TestingNew Wellsfor Coliform Bacteria

HELPING ENSURE DRINKING WATER SAFETY

EnsureSafety of DrinkingWater

MaintainConsumer

Confidencein

Groundwater

Why Test Well Water for Coliform Bacteria?

Waterborne Pathogen Exposure Routes

INGESTION

FOOD

DERMAL CONTACT

AEROSOLINHALATION

What are Coliform Bacteria?

AEROBIC AND FACULTATIVE ANAEROBIC GRAM-NEGATIVE NONSPORE-FORMING ROD-SHAPED

FERMENTS LACTOSE WITH GAS PRODUCTION WITHIN 48 HOURS @ 35 DEGREES CELSIUS

MEMBRANE FILTER ANALYSIS

Coliform Bacteria are Indicator Organisms

Positive coliform test indicates potential presence of pathogenic (disease-causing) microbes

Testing for pathogens requires large volumes of water andcomplex lab procedures

Coliforms are found in greater numbers than pathogens

E.coli bacteria live longer than fecal coliforms

Coliform testing is easier, more economical and safer than pathogen testing.

TOTAL COLIFORMS

FECAL COLIFORMS

E. COLI

PATHOGENIC E. COLI

Sources of Coliform Bacteria

INTESTINESOF

WARM-BLOODEDANIMALS

SURFACEWATER

&FLOODWATER

ON-SITE SEWAGESYSTEMS &SEWERLINE

LEAKS

AGRICULTURALWASTE RUNOFF

SOIL&

VEGETATION

GROUNDWATER

Etiologies of Waterborne Illness Outbreaks(1991 – 2002)

ACUTEGASTROINTESTINALILLNESS (AGI), UNIDENTIFIED 38%

CHEMICALPOISONING 16%

GIARDIASIS 12%

CRYPTOSPORIDIOSIS 7%

AGI – NOROVIRUS 6%

AGI – E. COLI 0157:H7 5%

SHIGELLOSIS 4%

OTHERDISEASES 6%

CAMPYLOBACTERIOSIS 3%

LEGIONELLA 3%

Burden of Illness Pyramid

(From: Journal of Water and Health, Estimating Disease Risks Associated With Drinking Water Microbial Exposures, Vol. 4, Supplement 2, 2006)

Person is exposed to pathogen in water and becomes infected

Persons who exhibit symptoms

Persons who visit physician or health care facility

Persons who are hospitalized

Deaths

WATERBORNEPATHOGENS

E. coli

Cryptosporidium

SymptomaticHost

ACUTE GASTROENTERITIS SYMPTOMS:

STOMACHCRAMPS

DIARRHEA

VOMITING FEVER

NAUSEA

E. coli

Cryptosporidium

WATERBORNEPATHOGENS

AsymptomaticHost Secondary

Host

FECALTO ORAL

TRANSFEROF

PATHOGEN

MICHIGAN GROUNDWATERIS GENERALLY FREE OF:

• COLIFORM BACTERIA• DISEASE-CAUSING MICROBES

Exceptions: Shallow carbonate bedrock (Karst)

Very shallow coarse sand & gravel

Faulty well construction

Unplugged abandonedwells

Unsealed, Abandoned Well Causes Bacteria Problemsfor Noncommunity Public Water-Supply Well

Reported by Minnesota Dept. of Health, Minnesota Well Management News Fall 2006 / Winter 2007, Volume 26, No. 2

PERSISTENT COLIFORMS IN NCPWS (>2 YRS.)(24 YR. OLD WELL - 57 FT. DEEP - 4 IN. CASING)

REPEAT WELL DISINFECTIONS UNSUCCESSFUL

INVESTIGATION OF FACILITY HISTORY FOLLOWED BYMETAL DETECTOR SEARCH BY MDH - ABANDONED WELLWITHIN 10 FT. OF ACTIVE WELL IS SUSPECTED

EXCAVATION FINDS OLD WELL UNCAPPED 7 FT. BELOW GRADE,10 FT FROM ACTIVE WELL - UNSEALED – SAND & DEBRIS FROM 35 FT. TO BOTTOM OF 60 FT. WELL

