME REFERENCETO OTHER INDUSTRIAL WASTES.
A little consideration will indicate to anyone that land disposal is the obvious
method of_disposing of unwanted liquid wastes, and there is a good deal of human nature and Bbehaviour to justify the practice. To begin with, more persons live away from water than •beside it and the method was convenient. Then too, it was not in 0ne's best interests to
I
dispose of unwanted water in the tepee or the back of the cave. As civilization developed
and the use of water increased the way to the disposal area was through the kitchen door. ,,I
Further development of organized disposal on the land can be expla_ne d byi. Lack of other facilities B
2. Lack of knowledge of other disposal techniques |3. Economics.
In following the terms of reference in this discussion; there will be little
mention of other methods of waste disposal This is not to be considered as a rejection of •
other methods, preferable as they may be in some instances, but they will have been dealt •
with in adequate fashion elsewhere in this course, and the repetZtion would not be justified.
Briefly, there are three principal systems of land disposal of industrial efflu- lent.
i. Ridge-and-furrow irrigation
2. Spray irrigation
3. Injection pumping mand we wili deal with them in that order. The order of mention is primarily chronological,
rather in order of: importance. I
Ridge-and-furrow irrigation is the oldest method of disposal, because of its
mechanical simplicity, and there are many references to it in the literature. Accounts of
the use of this method for sanitary waste disposal antedate any record of industrial waste ltreatment and the first mention of its use in industry was in the late 1920's.
l
The method consists of flooding furrowed or ploughed land with the liquid waste, []and subsequent permeation of the soil, without run-off. Furrow sizes differ, A 19th century mBritish text (i) describes the method, A report that in my opinion is the most comprehensiveavailable was prepared by F.H. Schraufnagel in 1962 (4). A summary of the history of the •
method, taken from this report, includes the following points of interest: |Ridge and furrow irrigation was first utilized at about the middle of the 16th
century by the town of Bunzlav in Germany. A similar practice was initiated at Ashburton in []England in the early years of the 18th century (5).
In England the Royal Sewage Commission was appointed in 1857 and in a report of •the Commission's conclusion the following appears (6):
The right way to dispose of town sewage is to apply it cantinuously to land, and •it is only by such application that the pollution of rivers can be avoided. |
In 1930 the literature carried reports of a _ajor irrigation operation by the
Mission Dairy of Phoenix, Arizona (2). The discharge was reported to be 60,000 g.p.d, of a. I
chlorinated septic effluent applied to a 10-acre field. Waste flowed in eight furrows whichm
64 I
m .were filled in about twelve hours and ploughed_under every day. Another statement described
the soil as fairly tight and uniform. The labour involved in this treatment system seems
l excessive by today's standard and it is difficult to understand why such intensive cultiva-tion was required.
i In 1950 a creamery in Minnesota installed a ridge-and-furrow system that, accord-ing to reports some twelve years after its installation, continued to function satisfactorily.This was a field of 2.8 acres, underlaid with one line Of tile at about 3 ft. depth. Analy-
tical figures reported showed a feed of 210 ppm B°O.D. and a tile effluent of 3 ppmo The
l plant was handling 40,000 ibs of milk per day.
In Wisconsin the first system was at the Mindoro Co-operative Creamery in 1954.
l This system covered about 3 acres and apparently was designed with the_previously describedoperation as a model. Milk intake was 50,000 ibs per day, and the wastes averaged 30,000
g.p.d., including cooling water. Influent B.O.D. was reported as 300 ppm. Average daily
l loading of 23300 gal. and 58 ib B.O.D. per acre were standard practice. The system obviouslywas not overloaded and it was estimated that the overall results showed a B.O.D. removal of
over 95%.
l Wisconsin has pioneered in the use of ridge-and-furrow treatment and in a paperby Schraufnagel in 1961 (3) a summary of operational figures is given. Application rates
ranged from less than 2500 to over 30000 g.p.d, per acre and the range of B.O.D. loadings
l was from i0 to i000 ibs per acre per day. In addition to the above, somewhat higher B.O.Dloadings were encountered at a few plants when excess whey was included in the effluent.
A short review of the main types of milk processing and their characteristics
I is inserted at this point, to provide backgroundknowledge for those whosecontact with the
dairy industry has been chiefly that of a consumer:B.O.D.
l Whole milk i00,000 p.p.m.
Skim milk 70,000
l Butter milk 60,000
Whey 30,000
l These values may seem surprisingly high, and they also will emphasize the seriousness of the
problem of adding milk plant wastes in uncontrolled fashion to the influent of a bio-oxidation
I reatment plant. These high B.O.D. values also point to the feasiblility of land disposal,as in general it can be said that the critical value in land_ disposal is volume, rather thanB.O.D. It is true that other constituents of the waste - total solids, basicity, dissolved
I solids, can be of major importance but normally in assessing the problem of sewage treat-ment the primary parameters are hydrawlic loading and biochemical loading. One should notjump to the conclusion that B.O.D. levels can be disregarded in the design of land disposal
systems, but fortunately the shock effect is not a factor and temporary overloads do not
I the operation as they do in the conventional sewage treatment plants.upset may
Ridge-and-furrow irrigation is the least expensive method of controlled waste
l disposal - the word controlled refers to all systems other than the indiscriminate releaseof effluent to public water courses, - and this low cost naturally enhances its attractive-ness.
I It is perhaps wise at this point to digress briefly from the purely operationalaspects and to consider the mental attitude of the industrial plant operator, as in most
instances sewage and its treatment are considered as having nuisance value only. If all in-
l dustrial effluent contained salvageable material our total pollution problem would be onlya fraction of our present condition and the burden of enforcement agencies would be light-
ened. The resistance of the plant owner or operator to departmental guidance, control or
i
penalty - to cover the full range of governmental action- is frequently not due to lack •of sympathy or agreement but because compliance with departmental rulings may have a
serious effect on profits - the ultimate reason for being in business_. Understandably,a plant owner is concerned and frequently resentful when he is informed that a major •
expenditure is necessary in order that he comply with pollution abatement regulations.
Remember that in most cases departmental criticism is directed at established procedures,
and the owner is understandably reluctant to incur increased expense to deal with time- ihallowed operations. H
It can be said with fair assurance that the technical answers to pollution
control problems are available to all of us and in this sweeping statement we include Bpractically every type of manufacturing waste. You will note that the word "answers"
was modified by the word "technical". Any operation involving chemical change that is
capable of technical control carries with it the technical procedure for pollution control •
and abatement. This sounds like an answer to all our problems but that is far from the Bcase. The principal factor in waste treatment today is economic, and the situation is
frequently a complicated one. Tile possibility of technical answers may be negated by i
the impossibility of economic operations, ii
As regulatory officials you undoubtedly will be expected from time to time
to consider the economics of this problem. This is not a plea to forego pollution Rcorrection, but merely to point out that it is much easier towrite standards of purity
for water, air and soil, than to achieve them. In some instances, the damage caused by
pollution may justify any action, including cessation Of industrial operation, but this •
drastic step should only be taken after careful consideration by technologists and ieconomists.
i
Inasmuch as this discussion is concerned to a major degree with the dairy •industry, this phase of the problem is of extreme importance. Where the operation is
i
not large and the percentage of profit small even small extra expenditures may verge onthe impossible. To those members of this audience who come from counties where cheese •
and butter making are not confined to a few large scale operations, this is not a new |idea. Cheese factories with only three or four workers can not consider major expend_itures for equipment which promise no added income, but guarantee only increased opera- iting expense. i
To return to specific treatment Of dairy industry wastes, ridge-and-furrowirrigation has definite advantages and disadvantages. B
On the positive side: i
i. - It is the cheapest to install.
2. - It has a high resistance to neglect. •3. - Shock loading is not a factor. i4. - Variations in loading, unless excessive, are not critical.
5. - It is reasonably satisfactory for all-season use. •
The disadvantages:
i. - Land contours are important.
2. - Land re-working is a major operation, i3. - Odour may be a factor.
4. - Soil type is important.i
Considering the advantages as listed, the low cost is due to absence of high-head pumps, Iand consequent high pressure lines, spray equipment and its maintenance.
Provided that the area is adequate for the volume of effluent and that the i
system has been laid out properly, _the system can function with _amodicum of atten-D
tion. True, it is preferable to keep the system in good shape but it is not essen-
tial. Failure to control the vegetative cover produces more inconvenience than imalfunction. i
66
!
i Within the limits of the furrow size and contour, shock loading is not a
factor. Over-filling of furrows is, of course, to be avoided, as run-off with consequent
i more-or-less widespread contamination of nearby water courses will occur. Furrow erosionalso is an undesirable result of excessive loading. But shockloading, as one knows it
inconventional treatment plant operation, does not exist.
I Ridge-and-furrow operation in winter in Ontario is possible. Three precautionsare advisable:
i.- The system, if not a year round operation, should be in use before the per-
I iod of heavy frosts. There is danger of run-off in the wastes when appliedto areas of deep frost penetration.
2.- The temperature of the effluent is preferably in the over 60°F range.
i 3.- Sludges are not acceptable, but in the dairy industry this is not usuallya factor.
In examining the disadvantages:i.- The land contours must be such that ploughing is not difficult. In addi-
l tion to problems encountered in ploughing it is not easy to maintain afield when slope s are steep.2.- Cultivation at least once and preferably three times a year is recommended.
l Removal of vegetative growth and breakdown of furrow system is necessaryand occasional deep tillage is advisable.3.- Odour in warm weather can be a factor. Where the percolation rate is slow,
there is a chance of odour development but this is not a factor in winter
I operation.4.- Percolation rate is important in planning an area of adequate size. Long
term testing is the only dependable criterion at present.
l Spray irrigation has been utilized quite widely in the disposal of dairy indus-try wastes although the more dramatic applications have been in other industries. Possibly
l the best known system was that developed at Seabrook, N.J. This has been described in bothtechnical and non-technical press (7). The first mention was in 1950 and similar accounts
appeared in other semi-technical publications. This installation covered an area of 150
acres and handled an annual volume of one billion gallons of waste water.
l Reduced to its basic elements, spray irrigation is the application of effluent
by means of a pump, pipe system and atomizing nozzles to a tract of land, preferably covered
l with vegetation.
As with ridge-and-furrow operation, there are both advantages and disadvantages.
l For large volume operation it is my opinion that spray irrigation is to be preferred.The principal advantages are:
io- Land contours are not important.
l 2.- B.O.Do shock loading is not important, but volume, within limits, is.3.- It is not affected by rainfall, within reason.
4.- Very little attention required.
l 5.- Utilization of forage crops is possible.6.- Odour is not serious.
7.- Annual re-working, after establishment of the cover crop, is not necessary.
l 8.- Attractive appearance of the disposal area.The principal disadvantages are:
i.- Mechanical complication.
l 2.- Unsatisfactory winter operation.3.- Cover crop cutting.
4_- Satisfactory soil type is essential.
!I 67
Treating these points in some detail, slopes that are too severe for contour •ploughing can be used. With proper cover and application rate, run-off is not a factor. It
is also possible to Spray in wooded areas, provided that excessive moisture does not damage
young tree growth. B.O.D. loadings of 200 lbs per acre per day are considered as a prac- Itical working limit (8) but in my experience this figure has been tripled for a period 6f m
one month without undue damage to a cover crop. Following the 200 ib value, and applying it
to whey, one should provide 17 acres of land for the disposal of the whey from a i00,000 lb. •
daily milk intake. This, of course, is based on no util$zation of whey _ a highly waste- |ful operation. In this abnormal operation whey loading overshadows the wash-water load.
Rain, within normal levels of precipitation, is not a problem. With a dailyapplication of 0.3 to 0.5 inches per day, and bearing in mind that a daily application of0.75 inches can be tolerated for several days, an occasional increase of 0.25 inches due to
rain is not a serious matter and can be disregarded. With a well designed system the opera- ltional labour is not a problem. An occasional change of sprayed area and periodic examination iof sprinkler heads for clogging is all that is required.
The sprayed fields can be pastured - if there is sufficient land to permit the Iwithdrawal of pasture areas from irrigation service as required. It'is questionable whether
the pasture value in most cases is sufficient!y high to justify the extra cost of installation
and operation, l
Thanks to the high degree of aeration, the odour problem is minimized. True,
odour sometimes is apparent but there is very real lessening of the problem as compared with •still lagoon or ridge-and-furrow operation.
Examining the drawbacks to this method, the prime one is the use of high pressure i
pumps and lines. A pressure of 30 psi at the spray head is about the minimum that will provide |satisfactory atomization, and with extended systems, T.D.H. levels of 75 to i00 psi are en-
countered. Frequently this necessitates the use of 3500 r_p.m, pumps and, of course, heavier
lines, l
In my experience, winter spraying in ontario is not a very satisfactory operation.
Accumulation of ice on the fields makes travel to spray heads slow and dangerous, is apt to •have a very serious effect on the cover crop, and the resultant run-off in the spring oftencreates a contamination problem.
Regular cutting of the cover crop is recommended because the condition of the I
cover is improved, fields are out of service for very short periods, and from the standpoin tof public appearance it is very well worth while.
• !Again, a satisfactory soil type is of importance. Obviously , percolation through
a tight clay soil is not as rapid as through lighter soils, even though the heavy cover cropimproves the liquid transfer. Certainly it can be said that there is more leeway in soil •characteristics for spray as compared with ridge-and-furrow irrigation use.
The combination of spray irrigation and ridge-and-furrow is, in my opinion, to mRbe preferred. The ridge-and-furrow advantages overcome to some extent the PrOblems of winter |freezing and crop damage, while ease of application and 0dour control indicate the preference
for spray methods in the warmer weather.
The third system of disposal, to my knowledge, has not been used for dairy wastes. I
Deep well or injection pumping is usually confined to the treatment of heavily polluted wastes
where, because of the degree of contamination or because of unfavourable local conditions,
other methods of disposal are either not possible or not feasible. Basically, the method con- |sists of pumping the waste into underground rock formations. This can be a very satisfactorymethod of disposal but there are many restrictions to its usefulness.
!The first and very obvious one is a complete avoidance of discharge into fresh
water aquifers. The upper portions of a disposal well must be sealed against undesirable
l leakage and, of course, the local geology must be such that a permeable stratum is availableunderground. The cost of drilling is fairly high, and thesurface equipment is expensive ashigh pressure pumping units usually are required. It is essential that all suspended material
l be removed from the effluent before injection, as otherwise the rock formation may be irre-mediably plugged and the well rendered useless.
l The method has been used to some extent in the petroleum industry where largevolumes of saline wastes present a disposal problem. Chemical process wastes that are expen-
sive or difficult to treat may be disposed of by this method and it also has found at least
l one application in the paper industry in the United States. It is unlikely that many of thosehere today will encounter any examples of deep well disposal but this brief discussion of the
process is justified, on the premise that some mention of it should be included in any study
of land disposal methods.
l So far we have discussed only the three methods of land disposal and in so doing
wemay have created theimpression that complete disposal is the only approach to dairy in-
l dustry effluent problems. Another phase of the problem may have occured to you, and that isthe apparent waste of usable and salvageable material. This approach to the disposal of what
might be called primary residues is of the utmost importance.
l from recent the Farm Economics Branch of the OntarioQuoting a publication by
Department of Agriculture (9) the annual production of whey in Ontario is 893,000,000 ibs.,
based on cheddar cheese production_only. Of this quantity 420,000,000 ibs. is fed to hogs
l or otherwise disposed of. Translating this into whey solids, 20,000,000 ibs. of whey solidsworth approximately 5¢ per lb. is used for feed or other purposes - sometimes uneconomic.
