` area iv: pollution iva3: water pollution. ` 20-1 types, effects, sources of water pollution l...

Area IV: Pollution

IVA3: Water Pollution

20-1 Types, Effects, Sources of Water Pollution

water is polluted by infectious bacteria, inorganic and organic chemicals, and excess heat

water pollution: any chemical, biological, or physical change in water quality that has a harmful effect on living organisms

the WHO estimates that 3.4 million people/yr people die prematurely from waterborne diseases

an estimated 1.5 million people/yr in U.S. become ill from infectious agents


scientists monitor water quality by using bacterial counts, chemical analysis, and indicator organisms

number of colonies of fecal coliform bacteria present in a water sample

drinking water: 0 colonies/100 mL swimming water: < 200 colonies/100 mL

bacterial source tracking (BST) biological oxygen demand (BOD): the

amount of dissolved oxygen consumed by aquatic decomposers

Fig. 20-2 Fecal coliform bacteria

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In May 2000 the small community of Walkerton, Ontario was laid waste by a toxic strain of E. coli:0157.

The contamination came from the public water supply.

Six people died in the first week including a two year old daughter of a local medical doctor.

Four new cases surfaced in late July, all very young children.

Over a thousand innocent people were infected.

bss.sfsu.edu/ehines/geog600/ Freshwater%20and%20ocean%20Pollution.ppt

` Waterborne Bacteria

Escherichia coli Vibrio sp.Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio

Disease symptoms usually are explosive emissions from either end of the digestive tract

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Indicator Tests

Total coliform[Endo agar]

Fecal coliform[m-FC agar]

Fecal streptococci[M-enterococcus]

Prescott et al., MicrobiologyBarbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio


scientists monitor water quality, cont. chemical analysis: inorganic and organic

chemicals present, sediment content, and turbidity of water

indicator species genetic techniques are being used to develop

organisms that will glow in the presence of specific pollutants such as toxic heavy metals in the ocean and carcinogens in food

Fig. 20-3 Water quality and dissolved oxygen


water pollution can come from a single source or variety of dispersed sources

point sources discharge at specific locations examples: drainpipes, sewer lines easy to identify, monitor, and regulate

non-point sources are scattered and diffuse and can’t be traced to any single site of discharge

examples: runoff from croplands, livestock feedlots

difficult and expensive to identify and control these discharges

Fig. 20-4 Point and nonpoint sources


sources of water pollution, cont. leading sources: agriculture, industries, mining

agricultural activities: erosion overgrazing fertilizers pesticides excess salt from irrigated soils


too much rain and too little rain can increase water pollution

increased moisture with more intense rains can flush harmful chemicals, plant nutrients, and microorganisms into waterways

prolonged drought can reduce river flows so there is less dilution available

warmer water contains less dissolved oxygen

`Causes of

Acid Rain

Sulfur dioxide (SO2) and nitrogen oxides (NOx) are the

primary causes of acid rain.

In the US, about 2/3 of all SO2 and 1/4 of all NOx comes

from electric power generation that relies on burning

fossil fuels like coal.

`Buffering Capacity

Acid rain primarily affects sensitive bodies of water, which are located in watersheds whose soils have a limited “buffering capacity”Lakes and streams become acidic when the water itself and its surrounding soil cannot buffer the acid rain enough to neutralize itSome lakes now have a pH value of less than 5

`Effects on Wildlife

Generally, the young of most species are more sensitive to environmental conditions than adultsAt pH 5, most fish eggs cannot hatchAt lower pH levels, some adult fish dieSome acid lakes

have no fish

20-2 Pollution of Freshwater Streams streams can recover from moderate levels

of degradable water pollutants if the flows are not reduced

dilution and biodegradation can allow recovery of stream pollution if:

they are not overloaded do not have reduced flow due to damming,

agricultural diversion, or drought

20-2 Pollution of Freshwater Streams stream recovery, cont.

breakdown of pollutants by bacteria creates an oxygen sag curve

organisms with a high oxygen demand can’t survive in the curve

factors in size of curve: volume of the stream volume of wastes entering flow rate temperature pH levels

Fig. 20-5 Dilution and decay of wastes

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yeast

Color Indicator

Distilled water

Pollutant (milk)

Investigating BOD Amount of dissolved oxygen needed by aerobic decomposers to break down the organic materials in a given volume of water at a certain temperature over a specified time period

`Investigating BOD Amount of dissolved oxygen needed by aerobic decomposers to break down the organic materials in a given volume of water at a certain temperature

Test Tube B contains 10ml milk, yeast and methylene Blue

Test Tube A the control contains distilled water, yeast and methylene Blue

Initial Demonstration Both started Dark Blue-

Picture taken after 10 min at 28deg Celcius-(84 F)

`Initial Demonstration Both started Dark Blue-

Picture taken after 20 min at 28deg Celcius-(84 F)

`

8AM

Initial setup with series of dilutions containing degrees of pollutants

Level of O2 high-indicated by blue color

(BOD)Control 1/16 1/8 ¼ ½ full concentration

`After about 1 hr the tubes began to change color.