STATIC WATER LEVEL SAME AS ACTIVE WELL – HYDRAULICCONNECTION BETWEEN WELLS

AFTER OLD WELL PROPERLY PLUGGED – CONSISTENTNEGATIVE COLIFORM BACTERIA SAMPLES

Potential Sources of Microbial Contamination

from Well Drilling Practices

OBTAINING DRILLING WATERFROM SURFACE WATERSOURCE

USING BIODEGRADABLEDRILLING FLUID OR LOST CIRCULATION ADDITIVES

IRON BACTERIAIN SURFACEWATER

Introducing Contaminants DuringWell Construction

FAILURE TO MAINTAINMINIMUM 10 PPMCHLORINE RESIDUALIN DRILLING WATER

TRANSFERRING CONTAMINANTS FROM GROUND SURFACE INTO WELL BOREHOLE ENCOURAGE DRILLERS

TO USE TEST STRIPS

DOWNWARD LEAKAGE AROUND UNGROUTED CASING

UNCONFINED AQUIFER

STATIC WATER LEVEL

DOWNWARD LEAKAGE

CONTAMINANT PLUME

UNSEALED ANNULARSPACE AROUND

CASING

INFILTRATION OF SURFACE CONTAMINANTS

UNSEALEDANNULUS BETWEENCASING &BOREHOLE

GROUTPIPE

DIRECT PATHWAY TO AQUIFERIF LEFTUNGROUTEDOR IMPROPERLYGROUTED

Would this temporary cap keep contaminantsout of the well?

Sanitary & Preventive PracticesDuring Well Completion

KEEP WELL COMPONENTSELEVATED OFF GROUND…..USE SANITARY HANDLINGPRACTICES

CLEANDRILLING TOOLS

BETWEEN WELLS TO PREVENT

CROSS-CONTAMINATION

COMPONENTSOF A

SAFE & RELIABLE WATER WELL

PROPERWELL

CONSTRUCTIONMATERIALS

SANITARYWELL

COMPLETIONPRACTICES

TRAINEDPROFESSIONALWATER WELL

CONTRACTORS

PROPER WATER SYSTEM

MAINTENANCE

ROUTINEMONITORING

OFWATER

QUALITY

TARGETAQUIFER HASAMPLE YIELD

&SAFE WATER

SUFFICIENTSEPARATION

FROMCONTAMINATION

SOURCES

WELLS MOST VUNERABLE

TO MICROBIALCONTAMINATION

POOR CONSTRUCTION(UNSEALED ANNULUS

OR DUG WELL)

DEFICIENT WELL HEAD(CRACKED WELL CAP

OR OPEN VENT)

SHALLOW DEPTH(OR SHORT CASING

IN BEDROCK)

FLOODING,BURIED WELL HEAD

OR SUBMERGEDIN WELL PIT

SEWER LINE BREAK,SEWAGE OVERFLOW

OR CROSS-CONNECTION

TOO CLOSE TO SEPTIC SYSTEM,

AGRIC. RUNOFF ORABANDONED WELL

OLD WELLS WITH CORRODED

WELL CASING

LHD Water Sampling Activities

COLLECT BACTI SAMPLES OR PROVIDE SAMPLE BOTTLES

TO WELL DRILLER OR OWNER

TRACK TEST RESULTS TOENSURE ALL NEW

WELLS ARE TESTED

WITHHOLD ISSUANCE OF WELL APPROVAL UNTIL

SAFE BACTERIOLOGICALSAMPLES ARE

ATTAINED

USE WELL PERMIT PROGRAMTO NOTIFY WELL OWNER

OF NEED TOCOLLECT SAMPLE

PROMPT FOLLOW-UP ON POSITIVE COLIFORM

RESULTS, ESPECIALLYE. COLI POSITIVES

Why Should Well Contractors CollectBacteriological Water Samples?

• Reduce public health risk

• Enhance industry professionalism

• Validate quality of contractors’ work

• Reduce contractor liability

Why Should Well Contractors Collect Bacteriological Water Samples?

• Improve customer confidence in groundwater

• Reduce customer anxiety over positive test results

• Gain better understanding of public health within water well industry

Why Should Well Contractors CollectBacteriological Water Samples?

• Current practice leaves customers with sense of purchasing incomplete product

• Contractor knows when water system is complete and ready for sampling.

• Well owners are unfamiliar with sampling protocol – prone to false positives.

Why Should Well Contractors CollectBacteriological Water Samples?

• Contractor ownership of sampling protocol• Fewer disputes over sampling location and

technique• Reduction of complaints over validity of

sample results• Encourages more sanitary

drilling practices

WORK WITH LOCAL BUILDING CODE OFFICIAL

WATERSUPPLY

APPROVALBY LHD

BUILDINGINSPECTOR

CERTIFICATEOF

OCCUPANCY