If we indulge at this point in a little mathematical exercise and assume that one-half of
l this material is dumped, then 200,000,000 ibs of whey with a B.O.D. equivalent of 7,000,000ibs is discharged as potential pQllution. Using a population equivalent of 0.16 ibs B.O.D.
per capita per day we face the annual equivalent of a city Of 120,000 poPulation. It is
reported that 127 cheese factories were in operation in Ontario in 1967. Therefore, the
l equivalent soil and water pollution for each operating unit is the equivalent of a villageof i000 persons. When one considers that many plants have very satisfactory treatment
facilities the magnitude of the problem, and its economic implications, are emphasized. It
l may well be that treatment of Eesidual whey on a break-even or loss level may be the solutionto this serious problem. °
l Of course, the disposal of whey, buttermilk, or other unused residues does notpresent a complete solution to the problem. Container rinsings and other wash water,'andother contaminated effluent water still combine to produce an appreciablevolume of high-
strength effluent. Where good housekeeping is the rule, one can expect a volume of approx-
l imately equal volumes of milk in and water out. As a numerical example, a cheese factoryprocessing 40,000 ibs of milk per day will produce about 4000 gal. of effluent with a B.O.D.
rating of i000 - 2000 p.p.m. This spread of 100% is not unrealistic as differences in pro-
l cess and facilities can account for this variation. Recalling the B.O.D. value for wholemilk of i00,000 p.p.m., the variation may seem surprisingly low.
l In addition to milk processing many other industries contribute to our pol-lution problem. Canneries are in the front rank here, but fortunately for the pollution
problem a major number of them operate during the period of non-freezing weather. Usuallylocated in the smaller towns or semi-rural areas, a shortage of land has not been a problem
l and in consequence of this fortuitous combination, spray irrigation has been adopted in anunlber of instances.
l The adoption of this method of disposal has been widespread in the Unites Statesand the use of spray irrigation is increasing. An adaptation of the method which has been
operated successfully covers the inclusion of comminuted vegetable pulp with the sprayed
l effluent (i0). Normally this material is screened from the effluent stream and handledseparately. Trials demonstrated that the comminuted fibre could be mixed with the liquid
69
!
portion of the waste and then sprayed. Obviously the ground particles must be small to •avoid clogging the spray nozzles, and also the fine material does not accumulate on the dis g iposal area as coarser material would. The vegetable material acts as a mulch, just as shortgrass cuttings on a lawn, and it is reasonable to anticipate an improvement of the sprayed mR
area with use. i
Two other notably successful applications of land disposal have been in the
pulp and paper industry and in tanning. AS the earlier pulp mills were built, of necessity i
they were situated on rivers, and thus had a very convenient and low-cost disposal system.
A gradual change in public thinking has effected some modification Of this pioneer rtreatment
process. Due to the rugged terrain in which many pulp mills are located, some variety in •the method of application is encountered. Disposal in a bush covered area is common, _be- icause of a shortage of cleared land. In one instance at least a fleet of tank trucks
equipped with pumps and spray nozzles was utilized. A grid work of roads was bulldozed in
a wooded area and the effluent discharged directly from the trucks. The capital cost of i
such a system is high and under normal conditions the cost of Operation would be well nighg
prohibitive but in this instance the rough country, the climate, and the extended pipe-
lines that would have been required upset the normal economics of disposal. In other pulp •mill systems, more conventional distribution systems were used. m
Several tanneries in North America have adopted land disposal where the avail- mability of land has made this possible. In other instances, tanneries are located in larger •
centres and it is possible to treat the industrial effluent in the municipal plant despiteu
the relatively high B.O.D. and large volume.i
One aspect of land disposal merits some attention at this point, and it is H
particularly applicab_le to paper mill and tannery disposal practice. In addition to organicconstituents these effluents contain appreciable quantities of alkali metal salts. The •
resultant reaction with the clay and silt fractions of the soil - ion exchange reaction to ibe specific - frequently modify the permeability of the soil, that all important factor in
land disposal. Numerical data have been drived by some workers (Ii) and a Sodium Absorp-
tion Rate has been developed. This is a relationship between the sodium-potassium and •
calcium-magnesium ion concentrations in the effluent. In some instances the changes in theg
irrigated soil have necessitated treatment with gypsum at levels up to one ton per acre
to reverse or control the zeolitic change in the soil. B
High Salt - specifically sodium chloride - content also can present a problem.
Salt is not digested, is not precipitated and is not adsorbed. It merely continues through •the soil strata and may eventually find its way into fresh-water aquifers. Within limits ithis will not detract from the value of the water buG excessive salt of course can be a
problem. The literature exhibits considerable variation as to what constitutes permissiblecontent of sodium chloride, influenced to a large degree by the use for which the water is •
intended. It is safe to say that levels below 250 p.p.m_ are of no importance in potablem
water supply, and double that amount has been encountered in many instances. Irrigation
of crops and stock waterings provide considerably more leeway. R
One other aspect of land disposal has been mentioned only in passing and that
is odour. To a considerable extent this can be controlled, although with some expense, iThe use of masking agents, aeration of lagooned effluent, addition of nitrates and some Battention to local weather conditions can go far in alleviating this condition.
In conclusion, soil disposal of industrial wastes is a useful method, gener- i
ally low in cost - both capital and operational - flexible and not susceptible to shock -
loading, but not foolproof. After twenty years of experience with its use, I recommendthat it is well worth consideration, i
i
i70
i
!BIBLIOGRAPHY
l (i) Crimp, W.S. - Sewage Disposal Works, 2nd Edition. Charles Griffin
& Co. Ltd., London, 1894.
i (2) Minotto, J. - Chlorine for Elimination of Nuisance from CreameryWaste - Abst. Sewage Works Jour.2, 393 (1930)
i Municipal. Sanit. I, 406 (1930).(3) Schraufnagel, F.H. - Ridge & Furrow Irrigation for Industrial Waste
Disposal - J.W.P.C.F. Nov. 1962, 1117-1132.
! .(4) Schraufnagel, F.H. - Waste Disposal by Ridge and Furrow Irrigation,
Wisconsin Committee on Water Pollution Report No. W P 108.
l Engineering Experiment Station Research Report No. 20.
(5) Metcalf, L. and Eddy, H.P. - American Sewage Practice Vol. iii, Disposal
l of Sewage. 3 rd. Ed. McGraw Hill 1935.(6) Crimp_ W. Santo - Sewage Disposal Works 2 nd. Ed., Charles Griffin
& Co. Limited (1894).
i (7) Newsweek Nov. 6, 1950 - "Bottomless forest".
l (8) Lawton, G.W. - Spray Irrigation of Dairy Wastes - Sewage & IndustrialWastes 31, 8, 923 (Aug. 1959).
(9) MacDonald, A.D. and Redelmeier, W.R. - Economics of Alternative MethodsI
, of Whey Disposal at Southern Ontario Cheese Factories -gFarm Economics Co-operative and Statistics Branch, Ont.
Dept. of Agriculture, September 1967.
! (i0) Canham, R.Ao - Comminuted Solids Inclusion with Spray Irrigated CanningWaste. Sew. & Ind. Wastes 30, 8, 1028.
I (Aug. 1958)(ii) Blosser, R.O. -Irrigation and Land Disposal of Pulp Mill Effluent.
l Proc. llth Ont. Industrial Waste Conf. 1964.
R 71
!
• iDr. D.E. Elrick,
Dept. of Soil Science9
University of Guelph. ii
PESTICIDE MOVEMENT IN SOIL
|The persistence of some pesticides inthe soil and the possible incorporation
of these compounds into some part of man's food cycle is one of the unforeseen problems of •pesticide usage. There have been some problems with the earlier inorganic pesitcides, such |as lead arsenate, but more recently some of the organic pesticides (in particular, the organo-
chlorine insecticides such as DDT, aldrin, dieldrin, etc.) have been accused of polluting ithe soil as well as other aspects of the environment. H
It is difficult to formulate broad statements about pesticide behaviour (and
movement in particular) in soils° This is because of the large number and variety of chem- iical compounds that are used as pesticides coupled with the variety of soil types ranging mfrom sands through clays to muck soils. Considering all the other variables (temperature,
rainfall, etc.) this means that potentially millions of different responses may be observed. •As a consequence, the accurate prediction Of the fate of a specific pesticide in a given soil |is extremely difficult; however, enough research has been carried out so that certain gener-alizations can be drawn.
Chemical Properties of Pesticides i
It is possible to group pesticides into Categories using a number of criteria i
but the following classification (Kirkham, 1963) offers one of the better groupingsrelative to water movement in soils.
Chemicals with a reasonably high water solubility, that are nonionic (alkyl Ialcohol, formaldehyde) or are organic acid salts where the toxicant portion
is anionic. The latter would include the sodium or amine salts of 2,4-D,
2,4,5-T, chlorobenzoic trichloroacetic, 2,2-dichloropropionic, and other Borganic acids. i
2. Soluble organic salts where the toxicant portion is an organic cation, suchas, quaternary ammonium germicides and pyridylium herbicides (Paraquat andDiquat).
3. Fat soluble and/or highly water insoluble non-ionic chemicals such as i2-chloro-6-(trichloromethyl) pyridine (N-Serve), DDT, organochlorine insec-
ticides, urea and triazine herbicides, and fungicides such as pentachloron- i
itrobenzene and captan. H
Chemicals with properties intermediate between groups also occur but can usually
be assigned to one of the groups, iS
Group (i) is not sorbed strongly by any of the soil constituents. Their move-
ment through soil would follow the same rules as movement of, say, nitrate or chloride, mGroup (2) could presumably be treated somewhat in the same manner as one treats movement
of cations (such as Ca and K) except that organic cations are usually much more stronglysorbed than inorganic cations. Group (3) offers a more complex problem. For chemicals with
relatively low water solubility and high fat solubility one can calculate distribution be- itween the chemical in water and that in the soil organic matter.
" ' i
72
!
!Tran______sport
l pesticides soils can take place in association with any ofThe movement of in
the three phases - solid, liquid and gaseous. Undissolved pesticidal chemicals and compounds
adsorbed to soil surfaces can be physically eroded (or washed) as solids down slopes; pest-
l icides in solution can run-off as surface water or be leached through the soil to ground-water supplies; and volatile pesticides can move through the soil pore spaces in the gaseousphase and be lost to the soil system at the soil surface.
I Soil Erosion
At Present there is the least reliable information (and consequently the great-
l est speculation) on the effects of soil erosion andpesticide pollution of surface water
supplies. The insoluble pesticides that would not leach can be transported with the soil
sediment and may eventually reach streams, rivers or lakes. Although classified as insol-
l uble in water, there is some water solubility (often in parts per billion) and the magni-tude of very low concentration in water supplies is difficult to evaluate.
l Soil erosion from agricultural land normally occurs under the following condi-tions: (i) from fallow or sparsely covered land, (2) from steep slopes Under intensive cul-
tivation, (3) during March and April when a thin layer of unfrozen soil receives an intense
rainfall, and (4) during storms with high intensities (Webber, 1964). Surface runoffs are
E greatest in the spring, and at this time the eroded material is dominated sediments thatby
are mineral in nature as well as easily dispersed organic matter containing nitrogenous and
phosphorus compounds. While tons of soil may be shifted by water erosion, it is difficult
i to estimate the small percentage that goes directly to a water supply.
Leaching Losses
i The movement of water in saturated or unsaturated soils takes place when thereare differences in the potential of the soil water between different phases in the soil
system. For example, water in soils which are completely filled with water will move down-
l ward after a rainfall because of the force of gravity; on the other hand, water may move inany direction from a dry to a wet region within the soils. Soils can be grouped with regard
to their ability to transmit water (Elrick, 1967) and thus can be used as one index in deter-
l mining the downward movement of pesticides.Within a soil, two basic mechanisms are responsible for the movement of chemical
substances: (i) diffusive movement because of variations in concentration between differ-
l ent places in a soil; and (2) convective (mass flow) of the soil solution. Coupled withthese mechanisms tending to bring about movement of chemical substances, reactions such asadsorption, precipitation, and chemical and biological breakdown influence the movement in
l a variety of ways. It is important to know the relationship between the concentration ofthe chemical in solution and that in the reacted phase.
l Perhaps the most important chemical property of a pesticide affecting movementis its solubility. In general, the greater the solubility, the greater the downward move-ment within a soil. For example, research has shown that the greater the rainfall, the more
I rapidly that the water soluble herbicide monuron leaches downward. On the other hand, therather insoluble organochlorine insecticides seldom are found more than several inches below
theplow layer.
! One of the most important properties of soils is their ability to break down
or decompose organic compounds. Primarily this is brought about by microbial activity
(bacteria, fungi, etc.) with chemical decomposition playing a much less important role.
I The layer of microbial activity is pretty well restricted to the soil surface (about a footthick). Once pesticides are leached below this layer there is little liklihood of any further
degradation of these compounds.
Volatilization I
All compounds are v0_latile to some degree. With the more volatile pesticides, •there can be considerable movement of the pesticide in the gaseous phase from the soil system |to the lower atmosphere. Fortunately, reactions of many pesticides with soil colloids andsoil organic matter reduces the volatility of the pesticide.
Formulation can also influence volatility. For'example, granular formulationsof herbicides will.have volatility characteristicsdifferent from non-granula r formulations.
Also with 2,4-D, the esters are more volatile than the salts, l
Both aldrin and heptachlor are relatively volatile and, as a result, disappear
quite rapidly from soil (Harris, 1967) Unfortunately, soil micro-organisms convert small •
amounts of aldrin to dieldrin and heptachlor to heptachlor epoxide. Both dieldrin and hep- |tachlor epoxide are highly toxic insecticides. In contrast to aldrin and heptachlor, both
metabolites are highly persistent in soil, dieldrin more so than heptachlor epoxide. DDT is am
itself highly persistent. It is not volatile, and is broken down only very slowly to much •
less toxic metabolites, DDE and DDD. The persistence and metabolism of all these insecticidesg
is influenced by soil type, moisture, temperature, method of cultivation, and amount of cropcover over the soil surface. The behaviour of these chemicals insoil is illustrated in •
Table i. It would appear that residues of DDT and dieldrin will persist in the soil for
many years.
Table i. Persistence and Metabolism of Aldrin, Heptachlor and DDT in Soils. l
i
Volatilization of Metabolites Produced as a Result l
Insecticide Parent Material of Soil Micro-organism Activity
aldrin Approximately 90% in first Dieldrin (approximately 10%) l
2 years
heptachlor Approximately 90-95% in Heptachlor epoxide (approximately ifirst 2 _ears (5-10%)
DDT Nil (highly persistent) DDE, DDD l
!DDT, aldrin and, to a lesser extent , heptachlor have been used extensively for
control of agricultural insects in Ontario. To what extent are our agricultural soils con-
taminated with these materials? Recently Harris et al. surveyed 36 farms in Western Ontario •for residues of organochlorine insecticides in soils (Table 2). While such a limited study
is by no means statistically significant, the summary of the data obtained does serve as
rough indication of the extent to which our agricultural soils are contaminated with organ- m
ochlorine insecticide residues. It is apparent from the data shown in Table 2 that our agri- |cultural soils are contaminated with residues of the organochlorine insecticides. The degree
of contamination in most cases is not great, with total organochlorine insecticide residues
!being approximately 2 ppm or less (based on a 3" acre, 1 ppm of insecticide is approximately
1 ib per acre). In tobacco and vegetable soils, where insecticides are used extensively,
the degree of contamination was greater. In orchard soils, high levels of DDT and related
materials were present. •
• !_ 74 l
I Table 2. Organochlorine Insecticide Residues in Ontario
Farm Soils in Relation to Crops Grown.
!DDT Cyclodiene Insecticides Total
I and and Org anochlorineRelated Materials Related Materials Residue
(ppm) (ppm) ; (ppm)
ISugar beet 0.4 - 0.4
I Forage and pasture 0.5 0.3 0_8Corn i.2 0.2 i.4
Cereal 1.4 0.4 1.8
Greenhouse vegetable 1.5 0.8 2.3
I Tobacco 3.2 0.6 3.8Vegetable 9.5 i.6 ii. 1Orchard 61.8 - 61.8
!Although residues of the organochlorine insecticides can be found in Ontario
I soils, this does not automatically mean that there is a problem. It is necessary to deter-mine if the present use of these soils can lead to problems at some further stage.
SUMMARY
I The behaviour of pesticides in soil depends upon a number of complicating fac-
tors, such as the chemical form of the pesticide, the soil type, the soil water content,
I temperature, etc. The organochlorine insecticides have been extremely useful but they havealso been the ones most likely to cause residue problems. However, when problems have aris-
en, they can usually be attributed to misuse of misunderstanding.
I Presticides are here to stay. But the ones wehave must be used properly and
as the better pesticides (i.e. selective, non-persistent, etc.) are developed the problems
presently encountered with some pesticides should diminish.
I References
I i. Elrick, E.E. 1967. Soil Water Movement: theory and applications. Proc.First Canadian Conference on Micrometeorology, Part 2, 477-497.
2. Harris, C.R. 1967. Pesticides and our environment. Proc. Ontario Poilu-
I tion Control ,Conference 185 _ 95 _
3. Harris, C.R., W.W. Sans and J.R. Miles. 1966. Exploratory studies on
I occurrence of organochlorine insecticide residues in agriculturalsoils in Southwestern Ontario. J. Agr. Food, Chem. 14: 398-403.