Why are those to the left darker?

(BOD) Control 1/16 1/8 ¼ ½ full concentrationm

milk

`

Ultimate results BOD level obvious G

Greater the BOD stronger the reattion…

More white… the more oxygen present

(BOD) Control 1/16 1/8 ¼ ½ full concentration

milk

20-2 Pollution of Freshwater Streams most developed countries have reduced

point source pollution, but toxic chemicals and pollution from non-point sources are still problems

the U.S. has avoided increases in pollution from point sources in most streams

cleanup of rivers: Cuyahoga River in Ohio and the Thames River in Great Britain

there are sometimes large fish kills, and contamination of drinking water from industry, mining, and non-point runoff of fertilizers and pesticides

20-2 Pollution of Freshwater Streams stream pollution in most developing

countries is a serious and growing problem half of the world’s 500 major rivers are heavily

polluted many run through developing countries where

waste treatment is minimal or nonexistent

20-2 Pollution of Freshwater Streams the Ganges River in India is severally

polluted ~350 million people live in the Ganges River

basin with little treatment of sewage Hindu beliefs compound problem

air pollution from cremated bodies water pollution from bodies thrown in river

government solutions: waste treatment plants in the 29 large cities

along the Ganges electric crematoriums on its banks introduction of snapping turtles as body

scavengers

20-3 Pollution of Freshwater Lakes lakes are less effective at diluting pollutants

that enter them often stratified with little vertical mixing very little flow occurring may take from 1–100 years to flush and

change water in lakes and reservoirs much more vulnerable to runoff contamination

of all kinds of materials chemical concentrations build up as they pass

through the food webs in lakes

Fig. 20-6 Biomagnification of PCBs

20-3 Pollution of Freshwater Lakes human activities can reduce dissolved

oxygen and kill some aquatic species natural eutrophication: nutrient enrichment of

lakes from runoff depends on composition of the surrounding

drainage basin can enrich abundance of desirable

organisms cultural eutrophication occurs due to runoff

usually near urban or agricultural areas and in coastal water, enclosed estuaries, and bays

can lead to serious pollution problems

Oligotrophic lake

Eutrophic lake

Fig. 20-7 Cultural eutrophication

20-3 Pollution of Freshwater Lakes human activities, cont.

cultural eutrophication, cont. the EPA states that 85% of large lakes near

major population centers in U.S. have some amount of cultural eutrophication

can be reduced or prevented by: banning or limiting phosphates in

detergents advanced treatment methods to remove

nitrates and phosphates from wastewater use of soil conservation to reduce runoff

20-3 Pollution of Freshwater Lakes human activities, cont.

hot weather or drought -> “blooms” of organisms -> reduction in lake productivity

reduced sunlight + decomposition -> increase in bacteria populations -> decrease in DO -> fish kills -> anaerobic bacteria take over

cleanup of lakes includes removing excess weeds, controlling plant growth, and pumping air through lakes and reservoirs to avoid oxygen depletion

pollution prevention is cheaper than cleanup

20-3 Pollution of Freshwater Lakes Case Study in lake recovery: Lake

Washington, Seattle sewage diverted from the lake to Puget Sound,

where rapid water exchange dilutes sewage recovery took 4 years lake had not filled with weeds and sediment concern about Puget Sound due to increased

urban runoff and growing population What is the best way to deal with pollution?