I 4. Kirkham, Don. 1963. Some physical processes causing movement of ions andother matter through soils. Talk presented in connection with the
15th Annual Phytopharmacy Symposium, Ghent, Belgium.
I 1964. Soil properties and erosion control. J. Soil5. Webber, L.R. physical
and Water Conserv. 19: 28-30.
!I 75
Richard Frank iProvincial Pesticide Residue Testing LaboratoryOntario Department of Agricuiture and Food
PESTICIDE PROBLEMS I
• Introduction I
The National Committee of Pesticide Use (Canada) andthe FederalCommittee on Pest Control (U.S.A.) have been concerned with•the control of npests without the hazards to the environment and its inhibitants. Thesecommittees recognize that chemical methods will continue to be needed forsome time to come and so the long-term effects of such chemicals and their •residuesare being evaluated. The effects of pesticides may be directly Ion the target organism to be controlled or indirectly on other inhabitantsof the environment. In the application of a pesticide to a target organism, •the pesticide may become a contaminated of air, water, soil, plant, wild- •life and man. The termpesticide covers all compounds that are used byman u
to control pests whether they be_members of the animal or plant kingdoms.u
Insecticides and Miticides I
These compounds are used to control insects and mites respectively. •They fall into several chemical groups,• the most important of which arelisted below.
I. Chlorinated hydrocarbons - (a) the DDT group which includes meth _ ioxychlor, lindane, etc., and (b) the cyclodienes which include aldrin,dieldrin, heptachlor, endosulfan, toxaphene, chlordane etc_
II. Organophosphorus compounds - malathion, parathion, coumaphos, mronnel, •phorate, diazinon, etc.
n
III. Carbamates •- carbaryl, Zectran, etc. n
nicotine sulfate, etc •IV. Natural insecticides - pyrethrum, rotenone,
|•o I. Chlorinated Hydrocarbons. The Chlorinated hydrocarbons are thegroup that have precipitated so much investigation into chemical residuesin the environment While most of this group are of low mammaiiam toxicity,•they persist for a great number of years in both the environment and livingtissues.
m
A. DDT group. DDT is the best known and most effective of the synthe- Itic insecticides, however it is extremely persistent when applied to plantor other surfaces but is of extremely low hazard under most circumstances.The mechanism of action is little understood although it is generally agreed I •that its primary effect is upon the nervous system. There are five princi.i •
u
ple routes by which DDT is metabolised in varlous organisms, The firstthree routes involve the oxidation of DDT to DDA, Kelthane or dichloroben- izophenone. The fourth route involves dehYdrochlorination to DDE and thelast route involves reductive chlorination to DDD.
In vertebrates, it has been known for almost 20 years that DDA is amajor metabolite in faeces and urine. The pathway to DDA in rats has re-cently been reported in which DDT is first converted to DDD. In man, DDEis the principle storage form of ingested DDT and DDE does not appear to i
i
, 76 i
m be on the breakdown pathway to DDA. DDD is widely found in water, soi!,plant and animal tissues where DDT has been used but not DDD. Kelthane
l and dichlorobenzophenone appear to be the breakdown products of DDT infruit fly and cockroach. In the analysis of samples for DDT, it is usualto include most of the above metabolites in the total DDT group. Other
i chlorinated hydrocarbons are methoxychlor and lindane, both of which arerapidly metabolised in living tissues and rarely appear as persistentresidues.
l B Cyclodienes. This group includes aldrin, dieldrin, endrin, hepta-chlor, heptachlor epoxide, chlordane, endosulfan, toxaphene etc. The cyclo-dienes vary a great deal in mammalian toxicity but in general are more tox-
l ic than the DDT group. Endrin is highly toxic while a-chlordane is oflittle hazard. These compounds are neurotoxicants. The persistence of eachvaries greatly; dieldrin and heptachlor epoxide persist almost as long asDDT while aldrin, heptachlor and endosulfan have relatively short, termed
i residues.
Aldrin and heptachlor are volatile and rapidly volatilize into the at-
i mosphere. Some workers claim as much as 90% escapes into the atmosphere.Both occur in soil but in both soil and animal tissue they are convertedreadily to their epoxides, dieldrin and heptachlor epoxide, both of which
l are toxic.II. Organo Phosphorus Insecticides. Originally, these compounds were
developed (in Germany and England) as nerve gases for chemical warfare but
J were never used as such but were recognized as potent insecticides. TEPPwas the insecticide developed and marketed (Germany) and was soon followedby parathion (1944 - Germany). In general,_these compounds inhibit the
l enzyme, cholinesterase, in the nerve ending hence blocking the breakdownof acetyl-choline, the chemical which carries the electrical signals fromthe nerve ending to the muscle. It is widely accepted that organophosphates
i kill animals by inhibiting cholinesterase with consequent disruption ofnervous activity causing the accumulation of acetylcholine in'the nerveendings. Most organophosphates are extremely toxic to humans, e.g. parathion,phorate, demeton, TEPP etc., while a few are less toxic than DDT, e.g. ma-
I lathion. _ Many of the organophosphorus insecticides are converted to moretoxic compounds in the tissues before being detoxified.
l Few of these compounds persist for more than one season and do not pre-sent the problems of the long term residue as do the chlorinated hydrocar-bons. A small group of organophosphorus compounds do persist for up to aseason and their uses are restricted to avoid toxic residues in plant
l products. For example, dimethoate, applied lemons,to concentrates in the
peel with disastrous effects if fed to livestock.
l The greatest hazard of the organophosphorus compounds is at the timeof use and up to one week after use. They pose a real hazard as a contam-inant of food, as in the accidental contamination of iflour with parathion
i i(Mexico). Parathion has been deliberately used in suicide and homicide.III. Carbamate Insecticides. The toxic action of carbamates resembles
that of the organophosphorus compounds. Carbaryl has relatevely low mammal
I toxicity and Zectran toxicity, system ap-is of medium In the animal both
pear to be broken down and excreted in urine or faeces and do not tend topersist in the tissues or animal products. _!
I 77
Nematocides, Rodenticides and Piscicides i
These compounds are used to control nematodes, rodents and fish res-pectively, Each presents its own hazards and the user should be aware of ithe dangers to himseif and the lives of people and animals around him whenhe uses these compounds.
Fungicides _ i
The great majority of fungicides in use today are thiocarbamates and ias such are broken down both in living tissue and the soil so that to the •best of current knowledge, no problems of residue exist. Fungicide_ re,
i
sidues remaining on livestock feed are usually metabolised in the animal
and do not turn up in animal products. I
Herbicides
/' iThe use of herbicides has so increased that in many areas, it exceedsthe use of all other types of agricultural chemicals. Herbicidal activityhas been found in a wide variety of chemical compounds including chloro-phenoxy_acids, pheny!ureas, triazines, carbamates and others. Except when Bapplied in excessive amounts, herbic!des leave insignificant residues from
i
one season to the next. Few herbicides occur as residues in planttissuesand even fewer have been found to appear in animal products or in animal •tissues. Most are metabolized by living tissues. Picloram is one herbi- mcide that does persist in the soil and can find its way into water suppliesIt has however, very low mammalian toxicity but extremely high phytotoxi- icity. i
Registration of Pesticides mEach pesticide, before being registered by the Plant Products Division B
of the Canada Department of Agriculture, must meet a whole array ofrequi-rements. Unless its efficacy can be demonstrated, it is of little value ito agriculture. Knowledge on its direct and indirect effects on agricul- mture and food production are of interest to both Departments of Agricultureand Public Health and Welfare. Only after extensive testing is a licence i
procured. Specific label directions accompany each chemical pesticide and ieach formulation.
Mass deaths of wildlife, occasionai deaths amongst humans and domesticanimals have been associated with mishandling or misuse of pesticides,Nevertheless, the low background level in our environment is largely theresult of the Proper use of pesticides. Residues remaining from one year •to the next may be moved by water, wind etc. to contaminate the environment |at large. Strong attempts are nowbeing made to halt further build-up anddissipate existing residue levels. The Pesticide Act administered by the i
Ontario Department of Health is an attempt to prevent misuse and mishandl- •ing and keep a watch on the volume of dangerous chemicals being used in the
g
Province.
Air Contamination I
Minute traces of pesticide have been reported in the air over London, mEngland and oyer some California cities. Aldrin, heptachlor, many phos- Bphates, and some carbamates are volatile and can find their way into theatmosphere. Contaminated air may settle in other parts of the environmentafter being carried considerable distances. 2,4-D has been knOwn to vola- itilize and to drift from the site of application to other locales both far i
78 I
I and near for many years now. The recent case of endrin drift from _obaccoto melons over a distance of five miles caused an international crisis be-
l tween Mexico and the Uo S. A. when Mexican-grown contaminated melons ar-rived in Texas° Monitoring air is difficult to carry out and the data onceobtained is difficult to interpret.
l Water Contamination
Pesticides may be carried into or settle on water and, depending on
I their solubility or suspendability, they become minor contaminantsmay or
major pollutants of such water. Most chlorinated hydrocarbons are prac-tically/insoluble in water, e.g, aldrin, dieldrin, endrin, endosulfan, hep-
I tachlor, DDT, and methoxychlor. Only lindane of the commonly used chlori-nated hydrocarbons is soluble in water (i0 ppm). Of the organic phosphorus
compounds, most are miscible or readilysoluble.
l The Ontario Water Resources have enacted legislation controlling theuse of pesticides in or on water courses, streams and lakes, in an endea_your to reduce contamination of water supplies and safeguard wild life.
i Once in water, a pesticide can be taken up by water plants, and passedthrough many trophic levels to fish, birds, mammals and even man.
I Pesticides may enter water supplies by either direct intentional appli-cation, or inadvertent drift into water from adjacent spraying operation,or perhaps more commonly, by washing from pesticide-treated areas within
i the watershed. Fish are highly susceptible to many pesticides. Endrinand toxaphene are toxic to certain fish at less than 1 ppb while other chlo-rinated hydrocarbons are toxic at only a few ppbo Carbaryl and azinphos(solubility i0 and 33 ppm respectively) are toxic at similar low ranges,
l however these two are not important pollutants as they are relatively rap-idly hydrolysed.
I In a survey on a river system in Alabama where toxaphene, DDT and lin-dane were extensively used, it was found that toxaphene reached a maximumlevel of 0.4 ppb, lindane 0.75 ppb, and DDT could not be detected. Thiswas explained by the tremendous diluting and retention of these pesticides
l by soil. An foot of soil weighs about 4 million and holds a-acre pounds
bout 30,000 gallons of water, into this is applied a few pounds of insec-ticideo This amount of even the most toxic pesticide would be significant-
l ly below the level that would be hazardous on an acute or subacute basis.A survey of the rivers in the U. S. A., west of and including the Miss-
l issippi-Missouri was carried out by ii monitoring stations. The findingsfrom these stations revealed no herbicides were present in river water atany time during the sampling dates or at any Of the eleven stations. In-secticides were found at levels varying from 5 to i00 p p trillion. Lin-
I dane was the most frequently found insecticide being present in about 30%of the samples while aldrin was the least frequently found with 2% of thesamples° The level of pesticides in drinking water is usually extremely
I low (less than 1 ppb) and hence, when considering that human beings havea daily intake of 2 litres, the ingested pesticide would amount to only2 x 10-6 go
l In a study on the level of pesticide residue in streams adjacent toa commercial orchard, it was found that no significant contamination of anadjacent creek occurred. No residue was detected in the run-off water from
i the orchard that entered the stream. The level of DDT and dieldrin in thetrout was no different from the state-wide average.
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Residues: Fish, Wildlife and Esturines i
Oysters were collected from the esturines in South Carolina, Georgia, iFlorida, Mississippi, Louisiana and Texas and analysed for pesticide re- Dsidues. In general, chlorinated pesticides were either not detected orwere found to be relatively low in samples collected from the Atlantic andGulf of Mexico Coastal areas. In localized areas, the levels of chlorina- ited pesticides indicate thatcontamination of shell-fish growing waterscould be a potential problem that must be kept under surveillance.
i
In 1966, the Tennessee Valley Authority supplied 888 tons of 20% 2,4-D Hgranular herbicide to 8,000 acres of Eurasian watermilfoil growth in sevenreservoirs at rates of 40 to i00 lb. 2,4-D acid equivalent/A. Analysis mshowed little uptake by fish but some by mussels. All mud samples contain- •ed 2,4-D and plant samples had up to 1 ppb. The conclusions of the exercise
i
were that high application rates of 2,4-D for watermilfoil control did not
produce adverse effects on aquatic fauna or water quality, giSoil and Pesticide
Pesticide may settle on soil and may remain in the surface and later I
i
be moved by wind and rain or be leached through the soil. A pesticide mayby dissipated from soil in one of several ways. It may be (i) broken down i
by microorganisms, (2) leached out in the drainage water, (3) washed away •by surface runoff, or (4) vaporized into the atmosphere. The rate at whichthese processes occur determines the persistence of a chemical in a soil.It is now known that many of the chlorinated hydrocarbons persist for sev- •eral years and are only slowly lost from the soil.
The levels of pesticides in most soils in Ontario, however, are still iquite low and not giving rise to undue concern. Orchard and vegetable soils iare a special case, as the continued use over the past several years ofchlorinated hydrocarbons has given rise to relatively high insecticide re-sidues. Such soils, if used to produce livestock feed, can result in con- isiderable residues in feed and in turn in animal products. It is known thatroot crops, in particular, take up residues from the soil. Forages, to amuch lesser degree, translocate residues from the soil into the foliage and •these can also appear in the milk.
Crops and Pesticide Residues
When a crop is sprayed with an insecticide, the chemical undergoes one •or more of the following processes. It may be absorbed into the plant,moved around the plant, and broken down by the plant. The extent to which ithese occur determinesthe residue on the crop. Residues may be localizedon the foliage where they were applied or they may be distributed _through-out the plant. In the case of some root crops, some pesticides removed from ithe soil may be concentrated in the outer layer of the rootwhile thetop nmay be relatively free. Compounds like DDT and DDE are ubiquitious andoccur in trace amounts on many feeds and ultimately find their way into the i
milk, but usually at very low levels that are of little consequence. H
Crops that have been sprayed for insects and are suitable for sale forhuman consumption may be quite unsatisfactory for livestock feed. When iused for human consumption, a pesticide residue, say on a vegetable is con-centrated 10 to 20 times in the fatty tissues of the human body. Even aftersuch multiplication, the residue may still be relatively low. Feeding the •same vegetable to livestock, the residue is first concentrated 10 to 20 ntimes in the animal's body and then further concentrated i0 to 20 times bythe human body when the animal is eaten. This can magnify an original levelby i00 to 400 times. This multiplication or concentration occurs at each i
8O i
!tropic level in the food chain and explains how high residue can be foundin the fatty tissues of wildlife. Food and/Drug Regulations have a "no
I residue" tolerance for all chlorinated hydrocarbons in milk and for mostin meat. In order to produce this type of milk, a producer must be ab-solutely sure that the agricultural chemicals he is using_are registered
l for use on those crops destined for animal feed. There is enough inadver-tent contamination of the environment to give a trace in animal produce,and by adding to it by accident or design, a trace amount is soon raised
I to a detectable level.Livestock and Pesticide Residues
l Insects on Livestock_ may be controlled with a number of insecticides(Publication 91). Once the animal is treated, the chemical may be absorbedinto the body, moved around the body and broken down by the body. The rate
l of dissipation determines whether the chemical is suitable for use on live_stock, and on what type of livestock it can be safely used. Compounds likeronnel, pyrethrum, and carbaryl (Sevin) break down rapidly and leave non-detectable residues. These can be used on dairy cattle without giving a
I residue in the milk. Compounds like methoxychlor,toxaphene, lindane and
others cannot be used on dairy cattle because they turn up in the milk.However, they can be used on beef cattle, but only if used in the manner
I prescribed, i.e. methoxychlor, carbaryl (Sevin), and ciodrin cannot be usedcloser than 7 days before slaughter; while lindane, ruelene etc. cannotbe used for 30 days before slaughter. Each chemical is different and the
l specific directions found on the label must be checked before use.Residues in Animal Products
l Residues most commonly get into dairy products and meat in the follow-ing ways:
(I) Chlorinated hydrocarbons like DDT, dieldrin, lindane, chlordane,
l heptachlor epoxide, endrin and toxaphene appear in milk and tissue largelybecause of residues on feed. Such contamination can be brought about ina number of ways, (a) from spraying crops intended for livestock with the
I wrong insecticide, (b) from contamination of feed by spray drift, (c) fromfeeding by-products, e.g. potatoes, corn stover, etc. that contain resi-dues, and (d) from bedding containing a chemical residue.
I (2) Organo-phosphorus insecticides are largely inactivated in the ru-men and residues in the feed generally do not appear in the milk. Only "trace amounts appear in milk and then usually as a result of direct use on
l dairy cattle.(3) Carbamate insecticides are found in trace amounts for only a few
hours after feeding. Low level residues On the feed dolnot generally app-
l ear in milk.
(4) Fungicides and herbicides are mostly broken down in the rumen
I and do not appear in the milk. Dalapon is the Qnly one to be found toany extent.
I From July l, 1963 to June 30, 1966, 12,836 samples of milk and dairyproducts were analysed by the Food and Drug Administration, U. S. A. fromdomestic and imported lotso A majority of samples contained pesticide re-sidues. The residues of DDT, DDE, DDD, dieldrin, heptachlor epoxide, BHC,
l and methoxychlor accounted for 99.3% of thelindane, aldrin, heptachlorresidues. About 95% of the values were below .51 ppm on a fat basis and71.5% of the values were below .ii ppm on a fat basis. The average level
| 81
iof DDT plus analygues was .134 ppm, slightly more than i/!0 of the legal •tolerance of 1.25 ppm. The average levels for dieldrin and heptachlor were.042 to .036, or i/i0 the current administrative guides. In conclusion, •it is obvious that the total residue content of milk fat should not be per- mmitted to increase since this is the source of 13.6% of the total dietaryintake of chlorinated organic pesticides. Even though no major nationwide i
problem is obvious, there have been several instances of considerable con- icern to specific localities during this period. i
Man and Pesticide Residues HiSurveys in human fat have been conducted in the U. S. A., Canada,
Germany, France, Hungary, England, India, Czechoslovakia and Israel, The •total DDT,DDE group varies greatly from country to country. The levels in gU.S. citizens were relatively high (12 ppm) during the early 1960's whileEuropean levels were relatively low (3 to 4 ppm). In the late 1960's, itappeared that levels in other parts of the world were overtaking the levels iof U. S citizens. A report from India gives levels of up to 30 ppm andIsrael up to 18 ppm while most recent U. S. A. figures show little changefrom the i0 to 12 ppm level. European nations report levels of about halfthose of the U. S. A. Hungarian data in 1960 showed similar levels to .... mthe U. S. A. The 1959-60 data published on levels in Canada were about5 ppm. It is of interest to note that in the European and American groups, iover 60% of DDT is present as DDE while in Israel it is about 54% and in •India 35%. Besides DDT, the detection of BHC has been reported in the fat
i
of people in the U. S. A., France, India and England and dieldrin in people
of U. S. A., England, Indi&. i
Conclusioni
Martin and Duggan reported on the pesticide residue in the total diet Hof U. S. citizens in the large cities and stated that there was no signi-ficant difference in the dietary intake using the three reporting periods iof June, 1964 to April, 1965; June, 1965 to April, 1966; and June, 1966 to iApril, 1967. The calculated levels were not seen to beapproaching theacceptable daily intakes established for certain pesticide chemicals by theWorld Health Organization.
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l Dr. D.A. Barnum,Chairman, Dept. Of Veterinar_
Bacteriology,
I Ontario Veterinary College,University of Guelph.
I MICROBES AND PUBLIC HEALTHHistorical Review
l Pre 1880 - Most early concepts of disease were "demonic" in that demons weresupposed to bring sickness so it was natural that many methods to ward off or appeasesuch demons were involved. However, there was evidence that certain conditions as
l leprosy and plague were recognized as being spread from to Some modernperson person.
writers have assessed many Of the writings in the old testament and a nulber ofreligious laws were based on practices to control disease.
| "About 1825 - There was great stress on foul air as being the cause of contagious
disease. This arose in part due to the fact that dead animals and corpses soon became
i fowl smelling. The stress by medical authorities on the pure air at that time is nowbeing reported in our concern for air pollution.
It was during this period that organized Public Health was born through the
l activities of Edwin Chadwich in 1844. He realized the need for regulations and inspec-tors to clear up the filth that contributed to the disease.
I 1880 - 1940 - About this time the founders of microbiology were making theircontributions.
Koch - established definite evidence that a bacillus could cause anthrax and the
I organism recovered.
Pasteur- the Father of Bacteriology initiated among many things immunization and
I pasteurization.
Lister - utilized the findings of Pasteur to establish aseptic surgery and stimu-
i lated the interest to antisepsis and disinfection.Following the establishment of bacteria and other agents as the cause of infectious
disease, the discipline of Public Health became established throughout civilized
I countries. Regulations at all levels of came into force of which aregovernment many
on our statue books unchanged. The various areas of Public Health developed as PublicHealth Nurses, Inspectors, etc., auxiliary forces to accomplish the task. Thus by the
I outbreak of World War II, those countries involved were able to combat a war knowingthat the outcome would not be influenced by outbreaks of contagious disease as had0ccurred in previous conflicts.
l 1940 - 1960 - Three important areas of development in the 1940's had profound in-fluence on microbiology and Public Health.
I (i) Discovery and Production of Chemotherapeutic agents
With the production first of penicillin, then other antibiotics and the sulfa
I drugs, medical science had available agents that destroyed bacteria in the host. Deathrates due to bacteria which were being loweredby control measures now plunged to thevirtual elimination of infectious disease as a significant factor in social life° By
i 1957 deaths from tuberculosis fill 10-202 of what they were in 1946 due to chemotherapy.
m 83
(2) The controlof insectgborndiseases,as the mosquitoborne malaria, througheffectivepesticidesby 1950, reduced the disease in some regionswhile in others asU.S.A.,it was banished.
11
(3) The ability to grow viruseson living cells (tissueculture)in test-tubeshas_led to effectivevaccine againstsome virusesdiseases. Notably, the salk vaccine for
poliomyelitis. I1960 + - While the historicalrole of microbes in Public Health is one of the mostinterestingof all medical history our purpose is to assess the situationtbday,
Our world is confrontedwith over populationand marked urbanization.The problems Iof today and tomorroware different. Some examplesthat Will be consideredare:
o.
(I) Resistance of microbes to drugs I
(2) The relationship_of a bacterial population to the human Or animal populationi
"ecology". The survival of bacteria'in the tissues of the host where it lives in har-
mony as the typhoid bacillus in a "carrier" person. •
(3) Greater concern of the n0n-contagi0usdiseases such as boil, urinary tractinfections. _
(4) The resistance of the host to disease--immunity--immunology as a science has •advanced m0st rapidly since 1960. |
(5) An attempt to understand how the products of the bacteria affectmetabolicactivity of the host cells to produce disease,
Microbes Other than ,Agents of Disease
Although this week we shall be considering bacteria primarily in relation to •
disease and food spoilage, the discipline of microbiology is now a major contribution |in science and life.
(1) The microbe is an organism that contains within itself the ability to utilizefood from the environment togrow and.repr0duee.. The bacteria are an excellent biolo-gical tool.for study.of genetics and cellular metabolism.
III
(2) Bacteria have possible potentialin sanitary conditions as they would be used Ito convert_waste industrial products to simpler compounds that can be used.
• !(3) Bacteria may have a potential in production of proteins from unusable materials
e.g. corn cobs or other fibrous material It is known that the micro-organisms of thebovine rumen are able to utilize cellulose for conversion into Usefulconstituents.
|Public Health
Ther_ are a number of methods of showing the different areas of Public Health. •One such method_showsi0 areas. "
i. General 4. Social Hygiene 7. Sanitation •
2. Statistics 5. Industrial Hygiene 8. Nutrition |3. Communicable Disease 6. Dental Hygiene _ 9. Vet, Hygienei0. Medical Zoology. Zoonoses
|The areas 3, 7, 9, 5 and 10_are the important areas. The microbes have varying
degrees of significance as: "
" I1. Agents of Disease (within host) •2. Spoilage of Food
3._Produce toxic substances in food - (botulism)4. Nuisance
value - growth of algae in swimming pools I
84 !
I Two films entitled the Harmful Effects of Bacteria and the Beneficial Effects ofBacteria serve to highlight the relationship of these organisms to Life.
I Description of Micro-organisms
The term micro-organism is used to include microscope living things. For the most
i part, they are unicellular and are able to carry out all necessary metabolic functions.There are an unknown number of microorganisms many of which are unnamed and unre-
cognized. It is stated that only i/i0 of the different types of bacteria in the intest-
I inal tract of animals and man have been identified.
Micro-organisms can be placed into one of seven groups--
l i. Bacteria, 2. Fungi, 3. Algae, 4. Protozoa, 5. Richittsiae, 6. Chlamydia, 7. Viruses.
Rickettsiae -- small pleomorphi_coccobacillary forms that have their habitat within
l cells and survive but briefly outside animal cells
Natural hosts are mammals and arthropods the latter serving as vectors and reser-
I voirs.
They are the size of small bacteria. Organisms in this group cause Typhus fever
I and Q fever and others. Q fever is not spread through an insect vector.Chlamydia (Bedsonia) -- Psittacosis - ornithosis group
l will filters that hold back bacteria, survive insideMicro-organisms pass through They
cells and have not _een cultured in cell free medium. Organisms in this group cause
Psittacosis (parrot fever) lymphogranuloma venerum.
l Protozoa -- These are micro-organisms often referred to as parasites but usually
microscopic having a size comparable to a red blood cell. Most protozia ingest solid
I food and digest it intracellular!y. Actively motile, few species as Plasmodium thecause of malaria are pathogenic for man.
Algae -- Simple single cell organisms but contain chlorophyll. They are capable
I of photosynthesis. A large group of free living organism found in almost all placesof the earth. They form most of the free floating microscope life in water called
plankton.
l GONOCOCCUS
l The disease gonorrhoeae has been recognized as a veneral disease for many centuriesin fact one of the earlier diseases recognized as contagious. At one time, it was
confused with syphilis.
! .By 1900, the organism--gonococcus was well described and its culturecharacteristics known are:
(1) Organism only affects man
I (2) Transmitted by intimate contact of mucous membrane(3) Rarely affects organs other than genital(4) Carrier person develops
l (5) Survival outside body for very short time, most susceptible of all organismsto environment.
1900-1939 - Disease moderately controlled.
I Two reasons--i. Public Health reporting of cases2. Moral standards - relatively high
|1939-44 - increase but controlled •
Io Greater promiscuity •2o Marked education on prevention I1945-1960 - Control by
io Treatment of penicillin
1961 - present - Disease out Of control for 3 reasons: IE
i_ Resistant strains
2o Greater promiscuity •3_ Birth Control pill I
Epidemiology
New Cases -- 1o In UoSoAo - teenager infected veneral diseaseevery 11 minutes
2 In U.SoA. - 2,000,000 cases II
Diagnosis - io Easy in male - smear culture, F.A. method
2o Female difficult - non symptomatic. •I
Public Health Inspectors
i° Not sanitation or environmental problem2. Bacterial disease - source and method of spread known
3o Control - io Identification of source and attempt treatment
2. Education to teenagers •3. Moral Standards° I
STREPTOCOCCUS IComplicated group of bacteria with the following characteristics:
chain of cocci •grow onlaboratorymediumo
Haemolytic- IClassified Group A - Man
B - Cattle
C - Animal and man •D - enterococci B
G - dog and man
IL. Strepo - throat streptococci'inman, eog. host specificity
St__tococcal Diseases - Man (Group A)
|Man - Scarlet fever, strep° sore throat, rheumatic fever, kidney damage.
Source - man I
Spread - Direct - aerobes
i Streptococcal Diseases - animals
i Group B - Mastitis str. agalactiaeC - horses strangles
- man sore throat (differs from strangles)
- guinea pigs - chronic lymphadentits
I Enterococci - Faecal streptococcipresent in large numbers in animals and man
I found in early stages in intestinal tractCharacteristics - I. Does not multiply outside body
2. Acid resistant
l rapidly outside body3. Counts decrease
Two Important facts:
l i. Used as an indication of faecal contamination2. Cause of one type of food poisoning
3. Enterococci of swi_e, bovine, horse and man appears to be
l a different species for a specific animal species, i.e.Str. bovis is the enterococci for cattle
Enterococci Counts used as:
l i. Index of Water Pollution2. Index of History of Frozen foods
3. Index of Spoilage Potential
!i. Enterococci some advantage over E. coli -
l a. Does not multiply in watersb. Disappears rapidly in streams and lakesCo effective supplement to coliform index
I 2. a. Enterococci persist longer than E. coli in frozen foodsb. Enterococci counts used to assess frozen foods prior to freezing
c. More heat resistant will survive some pre-cooking
!MICROBIOLOGY AND PUBLIC HEALTH
! •1. Communicable Disease - ***2. Sanitation - ***3° Veterifiary Hygiene,
l Zoonoses - ***4. Industrial Hygiene - *
I *Rate of Importance
MICROBE CLASSES
i i. Bacteria: Typhoid fever, Anthrax2. Fungi: Ringworm, Histoplasmosis
3. Rickettsiae: Typhus fever, Q fever
I 4. Chlamydia: Psittacosis5. Viruses: smallpox6. Protozoa: Malaria
I- 7. Algae: Algar poisoning
I 87
CHARACTERISTICS OF_MICROBE CLASSES i
i 2 3 4 5 6 7 IGrow in Lifeless Media + + ..... +
Does grow in Host. + + + + + + '- I
Survive in nature + + - - + - +
Observedwith light microscope + + - + - + + I
Important to Public Health Inspectors, +++ + +. + Jr+ - +_
i' l
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l
iiiI
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ii
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I DR. D.A. Barnum,
Chairman, Dept. of Veterinary
i Bacteriology,Ontario Veterinary college,
University of Guelph.
I DISINFECTANTsAND MICROBESr
I The role of disinfectants in Public Health has a long and vital history, butthere has been little research carried out to ensure the validity of many currentpractices. As confusion arises as to the precise meaning of terms Used in disinfec-
i tion and sterilization, the following definitions are given.Sterilize and Sterilization: -- any process, physical or chemical, which will destroy
all forms of life, applied especially to micro-organisms including bacterial and
l mould spores, and the inactivation of virus. The terms andsterile, sterilize
sterilization thereforerefer to the complete absence or destruction of all organisms
and should not be used in a relative sense. An object Or substance is sterile or
I nonsterile; it can never be almost sterile.
Disinfectant: -- an agent that frees from infection; usually a chemical agent which
i destroys disease germs or other harmful micro-organisms (but not ordinarily bacterialspores): commonly used as substances applied to inanimate objects. The legal defin-ition is more involved and states that if the intended use is against an organismforming spores or a virus, then the spores too, must be killed and the virus inact-
I ivated.
Germicide (microbicide): _L an agent that kills the growing but not necessarily the
l resistant Spore forms of germs; in practise a germicide is almost the same thing asa disinfectant but are used for all kinds of microbes and in any place.
i Bacteriocide_ fungicide, cirucide and sporicide: -- are agents that kill bacteria--fungi, viruses andsporesrespectively.
Antiseptic: -- is a substance that opposes sepsis, putrefaction or decay by preven t-
l ing or arrestingthe growth or action of micro-organisms either by inhibiting theiractivity or by destroying them; used especia!ly of agents applied to living tissue.
l Bacteriostasis: -- refers to a condition in which the growth_Qf bacteria is prevent-ed (adj_ bacteriostatic). Similariy fungistatic describes an_agent that stops the
growth of, fungi ........
l Sanitizer: -- an agent that reduces the bacterial count to safe levels as may bejudged by public health requirements on foodehandiSng_equipment, eating and drink-
ing utensilsandthelike ....
I Antibiotic: -- a substance produced by micro-organisms which has the ability evenin dilute solutions to inhibit the growth or destroy bacteria and other micro-organ-
isms; used especially in the treatment of infectious diseases_of_man, animals and
l plants.
The definition of various other terms requires little clarification i.e. the
I suffix "cide" indicating a "killer" or "stat"meaning "inactivation" or "inhibition"of growth.