Lake Washington

20-3 Pollution of Freshwater Lakes Case Study: pollution of the Great Lakes

has dropped but is still a problem the Great Lakes contain about 95% of the

fresh surface water in the United States, and 20% of the world’s fresh surface water

> 38 million people obtain drinking water from the lakes

vulnerable due to less than 1% outflow to the St. Lawrence River but lots of inputs

Lake Erie: shallowest; was the most polluted; high concentration of people and industry

Fig. 20-8 Great Lakes basin

Western Lake Eerie

20-3 Pollution of Freshwater Lakes Case Study: Great Lakes pollution, cont.

since 1972, the U.S. and Canada have worked together to reduce pollution

there is still a large area of depleted oxygen that occurs in the center of the lake each August for unknown reasons

a 2000 survey by the EPA stated that more than ¾ of the shoreline is not clean enough for swimming or use as drinking water

non-point land runoff is now a greater problem than industrial pollution

20-3 Pollution of Freshwater Lakes Case Study: Great Lakes pollution, cont.

biomagnification of the depositions from atmospheric contaminants means that one fish in four is unsafe for human consumption

EPA funding for cleanup has also dropped by 80% since 1992

environmentalists call for banning the use of bleach, building new incinerators, and stopping the discharge into the lakes of 70 toxic chemicals

20-4 Pollution of Groundwater groundwater is vulnerable to pollution

spilling gasoline, oil, paint thinners, etc. onto the ground can contaminate groundwater

low-risk ecological problem high-risk health problem contaminated water in the aquifer will slowly

flow, creating a plume of contaminated water contaminants in groundwater are not diluted or

dispersed because this water moves usually less than 0.3 meter per day

20-4 Pollution of Groundwater groundwater vulnerability, cont.

cleansing is slow; factors: lower oxygen content colder temperature of the water smaller populations of decomposing

bacteria it can take hundreds of years to cleanse

degradable wastes; nondegradable wastes are there permanently

20-4 Pollution of Groundwater the extent of groundwater contamination is

generally unknown EPA and U.S. Geological Survey figures state

that one or more organic chemicals contaminate about 45% of municipal groundwater supplies in the U.S.

~26,000 industrial waste ponds and lagoons in U.S. do not have a liner to prevent seepage

many underground storage tanks have leaks determining the extent of a leak is costly, and

the cost of cleanup is more costly yet

Fig. 20-9 Groundwater contamination

20-4 Pollution of Groundwater groundwater contamination, cont.

nitrates can contaminate groundwater, esp. in agricultural areas; form nitrites in the body

arsenic is released into drinking water when a well is drilled into arsenic-rich soils and rock

WHO estimates that more than 112 million people drink water containing 5–100 times the recommended level of 10 parts/billion

Bangladesh has a serious problem with arsenic, but the UN and several NGOs have begun to assess wells and tag them

20-4 Pollution of Groundwater prevention is the most effective and

affordable way to protect groundwater from pollutants

underground tanks in the U.S. and some other developed countries are now strictly regulated

old, leaky tanks are being removed, and the surrounding soils are being treated

Fig. 20-10 Groundwater pollution

20-6 Preventing Surface Water Pollution reduce non-point pollution by preventing it

from reaching bodies of surface water agricultural non-point pollution can be reduced

by: reducing soil erosion reducing fertilizer use; slow-release fertilizer reforestation of watersheds keeping cover crops on farmland planting buffer zones between farmland and

surface water nearby relying more on bio controls than pesticides

EPA required to require 15,500 of the largest feedlots to apply for EPA permits

20-6 Preventing Surface Water Pollution most developing countries do not have

laws to set water pollution standards most cities in developing countries discharge

80–90% of untreated sewage water used for drinking, bathing, and washing clothes

in U.S., the Clean Water Act sets standards for allowed levels of key water pollutants and requires polluters to obtain permits to discharge pollutants into aquatic systems

EPA is experimenting with a discharge trading policy using credits

20-6 Preventing Surface Water Pollution septic tanks and sewage treatment can

reduce point-source water pollution ~1/4 of homes in U.S. served by septic tanks most urban areas served by sewage treatment

plants some 1,200 cities have combined storm runoff

and sewer lines because it is cheaper; can overflow

sewer systems in the U.S. are estimated to cost $10 billion a year for 10 years to install, expand, and repair the aging sewer network

Fig. 20-15 Septic tank system

20-6 Preventing Surface Water Pollution septic tanks and sewage treatment, cont.

raw sewage generally undergoes one or two levels of treatment

primary sewage treatment removes grit, floating objects, and suspended solids

removes ~60% of suspended solids and 30–40% of organic wastes

secondary sewage treatment is a biological process where aerobic bacteria remove up to 90% of O2-demanding organic wastes

tertiary sewage treatment: removing specific pollutants

Fig. 20-16 Primary and secondary treatment


raw sewage treatment, cont. a combination of primary and secondary

treatment removes 95–97% of the suspended solids and

oxygen-demanding organic wastes 70% of most toxic metal compounds 70% of P, 50% of N, 5% of dissolved

salts most U.S. cities have combined plants 34 East Coast cities screen out floating

objects and discharge sewage into coastal waters


water is bleached to remove colors and then disinfected (usually chlorination) to kill disease-causing bacteria and some viruses

ozonation and use of ultraviolet light are increasing as methods of disinfection

20-6 Preventing Surface Water Pollution sewage sludge

sludge is a thick, gooey mixture of bacteria, solids, chemicals, and metals when industrial and household wastes are combined

some sludge undergoes anaerobic digestion to decompose organics and produce compost

~36% of these biosolids are used as fertilizer; rest is added to landfills or incinerated

removing infectious bacteria, toxins, and metals is expensive, seldom done in the U.S.

health problems?