!I 89
lSites of Activity i
The bacterial cell has a number of structures that are involved in the killing ior inhibiting process. They are the cellwall, the cell membrane, the protoplasm(protein) and;the enzymes.
i
This activity was demonstrated by visual aids to show the select sites, i
The common disinfectants were discussed in relation to their specialized activity iand their
stability in relation to organic matter, l
(i) Alcohols are toxic to cells at relatively high concentrations_and act as
protein coagulants. I
(2) Phenols at the high concentration usually employed (I-2%) coagulate proteins.i
_ (3) Heavy metal ions as Mercury and silver (mercurochrome) act on enzymes but iare readily inactivated by organic matter.
(4) Oxidizing Agents: chlorine, iodine act on enzymes I
(5) Detergents sterilize by disrupting the cell membrane, presumably through
c0mbining primarily with its lipids. This mechanism explains why detergents are •
less active against those viruses that lack a lipop_otein surface membrane than againstthose possessing such a membrane.
(6) Heat applied to cells acts by the coagulation of cell protein. There is a Ivariation in the susceptibility with spore formers being resistant requiring steamunder pressure, staphylococci requiring up to 80°C while coliforms are heat sensitive.
(7) Radiation--Ultraviolet light action is due to production of peroxides in the lmedium, which in turn acts as an oxidizing agent. As light passes in a straight line,
this form of sterilization is rather unsatisfactory. _ •i
Gamma radiation have been applied to the sterilization of food. It is effec-
tive in killing the bacteria but may induce undesirable effects on flavour. •
In recent years, the use of ethylene oxide, a highly water-soluble gas is
used for dry disinfection, especially heat-sensitive objects--plastic ware, surgicalequipment hospital bedding, books, lether etc., handled by patients. _ The•use of the i
material in ampules to use in plasticcontainers may have practical importance.
emphasis. In practical disinfection, a few points of disinfection kinetics require i
(i) There is a time-dose reiationship in all cases, The smaller the dose, the i
longer the time required for killing the bacteria. This also indicates that when •
the bacterial contamination is a factor as one concentration would destroy a smalli
number of bacteria more rapidly than a large number.i
(2) The death of any bacteriai population follows a death curve. Thus in any i
sterilization, fewer organisms are present as time progresses. Thus it is difficult
t0 ensure i00% elimination Of the organism. The concentration of disinfectants and •the time suggested represent a practical approach. l
l9o I
DR. D.A. Barnum,
Chairman, Dept. of Veterinary
l Bacterio!ogy,Ontario Veterinary College,University of Guelph.
I Principles of Food Infections and Food Poisoning or Intoxications (i)
l Food infection implies the transmission of infectious agents through food toman or animals, thus microorganisms are involved. Food poisoning or intoxicationsimplies that the food contains toxic substances that cause illness.
I a few instances, food poisonings are also food infections, e.g. salmonellosisIn
or Clostridium perfringens food poisoning.
I Food Poisonings - This may result from a diverse group of agents. Some people usethe blanket term "ptomaine" a term that is unscientific and meaningless.
I Although food may be poisoned with chemicals or poisonous plants, e,g. arsenicor toxic mushrooms, we are concerned with a toxicity due to action of micro-organisms.The organisms involved are of bacterial, fungal or algal origin.
I In order for poisoning to occur, there must be (a) the organism plus the rightconditions for production of toxin and (b) Ingestion of toxin.
l Requirements for Production of Toxin
(i) Toxigenic strain - e.go Staphylococcus
(2) Proper medium for growth and production of toxin
(3) Incubation time for production of toxin
(4YStability of toxin,
l Requirements for Ingestion
(I) Toxin present in an edible food. This is dependent upon condiflions but in
l genera! should hot be associated with putrefaction.(2) Must be a susceptible host; e.g. staphylococcal enterotoxin only toxic for
E monkey, man and kittens.(3) Toxin must be absorbed from intestinal tract.
R Mycotoxins (2)
It is not surprising that some fungi produce toxins when they do produce toxic
i substances for bacteria in the form of antibiotics. The toxins from fungi are calledmycotoxins. Al_hough there are a number of these, one is of current interest--theaflatoxins.
l Aflatoxins are produced by certain strains of Aspergillus and Penicillium whengrown on crops or Pr0cessed food. It has been found in the following foods--peanuts,
wheat, rye, soy bean, buckwheat, corn, rice, egg noodles, cheese, condensed and
l powdered milk, hazel nuts, brazil nuts, poppy seed, coconut, apply juice, apples etc.
m 91
|In the laboratory, shredded wheat to which water is added and autoclaved makes •
excellent medium for the support of the fungus and growth of toxin°
Toxigenic strains produce a toxin in 4 - 7 days at 28-30 °. Temperature and imoisture are essential requirements. For growth in nuts, the sheelmust be broken°
Toxin affects the liver of mammals, birds, and fish. Susceptibility to the toxin i
varies with_age, with the young being more SUsceptible.i
The young duckling is most susceptible species and it is also used for laboratory n
testing.
The susceptibility of man to this toxin is not established. Undiagnosed illness •has been attributed to food which contained toxinproducing Aspergillus. nMethod for Detection of Aflatoxin Poisoning
(i) Collection of mouldy food
(2) Isolation of fungi Bi
(3) Growth of organism on suitable laboratory medium
(4) Demonstration of aflatoxin by chemical methods or biological methods n
OR
The demonstration of toxin in original product can be attempted, i
Recent studies at the Food and Drug Directorate, Ottawa showed that 16 of 129 •fungi isolated from 74 food samples had the ability to produce toxin. These came mfrom meat pie, apple squares and spaghetti (dry), orange juice, coca (powder), ham,
cheese, instant chocolate (powder), rice (T.V. dinner), hops (brewery), grain used n
for animal feed and brazil nuts. i
Botulismn
Botulism is caused by a toxin produced by Clostridium botulinum. The toxin is mproduced outside thebody and the organism is not associated with the host. The
spores of Clostridium botulinum are highly resistant to heat and require steam under •pressure for their destruction. The spores germinate only in the absence of air. |They will grow over a wide temperature range 20-37°C and ideal growth occurs inmedium of high protein content. The toxin is released from the bacterial cells as
the cell dies° i
The conditions suited for production of the toxin can be found in vacuum packed
meat(an anaerobicenvironment with protein), nN
The toxin is absorbed from the intestinal tract and affects the function of nerves
causing paralysis. This is evidenced by muscle relaxation. Muscles of visionand •
respiration are affected. A small amount of the toxin is capable of exerting symptoms iand once symptoms are observed, there is no effective treatment.
The toxin is readily destroyed by boiling for i0 minutes° There are 5 types of nbotulinus toxin. Types A, B and E are toxic for man. The spores of type E have been
i
isolated from_mud and fish from the Great Lakes, the West coast of Canada and a fewtimes in the Gulf of Maine. •
m
92 |
I Botulism has received increased attention recently due to deaths from cannedfish in U.S.A. and canned liver paste in Canada.
J Staphylococcal Food Poisoning
i This is the most common type of food poisoning. Certain strains of Staphylococcusaureus are capable of producing a heat stable enterotoxino when grown in milk and
meat products. The organisms will not grow at refrigerator temperatures, but require
a temperature of 50°F to produce the toxin.
I The source of the organism is either from the human carrier or the bovine mammary
gland. In the former case, the organism may be in the nares ( a healthy carrier )
l or from an active lesion. In the second instance, S. aureus does establish in manybovine udders where it produces a chronic mastitis. Many strains are enterotoxin
producers.
l conditions are ideal, the toxin will be produced in the beingandIf food heat
stable will survive even when e.g. the milk is pasteurized, powdered or the food iscooked.
l Investigation of such outbreaks require securing the suspected food. The pre-
sence of large numbers of S. aureus is a strong indication of the source. The
I carrier may be sought and identity of the staphylococci compared by phage typing.There are new methods for the isolation of the toxin from food and its identi-
fication by serology methods. Twenty gms° of food material is required to process
I for this test. It has not been developed at this time for routine use.
€_. perfrin_ens in Food Poisoning
l Vehicle is almost always meat. Contamination of the meat occurs prior to cooking°
Spores are not killed by cooking, but activated to sporulate. It grows in meat where
i an environment free of oxygen exists. Large numbers of actively multiplying organ-isms appear to be necessary for food poisoning. The time interval between comsumption
of the food and appearance of the symptoms varies from 8 to 24 hours. Diarrhoea is
the prominent symptom accompanied by abdominal pain without vomiting or headaches.
I Volunteer experiments have succeeded only when the live organism has been activelygrowing in a meat medium.
l The diagnosis is based on:
(i) CI. perfringens present in numbers so that several hundred million
i cells are ingested.(2) Spores are heat resistant.
l (3) Type A CI. perfringens
Streptococci
R Enterococci, Streptococcus faecalis or Str. faecium. These organisms are partof the normal flora of the intestinal tract, but are potential pathogens outside the
i normal tract as urinary tract infection.Reports are associated with this organism being present in large numbers in the
food associated with food poisoning outbreaks.
!I 93
The association_of this organism with outbreaks has not been fully established, i
ConditionsRequired I(i) Contaminated food with faecal streptOcocci
(2) Incubation at room temperature is sufficient for rapid multiplication. I
REFERENCES I
(i) Microbiological Quality of Foods, Academic Press
(2) Mycotoxins from Food-borne fungi, Can. J. Micro. 14:131 (1968) i
i
I
ilI
iIIII
DR. DoA. Barnum,
Chairman, Dept. of Veterinary
I Bacteriology,Ontario Veterinary College,
University of Guelph.
I ESCHERICHIA COLI: FRIEND OR FOE OF MAN
I There is a group of micro-organisms known as coliforms which are able to fermentlactose with the production 6f acid and gas. Although, there are a number of speciesin this group, Escherichia coli is by far the most common and most significant.
I E. coli has received and does receive attention because: a) it is used as anindicator for fecal pollution of water and food products, b) it is part of the normal
flora of the intestinal tract of man, animals and birds; and in this situation, it
I may synthesize some vitamins and help to control the growth of unwanted bacteria°The organisms are found in the intestinal tract very early in life and remain through-
out. They are composed in man of resident and transient strains, c) E. coli is an
I mportant cause of disease in all animals and man. Young animals and children sufferintestinal infections with this organism, while in man and older animals, organs and
systems are involved, d) this organism has been studied_more than any other as a
I iological entity. Most of the understanding of cell functions, cell metabolism,genetics, and virus infection of bacteria have all been relatgd to it.
Since the organisms have a normal habitat, are associated with infections as
I emonstrated in the laboratory, one must ask the question as to whether all strainsof E. coli are the same. Thus, studies in recent years have given attention to theidentification of them.
I Identification of E. coli strains
E. coli possesses in its cell a number of antigenic substances which are related
I to the cell body, the cell capsule, and the cell flagella. These antigenic substancesvary on different strains and it is now known that there are 149 different O antigens,88 different K antigens and 45 different flagella antigens. Thus one is able to
I serologically type an E. coli strain which is illustrated as follows: 0138K88,HI5.It is possible to have varying combinations of the "O", "K" and "H" antigens. Thus,
_ one can see the tremendous possiblities of types. There is an International Centre
I n Denmark for the serological identification of strains so that a type found inthe United States can be compared to a strain found in Japan. These types are stableand under most circumstances do not change.
I In addition to serological typing, it is possible to identify strains by theirantibiotic sensitivity patterns, by their colicin type and by chemical tests. Thus,
it is possible to accurately identify strains. It is a complicated laboratory
I rocedure and is only done under certain circumstances.
Relationship of Serological.......T_pes to Disease
I •In recent years, attempts have been made to correlate certain disease syndromes
with serological types. Thus, in humans it is known that relatively few serologicaltypes are associated with infantile diarrhea. Laboratories maintain diagnostic
I antisera for these types and when a strain is recovered from a case, it is testedand if it belongs to one of the serious disease producing types, then control measures
are initiated in that hospital. One frequently finds a carrier of that strain among
I the hospital personnel or contaminating equipment and food. Not only are certain
|strains associated with diseases in man, but likewise certain types are associated i
with disease in animals. There are types that cause white scours in calves, air-
sac infections in poultry, enteritis in pigs, and diarrhea in lambs. It is inter- •esting that the pathogenic strains of pigs are not pathogenic to calves, etc. The
reason for this host selectivity is not known.
It has been possible to determine in animals by experimental infection of the isusceptible host, that certain types have pathogenic properties. One must use young
J
animals as there is a definite age resistance which means that a strain may exist
in the intestinal tract of man without causing any trouble but is pathogenic for the
infant. In animals, infection studies are carried out on germ-free animals or in isome cases, the organism is injected into an isolated intestinal loop of an animal.
A pathogenic strain causes marked accumulation of fluid within the loop. A recent iexperiment at the Ontario Veterinary College with porcine strains has contributed |new knowledge in this field. It has also been shown that an enterotoxin can be
prepared from E. coli cultures which produces the reaction. •
The specific types produce a specific antibody when they are injected into an
antibody producing animal such as the rabbit. This antibody is capable when mixed
with the organism in experimental infections to prevent the disease. It is for this ireason that it is important in certain animals such as calves for them to receive icolostrum from the dam which contains a high antibody level. In man, the infant does
receive the antibody through the blood stream in utero, but this is not the case withmost animals. This specificity means that when animals or children are moved toan nenvironment away from the mother or dam, then they will hawe contact with new
serotypes mgainst which they have not received the antisera. This emphasizes that n
the environment of the very young must be carefully controlled so that they are not •exposed to serotypes which have pathogenic significance. The strains may be in the
g
environment or contaminate the food.g
E. coli as part of the Noinnal Flora ' H
E. coli does not generally involve the upper part of the small intestine but mgrows readily in the lower portion and is found in large numbers in faeces of both ianimals and man. While man has the resident flora which means that relatively few
serological types will remain_in the tract for periods of four months or more. In
addition, there are transient flora which persist a relatively few weeks. These ikeep changing within the population and some of these may be pathogenic for infants i
and others may not.
A frequent E. coli infection of man in that of the urinary tract where these B
strains may be of many definite serotypes. It seems that if any type finds its way
into the urinary tract of a susceptible individual, it is capable of setting UP in- •fection with intense irritation. So a person may be carrying the organism in the iintestinal tract which is capable of causing disease in other sites of the body.
Antibiotic Sensitivity of E. coli. I
With introduction of antibiotics, it was soon determined that penicillin was
not active against E. coli as it is a Gram negative organism and in general, pen- •icillin was not active against Gram negative organisms. However, other antibiotics isuch as streptomycin, aureomycin were active against it and in the early days, all
strains were sensitive. This is not true today when most of the strains tested are i
very resistant tO most of the antibiotics. This change has been brought about by ithe use of antibiotics in many ways. Antibiotics in animal feeds have cohtributed
m
to the marked change in the sensitivity pattern, so much so that it is almost
impossibl_ to satisfactorily treat some of the neonatal diseases of calves and pigs i
l caused by this organism. E. Coli has the ability to develop this resistance and topass this resistance on to other bacteria through a process called sexual recombina-
l tion. Not only can it pass this resistance from one E. coli strain to another 9 butit can also be passed to a more serious organism such as Salmonella. This marked build-up of resistance of E. coli has therefore serious consequences to our enteric bacteria.
i Once a strain becomes resistant it maintains it for a long time. _E. coli Environmental Sanitation
l E. coli has long been an indicator for fecal contamination in water supply andthis will continue to be used as it is an excellent marker. The organism does mul-
tiply in water to some degree and has a long survival time. The tes_ now_ applied does
l not determine the serological type of the E. coli thus, one has no knowledge of thesource as to whether it is animal or human. In some cases, this might be useful
information and could be accomplished by serological typing if it was not an involved
l procedure.The presence of E. coli in food is an excellent indication of improper handling
in contamination. This is especially true in dairy and packaged food products.
i Again, it would be interesting to know the source of some ot the E. coli that onefinds under such circumstances.
l E. coli as a Cause of Food Poisonin$E. coli has been _ncriminated as the cause of food poisoning in man and results
i from contamination of food with a very high E. coli count numbering into millionsper gram. This type of food poisoning is difficult to reproduce and can only be
done in human volunteers. Experiments give a rather inaccurate results, but in
general consensus of opinion is that E. coli is capable of causing the disease. ' It
l is known that E. coli produces an endotoxin which is capable of producing a reactionwhen injected into animals and is associated with some conditions in man. Perhaps,
it is possible for this endotoxin to accumulate in the food and be part of the asso-
i ciated syndrome. Recent Studies have shown that certain animal strains have anenterotoxin, so perhaps this toxin may play a part in food poisoning.
It will be interesting to see what future developments occur in this field and
i Public Health to determine association of a food poisoningInspectors are urged any
outbreak with high coliform counts in the product.
l One must now consider E. coli more than a part of the normal flora of man.This organism which can be serologically identified is the cause of many outbreaks
of diseases especially in the young and perhaps in food poisoning. AS it is an
i organism that abounds in our environment_ Public Health Inspectors must always beaware of its significance and control.
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!
|Dr. D.A. Barnum, mChairman, Dept. of Veterinary
Bacteriology, iOntario Veterinary College,University of Guelph.
LEPTOSPIROSIS B
Leptospirosis is a disease of animals and man caused by one ofthe species of the Genus Leptospira.
These organisms are very fine and can be seen by the ordinary mmicroscope. Isolation is difficult to accomplish and usually labora- |tory animals must be used in this regard.
The different species are found with varying frequencies in dif- lferent countries. Leptospira icterohaemorrhagia a disease of rats and ......•....spread to man is rare in Canada. Also Lepto. canis, a disease of dogsspread to man is uncommon. Lepto. pomona _s the most common in Canada •and many countries. _"
The habitat of L. pomona is in wild animals as skunk_ racoon, and agroundhogs. In these animals, the organismsurvives where it localizes |in the kidney and is shed into the environment via the urine. In theseanimals, it does not cause any symptoms or lesions, neither does thebody produce antibodies against it. In mostcases, the organisms dievery quickly outside the body as they are susceptible to the dry state gand acid environment.
!However, surface water of ponds and streams provide a stabilizingenvironment. Thus streams may be the source of infection for domesticanimals and man.
Due to their small size, the organism will penetrate the unbroken •skin. They invade the blood stream. This invasion may--
(a) cause a generalized infection With fever, anaemia and an acute Iillness. This is especially the case in calves where the mortality is
high. l(b) involve the gravid uterus of pig and cow resulting in an
abortion, in such cases, there isno serious illness in the dam. Out-breaks involving a number of animals in a herd occur usually in late Isummer and fall where most of the females pregnant in the lather part
i
of gestation abort.
(c) localize in the kidney and cause a nephritis. In these cases, Ithe organisms arel shed in the urine. The infection persists for i-2
months in the bovine but much longer in the Pig.
It is from the last c0ndition, that manmay be accidently infect-ed. Fortunately, the organism dies quickly in the urine of the cow
and pig. l
Leptospirosis of man is a more serious disease in warmer climateswhere there is a greater contamination of water and where human types ofthe organism are more prevalent.
98
l DR. D.G. Ingram,
Ontario Veterinary College,
l University of Guelph.
l Body Resistance to MicrobesThe science of Immunology had its origins in the realization that persons who
recover from an infectious disease are unlikely to suffer a second attack of the same
l isease. This observation was made in ancient times and in epidemics of the past,it was used in selecting people who might safely nurse the sick.
l In the 18th century, the experiments of Jenner provided the basis for a generalapproach to the problems of preventing infectious diseases. Jenner demonstrated
that cowpox virus could immunize man against the disastrous effects of smallpox virus
infdctions. The term vaccine is thus derived from the latin "vaccinus" meaning "of
l cows" the latin "vaccinia" -through cowpox.
About i00 years ago, Pasteur applied similar procedures and there was a rapid
l development of vaccination against anthrax, cholera of chickens and rabies in man.
Near the end of the last century yon Behring and Kitasato demonstrated the
l usefulness of antiserum in the treatment of infectious disease of man - diphtheria.At about the same time Metchnikoff was developing his theory of cellular immunitywhich maintained that immunity to infectious disease was due to the activities of
l phagocytic (eating) cells.Thus at the start of the present century, the basic ideas and principles ofimmunization to infectious diseases were well established. Since that time we have
l become considerably more sophisticated but the basic principles remain.All higher vertebrates - from fish to man - possess physiological mechanisms,
l he function of which is to detect and eliminate from the body any substance thatis not a normal component of the healthy tissues.
These two functions of detection and recognition have a considerable overlap
l ut for convenience we can divide them for our initial considerations.Detection - This involves the recognition of the invading microorganism or substance
as foreign.
l When the individual is first exposed to a disease producing organism, by naturalcontact or vaccination or other forefgn substance, certain cells scattered throughout
l the body recognize these as foreign. The cells involved in this recognition arebelieved to be the small lymphocytes - one of the white blood cells. In normal man,
they number 1000 to 3000 per cmm Of blood - or it is estimated that in a normal man
f x lO"new lymphocytes are produced each day. These cells are present in all
I tissues of the body as well as in the blood and occur in very large numbers in thelining membrane of the throat and bowels. It is considered that each small lymphocytecarries the information or has the ability to recognize one or two foreign chemical
l groups - antigens.What happens when this small lymphocyte comes in contact with a substance, or
a microorganism which it recognizes as foreign? Two things happen:
l . the cell is stimulated to reproduce more rapidly than normal and soon - withina few days - there are a large number of daughter cells - asexual reproduction gives
a number of cells identical to the original - a clone - all of which can recognize
l the same foreign substance and can react against this substance,
l 99
i2. Some of these daughter cells change andmature into plasma cells. In this process
the cells produce antibodies which are liberated into the blood plasma. These anti-bodies are proteins, of a type known as gamma globulins, and they too are able to •recognize and can combine specifically with the foreign substance. Once a cell has
i
matured into a plasma cell, it can no londer divide - it produces antibodies for some
time and when it is worn out it is eliminated from the body. ii
Secondary Responses
On second exposure to the same microorganism or foreign substance the same type of iresponse occurs but it happens much more rapidly and the antibodies produced reach a Rmuch higher level. The latent period for primary exposure is usually about 8 to 10 daysbefore antibody appears in the serum. But on secondaryexposure the latent period is
reduced to about 3 to 5 days. This secondary response is why most vaccination programs •involve a series of injections. i
Elimination - The cells which are largely responsible for the destruction and elimin- •
ation of microorganisms or foreign substances from the body _re those of the Reticulo-
endothelial (RE) system. These cells comprise some circulating white blood cells- the
polymorphonuclear leucocyte and the macrophage - and a large number of fixed cells iwhich occur in many tissues but primarily in the liver and spleen. The characteristic Bof these cells is their ability to ingest and digest foreign or worn out materials.They are called "Phagocytes" - eating cells.
m
These phagocytes, then, are able to ingest or engulf microorganisms or foreign B
substances. The cells in the liver and spleen, etc. are situated strategically in theblood stream so that they come in contact with any foreign material in the blood and U
are able to remove microorganisms etc. from the blood which flows past them. These |cells contain a variety of enzymes which are able to kill and digest the organismswhich they engulf. iMechanisms of Pathosenicity and Protection i
Various microorganisms have different means of producing disease.m
Some bacteria produce disease by getting into the body and multiplying extensively. _iAn example of this type is the pneumonia caused by the Pneumococcus. These organisms
produce a large capsule which enables them to resist being engulfed by phagocytes. Whenantibodies are produced against this capsular material, the antibodies combine with |the capsule and make the organism susceptible to phagocytosis. Antibody makes thepneumococci more appetizing for the cells of the RE system.
• !Other bacteria produce exotoxins. These are toxins or poisons which are readily
separated from the microorganisms which produce them. Thus the tetanus bacteria may belocalized in a wound in the foot but its deadly effects are produced by an exotoxin •which reaches the central nervous tissues and causes disease by interfering with the mmessages being passed from nervesto muscle cells, thus causing paralysis. In thisdisease, antibodies can neutralize the toxin and thereby prevent the disease without ' inecessarily interfering with the survival of the bacteria in the wound. Other dis- Beases caused by such exotoxins include diphtheria, gas gangrene, botulism.
Some bacteria produce disease by means of endotoxins. These are poisons which Bare a part of the bacteria themselves and only become separated by the death and
m
disruption of the bacteria. Examples of this type of disease includes cholera and
Escherichia coli infections of the newborn. Antibodies are not very effective against •this type of disease and vaccination or immunization programs are of doublful value.
Endotoxins are very resistant to heat and therefore merely heating a solution doesnot destroy its endotoxic activity, i
B
100 i
!Other microorganisms cause disease by actually invading living cells. Viruses,
as a group, can only survive in living cells and they change the metabolism of the cellso that, instead of producing cell components, the cell is forced to produce virus. This,
of course, leads to the death of the cell and unless the cell is replaced, it willeventually lead to the death of the host. The classical example of this type of disease
is poliomyelitis. The polio virus invades the central nervous tissue and causes thedeath of nerve cells. Since nerve cells cannot be replaced, the muscles which are con-
trolled by the dead nerve cells become paralysed. When this happens to the muscles which
are responsible for breathing, the patient must be placed in an artificial lung or hewill die from lack of breath.
Fortunately, antibodies can neutralize or destroy the polio virus provided theantibody can react with the virus before the virus gets inside of a nerve cell.
Microorganisms have developed many devious ways of producing disease, and in res-
ponse, the body has cleverly developed several methods of dealing with microorganisms.
The normal fluid of the blood and tissues contains a number of substances such as
lysozyme, properdin, conglutinin, bactericidin, beta lysin, etc. which kill bacteriaor other microorganisms. These substances are sufficient to prevent invasion of thebody by mostmicroorganisms. In spite of these bactericidal substances, some micro-
organisms manage to invade and survive in the body. When this happens antibodies areproduced, and these neutralize and eliminate some invading microorganisms. Sometimes
the antibodies work in conjunction with phagocytic cells of the RE system to bring
about the destruction of virulent, invading organisms. Occasionally the phagocytes can
engulf and kill microorganisms without any aid from antibodies --- but antibodiesgreatly enhance their activity.
Sometimes either antibodies are not produced or they are ineffective in destroyingthe organism. An example of this type of disease is TB. In this case, the infected site
is surrounded by manycells of the lymphocyte type and the cells themselves react
against the microorganism. This leads to a walling off of the TB organism in nodules
and the organism survive for many years in these nodules in a balanced state withoutmay
causing clinical disease. This type of immunity is often refered to as cellular immunity.
SummaryTo protect the body against infectious disease we have (i) the physical barrier ofthe skin or mucus membranes (2) the normal bactericidal and virucidal substances in
blood and tissue fluid (3) the ability of phagocytes to engulf and destroy organismswhich manage to get into the body (4) the ability to produce antibody which may actdirectly on microorganism or may act in conjunction with phagocytes and (5) cellular
immunity where lymocyte-type cells react against invading organisms in a manner which
is not completely understood.
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!ioi
lDr. N.A. Fish
Ontario Veterinary College m
University of Guelph l
Salmonella - A CUrrent ProblemIm
The term sa!monellosis is commonly used to describe infections produced by any of I
the numberous numbers of the genus Salmonella. The genus is composed of some 900
recognizable serotypes which have been isolated from many species of wild and domestic •animals, from man, and from their environments. Aside from a few serotypes such as lSalmonella typhi of man and S. pullorum of fowl, which have a marked host preference,the salmonellae colonize all species of warm-blooded animals with a similar degree of
acceptance, l
The most severe illness produced by salmonellae occur in the new-born and
debilitated individuals e.g. severe and fatal outbreaks which have been observed in •obstetrical nurseries and fatal bacteremias in older persons during the course of a
terminal illness of after surgery. Stress is a significant factor in producing illness
in animals and poultry. I
The most dramatic and highly publicized aspects of salmonellosis are the foodborne infections which occur in large groups of persons that have consumed a contamin- i
ated common food, prepared and held under conditions conducive for growth and multipli- •cation of organisms. Such occurrences result in extensive and often severe outbreaks i
of infection among those persons consuming the infected food. The incubation periods of
these infections usually range from 8 to 48 hours. The usual symptom is a febrile •gastroenteritis, which persists for 24 to 72 hours. |
The major reservoirs of human salmonellosis are poultry, domestic animals and i
human carriers employed in food handling duties. Salmonellae are common in poultry, i
not uncommon in cattle, calves and pigs, sporadic in sheep and horses, frequent ini
rodents and turtles and occasional in various wild animals. Salmonellae have been found
in snakes, lizards, tortoises, flies and cockroaches. Ii
With the high rate of salmonella infections among animals, it is observed that
many foods of animal origin frequently contain salmonellae. In addition, to the long •recognized problem in poultry, red meats and egg products, recent reports have appeared lconcerning the presence and spread of salmonellae in soya milk, dried yeast, coconut
and cereal powder. Salmonellae are also present in a wide variety of animal by-products
including bone, liver and lung, blood, feather and fish meals, and complete feeds, i
Although salmonellae are widely distributed in animals, animal fee_s and human
food products, the importance of the human carrier in the transmission of salmonellosis •must be considered. Studies have demonstrated continuous or intermittent excret&on
of one salmonella type for long periods of time in specific individuals. In most
instances, people excrete salmonellae for a period as short as two to three weeks mafter infection. In various surveys, it has been noted that from 15 - 30 per Cent lof salmonella cultures isolated from man were derived from asymptomatic persons. Aconstant carrier rate in the general population is estimated to be from two to 50
per thousand. It is sometimes difficult to evaluate whether the food handler is the •
source of infection or has been infected from the same source as the victims. Many m
of the recovered cases develop into human carriers.
II
lo2 |
DR. N.A. Fish,•
• Ontario Veterinary College,University of Guelph.
I Changing Patterns of Microbes
"Bacterial organisms, like other forms of plant and animal lifechange with the environment in order to survive and propogate. Sincetheir growth and multiplication is rapid, this adaptation may occur with-
l in a short period.In the consideration of these changes, some appear to be beneficial
i to mankind while others are harmful and create severe problems in diseasetreatment and control.
io Change in pathogenicity_- a) Brucellosis - In the study of con-
I trol measures of this disease which affects man and animals, Strain #19Brucella abortus isolated from a field case•of the disease has beenpropogated. _ It has served as the source of an_attenuated vaccine to
I aid in the control and eventual eradication of the•diseaseob) Erysipelas - A severe acute disease involving swine can be controlled
i by vaccination of pigs with an attenuated strain.c) Rabies - An attenuated rabies virus vaccine produced from sterilepig kidneys is proving to be a highly effective agent for protecting
l livestock, and other animals from rabies.d) Oral poliomyelitis vaccine - attenuated strain of poliomyelitis virus.
I e) German measles vaccine - attenuated strain of rubella virus°
2. Change in virulence of organisms - a) Strains of S. aureus
l producing systemic infections in poultry which previously producedno significant lesions° b) Highly virulent strains•of Corynebacteriumdiphtheriae are more potent toxin producers, consequently are ideal for
l toxic production° Many strains of Corynebacterium isolated from the _throats of persons have a low virulence or are non-pathogens. The changein virulence may be associated with bacteriophage, a virus like agent
l that grows in conjunction with the organism.3o Change of identification of bacteria -•Some species of bacteria
may change within a group and produce subtypes or serotypes e.g. Lepto-
i spira Salmonella typhimurium. The subtype or serotype may bepomona,
less pathogenlc and produce cultural changes different from the isolate.Bacteria can produce mutants which are selective growth of the parent
i bacteria.4. Bacterial resistance to antibiotics and chemotherapeutic agents -
l This phenomenon has been observed for some time, but unhil recently• theresistance trend was con<sidered a slow progressive change where bacteriaby mutation and selection would gradually become resistant° However,it is now established _hat transfer of drug resistance from one bacteria
l to another of the same or different species is infectious and occursby conjugation. Thus a spectrum of _antibiotic resistance can developwith bacteria carrying resistance transfer factors mediating resistance
I to as many as six drugs simultaneously°
!103
lDR. N.A. Fish, ms
Ontario Veterinary College,
University of Guelph. i
Meat-Borne Infections IThese infections may be divided into two groups:-
i. Parasitic +2. Bacterial & Viral •I
i. Parasitic
A. Tapeworms - taeniasis I
a) Unarmed tapeworm of man - Taenia saginata
This parasite is harboured in the intestinal tract of man and the ova are idisseminated via human wastes to pasture land. The ova once ingested by
cattle produces a cystic or larval stage identified as Cysticercus bovis i__ ; which locates in the masseter and heart muscles, diaphragm and intercostal l
muscles. It is readily demonstrated by macroscopic examination as a small
bladder like cyst or a calcified lesion depending on age. Cysticercus
bovis can be destroyed if the beef carcass is held at 15OF or below for Iten days. Meat heated to 140OF is adequate to destroy the cyst.
b) Armed tapeworm of man - Taenia solium I
The life cycle is similar to T. sa$inata except cystic age occurs in swine,
producing measly pork. The cystic stage, Cysticercus cellulOsae, occurs in i
the tongue and muscles, heart, diaphragm and muscles of thigh and neck. In •man the cystic stage may develop in skeletal muscles, heart, brain and eyes.
i
Freezing and cooking destroy the cysts.