Fig. 20-17 Problems with sludge

20-6 Preventing Surface Water Pollution preventing toxic chemicals from reaching

treatment plants would eliminate these from sludge and water that is discharged

require industries and businesses to remove toxic and hazardous wastes from water sent to sewage treatment plants

encourage reduction or elimination of toxic chemical use and waste

have households switch to waterless composting toilet systems maintained by professionals

20-6 Preventing Surface Water Pollution wetlands can be used to treat sewage

low-tech, low-cost alternative to expensive waste treatment plants

sewage -> sedimentation tanks -> oxidation ponds -> (1 month) artificial marsh

genetic engineering is developing a bioreactor where modified bacteria will consume pesticides

without large investments in building adequate sanitation facilities, more people will have inadequate sanitation

Fig. 20-18 Wastewater garden

20-6 Preventing Surface Water Pollution water pollution laws have significantly

improved water quality in U.S. improvements:

1992 to 2002, communities served by water systems meeting federal guidelines increased from 79% to 94%

fishable and swimmable streams increased from 36% to 60% of those tested

topsoil loss through runoff was cut by 111 billion metric tons annually (%?)

annual wetland losses decreased by 80%

20-6 Preventing Surface Water Pollution water pollution laws have significantly

improved water quality in U.S., cont. problem areas:

in 2000, 40% of streams and 45% of lakes surveyed were too polluted for swimming or fishing

animal waste and waste lagoons fish unsafe to eat (pesticides, Hg, etc.) in 2003, the EPA found that >50% of the

6,000 largest industrial facilities have been illegally discharging wastes into waterways

20-6 Preventing Surface Water Pollution a 2001 report by EPA’s inspector general

calls for strengthening the Clean Water Act increased funding, increased authority to

control non-point pollution, modernizing monitoring system, increasing compliance with the law

integrating watershed and airshed planning to protect ground and surface water sources

halt the loss of wetlands; increase standards for wetland restoration; and create new wetlands before filling existing ones

farmers feel they should be compensated for property value losses that result from federal regulations protecting wetlands

20-7 Drinking Water Quality 20% of people lack safe drinking water

95% of people in developed countries and 74% of people in developing countries have access to clean drinking water

the UN estimates $23 billion/yr for 8–10 yr to bring clean drinking water to those lacking it

centralized water treatment plants can provide safe drinking water; water is settled, filtered, and chlorinated

20-7 Drinking Water Quality the U.S. is upgrading water purification and

delivery systems hard to secure also difficult to adequately poison both chemical and biological indicators are

being developed to indicate contamination

20-7 Drinking Water Quality several simple, inexpensive ways for

individuals and villages to purify drinking water have been developed

exposure of contaminated water to intense sunlight in a clear plastic bottle kills bacteria

filtering water through cloth reduces risk of cholera

a small amount of chlorine in a plastic or clay storage vessel cuts the rate of diarrheal disease in half

20-7 Drinking Water Quality about 54 countries have standards for safe

drinking water levels have been established called maximum

contaminant levels for any pollutants that may adversely affect human health

privately owned wells don’t have to meet these standards

some want the standards to be strengthened certain industries want to weaken the Safe

Drinking Water Act (which industries?)

20-7 Drinking Water Quality some bottled water is not as pure as tap

water and costs much more bottled water is vastly more expensive than tap

water 1/4 is tap water 1/3 is contaminated with bacteria 1/5 is contaminated with organic chemicals

creates lots of waste manufacture releases toxic gases and liquids have home water tested be wary of companies claiming EPA approval

20-7 Drinking Water Quality we need to shift priorities to preventing and

reducing water pollution bottom-up political pressure on elected officials

has reduced point-source water pollution a shift needs to be made to how we can

prevent water pollution in the first place prevention of water pollution will take action

from individuals and groups to pressure elected officials

Fig. 20-19 Solutions

Fig. 20-20 What can you do?

` area iv: pollution iva3: water pollution. ` 20-1 types, effects, sources of water pollution l...

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