B. Trichinosis - produced by Trichinella spiralis, a round worm which spends its l
entire life cycle in the body of the host including man. The pig is the food
producing animal which is heavily parasitize d . In the hog carcass the larg- •est number of trichina are found in the diaphragm, tongue, laryngeal, lumbar, Imasseter and abdominal muscles. Hogs become infected by the feeding of un-
cooked garbage, kitchen scraps or slaughter offal. The prevention and control i
of trichinosis is based on two principles a) Examination of the carcass by •a trichinoscope to ensure that it is trichina free. b) Carcass is rendered i
safe for consumption. Pork may be rendered safe from trichina by refrigeration ,
heat, and curing under controlled conditions, li
C. Fish tapeworm - Diphyllobothrium latum. The larval stage is found in the flesh
of pike, perch and trout in the region of the Great Lakes. The adult inhabits iintestinal tract of man, bear and wolf. Adequate cooking of fish is required lto destory larval stage.
2. Bacteria and viral li
a) Staphylococcal - previously discussed
b) Salmonellosis - previously discussed I
!lo4 |
I l I!c) Botulism produced by a neuroparalytic e_o_oxin due to the growth of Clos-
tridium botulinum. Types A and B are commonly the cause of illness due
I o the consumption of meats, while type E involves fish or their products.When toxin is produced in meat_ organoleptic changes are evidenced by a
putrefactive odour and gas production.
I The preventive measures of A and B are:type
i. Heat processing of canned foods in accordance with standards e.g. time
I nd temperature.2. Acid-preserved foods should have a pH no higher than 4.5.3. Refrigeration of perishable foods at temperatures below 45OF.
i 4. Hygienic practices to reduce spore contamination to a minimum.d) Clostridium perfrinsens - a spore forming bacteria which is a normal inhabi-
tant of the intestine of man and animals. The spores are heat-resistant and
, capable of withstanding boiling temperature for four hours. Where meatproducts have been heated at low temperatures and then remain at room temp-
erature, spores may germinate, producing profuse growth. Prevention consists
I of adequate refrigeration of meat products after cooking e.g._m_at pies.
e) Bacillus subtilis and cereus - These are spore-forming bacteria capable of
i roducing food-borne illness. Foods which have been heated and subsequent-ly remain at warm temperatures (75 - 80OF) permit spores to germinate. Toproduce illness, the organisms are present in large numbers at least several
million per gram of food. Turkey meat and sausage are foods that have been
I incriminated.
f) Enterococci - Streptococcus fecalis represents a member of this group which
I has produced food borne illness.Viruses - Poliomyelitis and other enteroviruses have been suspected of creat-
ing food borne illness. Shellfish have served as a vehicle in the trans-
I mission of the virus of infectious hepatitis.
I
III 105
iDR. N.A. Fish,Ontario Veterinary College,
University of Guelph. •i
Staphylococcus - Ubiquitous Organism of Disease iI
Staphylococci are frequently found in nature. They are present in the air, on
eating and drinking utensils, in nasal passages, boils, pimples, carbuncles and on •the skin and mucous membrane of food handlers. The organism may produce disease iprocesses e.g. localized abscesses, periostitis, septicemia, pyemia, urinary sepsis
or wound 'suppuration. Recentsurveys have shown that 50 per cent of normal adults
harbour the organism in the nasal passages and in i0 - 20 per cent of the populace, ithe microbes are present on the hands. Any skin abrasion, laceration or similar in-juries of the hands and fingers serve as ideal foci of infection.
n
Staphylococci are present in animals and poultry. Mastitis in cattle and goats Dis produced by this organism. Abscesses with septicemia may occur bothlin animals
and poultry. The organism is found on the skin, mucous membranes andin the nasal i
, passages of hogs and poultry, i
Recent problems of hospital-acquired infections in man have been sufficiently
serious to include them among communicable disease's of major public health import- iance. Many Of the human and animal strains of the organism are resistant to anti-biotics which further complicates the treatment of systemic infection.
Illness in humans produced by the organism occurs in two forms: i
i
i. Systemic - This results in the invasion of the Staphylococci into the blood stream ivia the skin or nasal passage. The organisms become lodged in the •
various organs of the body or in the circulatory or urinary systemi
producing abscesses and acute illness. Death may result.
2. Food Borne - This form of illness also produces systemic illness but in a dif- i
ferent manner. The organism must be permitted to seed the incriminated
food, grow and produce enterotoxin if conditions mre favourable. •Three factors are requied to produce food borne illness as follows: ii. Contamination _f food with coagulase positive enterotoxin producingstaphylococci.
2. A suitable food in which the organisms can grow. 3. Holding the i
food for a sufficient time at a temperature compatible for growth.i
Staphylococci cannot be excluded from our environment. Food borne infection •
due to this organism can only be controlled by the maintenance of established food |practices e.g.
i. Control and education of the food handler i
2. Refrigerator - below 45OF
|.3. Warm storage e.g. barbecued chicken or meats above 143°F
4. Heat-pasteurization 145°F for 30 minutes. •
H
!i06 i
I DR. N.A. Fish,Ontario Veterinary College;
i University of Guelph.
Regulatory Control of Animal Diseases of Public Health Importance
l In Canada, the regulatory control of infectious or contagious diseases of animals
is the responsibility of the Canada Department of Agriculture, Health of Animals Branch.
I The enforcement of this control may be shared by provincial authorities e.g. provin-cial departments of agriculture. In Ontario, the Veterinary Services Branch functions
as such a body. The federal government is also responsible for the control of themovement of animals from one province to another country. Likewise, the importation
I poultry products e.g. meat, wool, hides, as as straw,of animal and feathers well
fodder or other items used for feeding or caring for animals is rigidly controlled.This authority is exercised under the Animal Contagious Diseases Act and the Meat
I Inspection Act.
The predominant diseases which have public health importance and are under en-
I forcement are tuberculosis, anthrax, brucellosis, rabies and psittacosis. Of thesediseases, rabies may be considered as example of a contagious disease with the great-est public health significance, both at a local and national level. Rabies is
endemic in Ontario and p_opogated by wild animals, particularly the fox and skunk.
I Rabies virus is consistently found in the saliva of infected skunks. Racoons arelikely to be involved if the disease is found in a specific area.
I All rabies diagnosis in animals is conducted by the Heaith of Animals Branchlaboratories in Hull or Lethbridge. Brains are removed from suspect rabies cases by
H. of A. field veterinarians, carefully packaged and submitted to the laboratories.
i Reports are submitted to the local health department in the district of origin. Variouslivestock animals are readily infected with rabies including cattle, pigs, horses,
and sheep. Compensation is paid by the provincial and federal departments of agri-culture for farm animals that have died from rabies on 60 - 40 per cent basis. Free
I dog and cat vaccination clinics sponsored by the federal government are made avail-able in areas where rabies is endemic. About 96,000 dogs and cats were vaccinated
at these clinics in Ontario in 1967. During 1967, positive laboratory diagnosis on
l domestic and wild animals reached a total of 1411 for Canada in comparison to 1,241in 1966. Of this group, 1,066 positive cases were diagnosed from Ontario. This
represented 189 cattle, 800 foxes and skunks, and the remainder consisted of horses,
l raccoons, wolves, rodents and bats.
!
l 107
IDr. W.R. Mitchell,
Ontario Veterinary College, i
University of Guelph. I
MICROBES AND THEIR ENVIRONMENT Ill
Man lives, bathed in a sea of microbial activity. Microbes are man's best friends
and his worst enemies. Long before microbes were observed, their activity was used •to ferment and preserve food and at the same time the disease producers have caused 1great plagues throughout history. Microbiology is a relatively new science. Since
the development of the microscope, microbes are now observed, their growth and
behaviour patterns studied. They are now extensively classified. I
Many microbes are now identified with specific diseases in both animals and man
i.e. Brucella abortus - brucellosis; Leptospira pomona - leptospirosis; Mycobacterium •tuberculosis - tuberculosis, are well known microbes.
Changes in the environment of animals and humans is continuously providing new llopportunities for some microbes to survive or even thrive; for others the changes •lead to their destruction. i
In agriculture, we depend on the relationship of soils to crops to livestock Ito food_ In fact the intensification of husbandry methods provides us with an out-
standing example of the influence of environment on microbial population.
• !The broiler industry for example takes advantage of controlling environments so.that very large numbers of birds can be reared in a relatively small area. Duringthe past 20 years the amount of feed to produce a 3 1/2 lb. broiler has been reduced 1
from 14 lb. in 14 weeks to 9 ibs. in 9 weeks. One of the major reasons for this •
improved efficiency in production has been through the use of antibiotics to reduce
infections. Antibiotics are microbial products which are turned around to combat
pathogens. To Every action, there is a reaction. The microbes have reacted by •
establishing strains resistant to the antibiotics. Recently, the ability fo somebacteria to transmit the property of drug resistance from one species to another
has been demonstrated. In addition, the extensive use of drugs to control microbial •populations in food producing animals poses another problem. 1
Our world is full Of microbes and as we change our environment to escape oneform of life w_ may be creating a situation suitable to another kind. This situ- I
ation is illustrated by the change in the pattern of Salmonellosis in people. Thehuman types, Typhoid, para A and para B have been almost eliminated as causes Of
human disease, but with this decline has been a startling rise Of the number of •
cases of Salmonellosis due to speices of animal origin. m
As man's influence tochange his environment inCreases, so must his vigilance ll
with respect to unwanted effects of microbial activity. •
I
II
108 1
I DR. W.R. Mitchell,
Ontario Veterinary College,
I University of Guelph.
l RABIESRabies or hydrophobia, has been a scourge of mankind down through recorded
history. In 1804, Zinke demonstrated the virus in salvia. In 1880 Pas-Teur esta-
I passage of the virus in laboratory, which led toblished the method of serial the
his prophylactic treatment for exposed persons. He developed the terms "street"
virus, referring the natural occurring agent, and "fixed" virus referring to the
I virus after its incubation period had been fixed by serial passage. 40-50 passagesreduced its incubation period to six to seven days. Fixed virus loses its ability
to produce Negri bodies and its trophism for salivary gland tissue.
l The virus has been adapted to grow on chick, and duck embryo and tissue-culturemedia, an important step towards producing immunizing agents against rabies.
l Rabies is known to exist on all continents except_Australia. The principal car-riers are dogs and cats, and among wildlife forces, skunks, wolves, jackals, coyote,mongooses, weasels and bats.
l Changes in the relationship of man to his environment and his animals are re_
flected in changes in the epidemiology of rabies. The dog, due to its close assoc-
I iation with man, and its susceptibility to rabies, has long been the main source ofthe disease for humans, but wildlife is becoming a more important reservoir as dem-onstrated by the following tables.
I TABLE IRABIES IN
i WILDLIFE IN CANADA1966 - 1967 1965 - 1966
CANADA ONTARIO CANADA ONTARIO
l FOXES 519 453 428 389SKbXqKS 224 145 240 188
l MICE 3 - - -RATS i - - -
RACOONS 9 6 5 5
I WOLVES 5 5 3 2
BATS i0 7 12 8
I BADGERS i - - -GROUNDHOGS - - 1 1
l 772 616 689 593
FISCAL YEAR - APRIL TO MARCH
I FIGURES FROM NEWSLETTER - HEALTH OF ANIMALS BRANCH,CANADA DEPARTMENT OF AGRICULTURE
!I lO9
!i
TABLE II i
RABIES IN
DOMESTIC ANIMALS IN CANADA I
1966 - 1967 1965 - 1966
CANADA ONTARIO CANADA ONTARIO iDOGS 94 68 115 85
CATS 66 53 81 70 i
CATTLE 417 334 550 381
HORSES 15 13 21 18 I
SHEEP 52 50 65 32 ISWINE 32 25 39 30
GOATS - - 2 2 I
676 543 873 618
FISCAL YEAR - APRIL TO MARCH i
FIGURES FROM NEWSLETTER - HEALTH OF ANIMALS BRANCH ICANADA DEPARTMENT OF AGRICUETURE
iIIiIIi
ii0 i
I While the transmission of rabies is mainly a matter of spread by the bite ofan animal carrying the virus in its saliva, spread by aersol has also been demonstrated.
I Bats present a special problem in rabies control, especially in Central and SouthernAmerica. Some bats can apparently harbour the virus without suffering the disease.Some workers believe this maybe the means for the virus to live over winters.
I Animals appear to have varying degrees of susceptibility to the virus; fortun-ately, man is reasonably resistant.
l In Canada, the responsibility for the control of rabies is vested in the Healthof Animals Branch of the Federal Department of Agriculture, through the animal con-tagious diseases act. Laboratory diagnosis and field investigations are carried out
I by veterinarians in their employ.
The Statutes of Ontario provide authority for the Medical Officer of Health to
l enforce certain measures regarding rabies control.Diagnosis of Rabies
! •i. Biting animal should be confined and allowed to die, and thereby increase the
possibility of finding Negri bodies in smears or section of the hippocampus.
l 2. Fluorescent Antibody Test - Tissue specimens are placed in contact with conjugate(anti-rabies serum which has been "tagged" by the addition of a fluorescent dye)
and examined directly using UVL as a light source and a special system of filters
and condensers. This method is rapid and accurate when Conducted by competent
I persons.
When not found, mice inoculation tests are carried out using the intracere-
I bral route (i0 - 15% of cases not showing Negri bodies have proved to be positive bythis method). .03 ml of a 10-20% suspension into each of five mice per specimen.
Suspension is pooled sample of sections of hippocampus cerebellum and cerebral
l cortex. Salivary glands may also be tested as this is of great importance in esti-mating the risk to a human.
Control in Wildlife
l i. Reducing wildlife population by poison baits, trapping and shooting.
l 2. Artificially interrupting the breeding cycle using hormones.3. Vaccination.
l Control inDomestic Animals
i. Vaccination.
I 2. Control of stray dogs.
I 3. Education.
Local Treatment of Wounds
I The WHO Expert Committee recommends:
I. Thorough cleaning of site with soap or detergent.
!I iii
2. Apply concentrated nitric acid. I
3. Wound should not be sutured immediately. I
4. Antiserum should be infiltered into the base of the wound. Powdered gammarglobules
may be applied locally. ISummary
1. Immunization appears to be reducing the incidence of rabies in the canine species. I
2. Not all dogs with rabies excrete the virus in their saliva, but of those that do,
the period of excretion is usually three days prior to the onset of clinical Isymptoms.
3. Bats are important sources of rabies virus, and have been known to carry the rabies Ivirus in their saliva for several months.
4. Methods of immunization of persons and cattle against rabies still requires more
investigation. I
In man pre-exposure - Hamster kidney
post-exposure - serum and semple or duck embryo I
In cattle pre-exposure - HEP and Porcine kidney.
II
I DR. W.R. Mitchell,
Ontario Veterinary College,
I University of Guelph.
I MILK BORNE INFECTIONS
The Dairy Industry has undergone considerable change in recent years, not
i nly with respect to marketing, payment and distribution procedures, but also in thetechnology of milk harvesting, and processing.
In this latter connection, the changes at the farmlevel are improved milk-
I ng procedures and facilities for storing and handling milk. All Of these changeshave exerted an influence on milk "quality". The quality of milk may be defined in
a number of ways, but the tests used to measure raw milk quality in Ontario give a
I rough indication of the numbers of somatic cells, and microorganisms present;specifically the milk Gel Index test to measure cells and the Resazurin test to
measure biological activity.
I a good pipeline milking system, milk may be removed from the cow andWith
cooled to less than 50OF within a matter of minutes, and remains at approximately
38°F until pick-up time. Under these circumstances, the possibility of pathogens
I ncreasing significantly during storage is remote. However, conditions are suitableto the psychrophiles, especially since milk may not be delivered to the consumerfor four or more days after being removed from the cow.
I The time required for the present testing procedures, apart from the organ-o!eptic testing, does not permit the fieldman to receive a report about the quality
of raw milk until after it has been processed and consumed. The milk gel index test
I is used to screen out herds with "abnormal" milk. The number of cells in bulk tankmilk gives an indication of the amount of udder disease in a herd. Udder disease
is more a matter of economic loss to the producer than of concern about the health
I of the public.
The lack of agreement aboutthe best method to measure the number of somatic
i ells in raw milk is evident by the number of tests used. The indirect tests includethe Milk Gel Index, the "gel" test, the C.M.T., the Whiteside test, the Catalase
test, the Wisconsin test, the Michigan test, the Brabant test to name a few. All of
these tests depend upon the reaction of cellular DNA with a non ionic surface acti-
I vating to produce a thickening or gelling affect.agent
Milk is no longer a source of human infection as handled according to regu-
I lations. But during the period 1906-1933, 48 epidemics of milk-borne disease out-breaks were reported involving some 1712 cases and 681 deaths. These figures only
include typhoid, paratyphoid, scarlet fever and septic sore throat.
I When pasteurization became a mandatory procedure in 1938 milk, the poten-tial of milk as a source of human disease was virtually eliminated. There will
probably always be instances of post pasteurization contamination, some of which
I will lead to milk spoilage and some to disease in animals or humans.
The Sanitarian's responsibility has now shifted from the farm to the dis-
I tributor and the consumer. While certain microorganisms and in particular Staphy-lococci will continue to be sources of human disease, indirect contamination of milk
with chemical and radio active substances may prove to be of much greater importance
i than biological contamination.
I 113
IDR. W.R. Mitchell,
Ontario Veterinary College,
University of Guelph. •
A KEY TO FOOD POISONING AND FOOD INFECTION •AND AN OUTLINE PROCEDURE FOR THE INVESTIGATION OF A FOOD-BORNE OUTBREAK |
Investisation of a Food-Borne Outbreak i
i. Determine as quickly as possible from the information readily available theanswers to the questions Who? What? When? and Where? Call several local phy-sicians and ask for an estimate Of the number of cases and for information i
about symptoms. Ask for permission to query the Doctor's patients.
2. Make a provisional plan to guide you in assembling information. Ask that foods •be saved under refrigeration and whenever possible put them immediately in Ideep-freeze in the original containers or vessels properly covered, or in sterile
containers. If stool specimens are in order, make the necessary arrangements. iSince foods are involved, the first need is for a correct list of the foods •
served for several meals back and a record of the groups or persons concernedi
Do not jump to conclusions as to cause no matter how obvious the situation appears.
It is important to remember that the people in the affected group who did not
eat or who were not ill are just as useful as the patients in the investigationof an outbreak.
Tabulate data as you go by keeping notes on a prepared sheet. If this is done i3.
with reasonable accuracy, a useful estimate of the attack rate may be made and
further tabulations can be set up later to allow more detailed s_udy, ii
Meals and/or _I i
Name, Address Ate Did not eat Food eaten I Remarks I
Ill* Not Ill Ill* Not Ill i lH
_ i |* Write in hour of onset on ill persons.
4. By using the hour of onset of the first case as a starting point, one can de- i
termine the time distribution of hours, or dates, of onset (the epidemic curve).i
In food peisoning this is essential information. It is not uncommon to discover
that the history of one or two persons in the group will reveal the approximate time i
of exposure and indicate the probable incubation period for the entire group. The
median average, (the middle value in any series arranged in order of size) is a very
useful average in public health since computing it does not require addition and •
division. Also Unlike the arithmetic mean average, the median is not affected by |extremely small or extremely large values in the series. It is therefore particular-ly useful in attempting to determine the average hour of onset and the average incu- Rbation period of an epidemic illness. •
i
I 5. Make a rough spot map to indicate distribution of cases.
I 6. Classify the persons involved as to age, sex, colour andwith regard to any othercharacteristics that may seem important.
7. (a) From the rough data, it is easily possible to make a table which will show
l an accurate attack rate for all the foods served.PART A
I. (a) Disease characterized by definite and consistant pattern of symptoms in
E several persons ---Single etiologic agent - I(b) Disease not characterized by a consistent pattern of symptoms in several
i persons -Multiple agents (consider each type of case separately). IIll.(a) Incidence Of one disease pattern significantly greater than normally expected
during a particular season, or in area, or in category of persons being
l checked --Disease outbreak - III
(b) Incidence of specific disease not materially greater than expected when
l measured by the customary means employed for determining presence of diseaseAttention phenomenon.
III. (a) Disease outbreak tending to be explosive, or cases coming in bursts, occurring
l a group related by_ a common experience by same experiencein definite (or the
at different times) Common source outbreak B
l (b) Disease incidence building up gradually and occurring without identifiablerelationship to a common experience ...... Person to person spread B
l PART BI. (a) Fever absent or very slight- Poisonings II
l (b) Fever usually present .... Infections (and allergic reactions) V
II. (a) Median incubation period very short (range 5 minutes - 2 hours), onset
l frequently within minutes after ingestion of food and almost always withintwo hours, nausea, vomiting, diarrhea, abdominal cramps, etc., accompanied
by symptoms referable to the nervous system such as tingling sensations,muscle weakness or muscle spasm, paralysis, localized anaesthesia, mental
l confusion, etc.Chemical poisoning
Shellfish poisoning
l Plant poisoning
(b) Median incubation period longer than in (a), usually at least two hours
l although individual onsets may occur earlier - IIIIII. (a) Median incubation period about two hours (range 30 minutes to 4 hours), onset
abrupt, severe nausea, vomiting and prostration, often severe diarrhea, fever
I may occur but sub-normal temperatures are morefrequent, entire outbreak
explosive or cases occurring in bursts. No direct involvement of nervous
system.
l Staphylococcic food poisoning
(b) Median incubation period four hours or longer IV
!l 115
iIV. (a) Median incubation period four to twelve hours (range 6-15 hours), nausea, i
retching, vomiting, salivation, excessive perspiration, a flow of tears,
pain in abdomen and violent movement of intestine which causes profuse Rwater evacuation.
Mushroom poisoning i(b) Median incubation period 18 hours or more, headache, weakness, constipation
or lack of gastrointestinal symptoms, double vision, difficulty of swallow-
ing, difficulty of speech, i
Botulism
Food Infection I
V. (a) Onset frequently dramatic, median incubation period less than six hours •(usually 1-2 hours), fever, blood in urine (5-40 hours) |
Allergic reaction to fava beans
(b) Median incubation period more than six hours - VI
VI. (a) Illness mild, recovery rapid and fever usually absent. Outbreak charac- •terized by nausea, colicky pains and diarrhea, sometimes vomiting, median
incubation period about 12 hours (range 2-18 hours), recovery within24 hours.
Streptococcic food infection or Clostridium •
perfringens (welchii) food infectioni
(b) Illness more severe and of longer duration than 24 hours - VII i
VII. (a) Median incubation period about 18 hours (range 6-48 hours), acute di- •arrhea, fever, nausea and vomiting are usually present, chills, headache, icramping and abdominal pains commonly occur. Salmonella infection.
(b) Median incubation period more than 18 hours - VIII I
VIII. (a) Acute onset, diarrhea , fever, tenesmus and frequent defecation, incuba-
tion period usually about four days. Outbreak tends to be sharply defined •only if common source is involved.
Bacillary Dysentery
(Shigellosis) i
(b) Onset not abrupt, continued fever and increasing symptoms of severe sys-
temic infection, some diarrheal disturbance but this is usually not a very imarked symptom, rose spots on trunk.
Typhoid i
m
Total Who Ate Not Iii Iii Attack Rate
# # # %
I ChickenMashed Potatoes
Green Peas
I Pear SaladGravy ,"Rolls
l ButterStrawberry ChiffonPie
Coffee
TeaMilk
!Frequently, however, these preliminary data indicate that it would be worthwhile to
send out a complete questionnaire. Such a questionnaire, properly handled, can
l produce in a few hours information that the most industrious shoe-leather epidemio-logist would take weeks to assemble.
l (b) If the total group affected, i.e. the "Universe", numbers 30 or more, a muchmore useful tabulation is the fou[-fold table from which can be computed anattack rate for both those who ate and those who did not eat a given food, or
l who did or did not do a particular thing.
I Iii Not Iii TOTAL
Ate
| ,,Did not eat
!Total
!However, the greatest value of this tabualtion is that one can figure the probabilitythat such a distribution would occur by chance alone, i.e., apply the Chi-square test
l for statistical significance. With good data tabulated in this form it would bepossible to telephone in the information to Epidemiology and get back an answer on
the probabilities within an hour or two.
l 8. The c_ief pitfall is the "Universe" problem. Only those persons who were partsof the group being studied and who had a chance to do, or not to do, the thing
at issue can be included in a particular probability determination. In a series
I on a group may vary considerably. Forof calculations school the "Universe"
example, it would be erroneous to include absent students in an ate vs d_d not
eat table. On the other hand, these students become the most important part
l of the "Universe" if the tabulation is on presence vs absence. Again the absentstudents would be omitted if one were computing the probability on rode the
school bus vs did not ride the bus, since they not only did not ride the bus
while absent but were not exposed to whatever other influences obtained in sch9o_
i on that day.
l 117
i9. A report should be prepared on every outbreak and copies forwarded to the I
officials concerned.
EPIDEMIOLOGYPROBLEM
An Outbreak of Gastroenteritis •
On Saturday, May 22, a group of ll men met at summer camp °for a planning session
prior to opening of the camp. The wives of four of the men accompanied the group
to serve lunch and supper and to spend their leisure time playing bridge. They iarrived at the camp about i0:00 a.m. and left immediately after supper. i
The lunch consisted of bread, butter, cold turkey, potato salad, milk, and jello •and was served at 12:30. The supper included fruit cocktail, baked ham, cold aspar-
agus, bread, coffee, and ice cream and was served promptly at 6:00 p.m. All foods
except the coffee were prepared or purchased on the day before by the wives and car-ried to the camp mess facilities. i
That evening, 8 of the 15 who spent the day together and shared the common foods
became ill. All were recovered within 48 hours. Data on each person is attached, iUsing these materials work up the following:
i. Using the Symptom Tally Work Sheet, determine the most commonly cccuring •symptoms. iOn the basis of this tabulation prepare a list of food borne diseases which
fit these symptoms, ii
2. Prepare on the Epidemic Curve Tally Sheet a tally of the time of onset.i
Prepare a graph to illustrate the epidemic curve. B
3. Using the Attack Rate Work Sheet, calculate the attack rates for each ifood served. iWhat is the suspected food?
4. Prepare on the Incubation Curve Tally Sheet a tabulation of the possible iincubation times.
i
On a basis of this additional evidence, what disease is it more likely ito be?
5. Prepare a short narrative describing your hypothesis and the effect that Ritems i through 4 had on it.
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118 i
mINTERVIEWS WITH PERSONS ILL & WELL
m
Lunch Supper Onset Symptoms
No. 1 Cold Turkey Baked Ham 7:30 p.m. Abd° CrampsPotato Salad Bread Diarrhea
M-23 Milk CoffeeIce Cream
No. 2 Bread Fruit Cocktail Not IiiButter Baked Ham
M-46 Potato Salad BreadMilk Ice Cream
No. 3 Bread Fruit Cocktail 8:00 p.m. DiarrheaButter Baked Ham Vomiting
M-22 Cold Turkey Cold Asparagus HeadachePotato Salad Bread Abd. CrampsMilk
Jello
I No. 4 Cold Turkey Fruit Cocktail Not IiiMilk ColdAsparagus
I F-37 Jello CoffeeNo. 5 JCold Turkey Fruit Cocktail 10:30 p.m. Diarrhea
Potato Salad Baked Ham
F-29 Milk Cold AsparagusCoffee
Ice Cream
I No. 6 Bread Fruit Cocktail Not IllPotato Salad Baked Ham
m M-52 Jello CoffeeIce Cream
Bread
m No. 7 Bread Fruit Cocktail 8:30 P.M. VomitingButter Baked Ham Diarrhea
M-32 Cold Turkey Cold Asparagus
m Potato Salad CoffeeMilk Ice Cream
Jello
m No. 8 Cold Turkey Baked Ham Not IiiMilk Cold Asparagus
F-31 Bread
m coffeeIce Cream
m No. 9 Bread Fruit Cocktail i0:00 p.m. DiarrheaButter Bread Abd. Cramps
M-40 Cold Turkey CoffeePotato Salad Ice Cream
m MilkJello
m 119
lINTERVIEWS WITH PERSONS ILL & WELL •
Lunch Supper Onset Symptoms l
No. i0 Bread Fruit Cocktail Not Iii
Butter Baked Ham •
IM-30 Potato Salad BreadMilk Ice Cream
Jello|
No. ii Cold Turkey Fruit Cocktail 9:15 p.m. Diarrhea IMilk Baked Ham
F-28 Jello Cold Asparagus 1Ice Cream i
No. 12 Bread Fruit Cocktail Not IIi •Butter Baked Ham
M-38 Potato Salad Cold AsparagusMilk Coffee
I
Jello Ice Cream l
No. 13 Bread Fruit Cocktail 8:30 p.m. Diarrhea
Butter Baked Ham Abd. Cramps I
M-40 Milk Cold Asparagus Bloody Stools iJello Coffee
Ice Cream iNo. 14 Bread Fruit Cocktail Not Iii l
Butter Cold Asparagus
M-35 Milk Coffee 1iJello
No. 15 Bread Baked Ham 12:30 a.m. Diarrhea •Butter Bread
M-42 Cold Turkey CoffeePotato Salad Ice Cream
Milk l
i. Symptoms Tallyl
SYMPTOM TALLY NUMBER 1
Abdominal Cramps l
Diarrhea
Vomiting l
Headache l
Bloody Stool
Fever l
Total l
120 , I
I 2. EPIDEMIC CURVE TALLY
I TIME OF ONSET TALLY OF ONSETS NUMBER
I 7:00- 7:598:00- 8:59
I 9:00- 9:59
i0:00- 10:59
I ii:00" 11:59
I 12:00 - 12:59
TOTAL
| '3. ATTACK RATE WORK SHEET
I EPIDEMIOLOGY & CONTROL OF DISEASESFOOD-BORNE
Outbreak Problem
!FOOD PERSONS EATING FOOD ITEM PERSONS NOT EATING FOOD ITEM
I Total Iii Well !Attack Total Iii Well AttackRate Rate
I Lunch:
Bread
I Butter
I Cold Turkey
Potato Salad
IMilk
I Jello
I 121
!CONTINUED
PERSONS EATING FOOD ITEM PERSONS NOT EATING FOODITEM IFOODI
Total Iii Well Attack Total Ill Well Attack
Rate Rate
Supper: I
Fruit Cocktail IBaked Ham
Cold Asparagus I
Bread
Coffee R
Ice Cream l
4. INCUBATION CURVE TALLY I
!Time of Onset Incubation Time
(Earliest to Latest) in Hours I
i.
3 !4.
6.
7. L m
8 !MEDIAN INCUBATION TIME I
IONTARIO VETERINARY COLLEGE
I The following films are available from:Department of Health, Education & Welfare,Public HealthServices,
I ational Medical Audiovisual Centre (Annex)CHAMBLEE, Georgia, 30005, U.S.A.
i i. Mississippi Valley Disease2. Epidemiology of Brucellosis3. Epidemiology of Salmonellosis in Man and Animals4. Leptospirosis
I 5. Public Health Aspects of Poultry Processing.
The following films are available from: Canadian Film Institute,
I 762 Carling Avenue,Ottawa, Ontario
Ii Syphilitic Veneral Disease
I . Causter Testing3. Leptospirosis4. Outbreak of Salmonella Infection.
I V.D. See Your Doctor - Moreland Latchford Productions Limited,2298 Yonge Street,
I (RESTRICTED) Toronto 12, OntarioThe following films are available from: Audio Visual Services,
University of Guelph,
I Guelph, Ontario(Miss) Mary FazzariFilm Libra±ian.
I I. Enemy Bacteria2. Bacteria Laboratory Study
I . Micro-Organisms - Beneficial Activities4. Micro-Organisms - Harmful Activities5. Foot. & Mouth Disease .- Saskatchewan (There is also a copy filmed in
Mexico)
I 6. Triple Threat Brucellosis7. Leptospirosis8. Rabies, Dog, Cat, Cattle
I 9. Rabies - Humani0. Rabies - Clinical Cases.(A few of the above films are available from:
i Canadian Film Institute.Hospital Sepsis - available from De Laval Company Limited,113 Park Street, Peterborough,Ontario.
I Att. Mr. A. G. Kerr.
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