Water Pollution 21

8/6/2019 Water Pollution 21

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Water Pollution


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Point and Nonpoint Sources

NONPOINT SOURCES

Urban streets

Suburbandevelopment

Wastewatertreatmentplant

Rural homes

Cropland

Factory

Animal feedlot

POINTSOURCES


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Water pollution

Bacteria,Viruses,Protozoa, Parasitic worms

Oxygen demanding substances

Inorganic plant nutrients

Organic chemicals

Sediment or suspended matter

Thermal pollution

Genetic pollution


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Rainbow smelt1.04 ppm

Zooplankton0.123 ppm

Phytoplankton0.0025 ppm

Water0.000002 ppm

Herring gull124 ppm

Lake trout4.83 ppm

Herring gull eggs

124 ppm

BiologicalMagnification


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Pollution of Streams

Oxygen sag curveOxygen sag curve Oxygen sag curveOxygen sag curve

Fig. 21-4


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Pollution of Lakes

Eutrophication EutrophicationDischarge of untreated

municipal sewage(nitrates and phosphates)

Nitrogen compoundsproduced by cars

and factories

Discharge of treatedmunicipal sewage

(primary and secondarytreatment:

nitrates and phosphates)

Discharge ofdetergents

( phosphates)

Natural runoff(nitrates andphosphates

Manure runoffFrom feedlots(nitrates andPhosphates,

ammonia)

Dissolving ofnitrogen oxides

(from internal combustionengines and furnaces)

Runoff and erosion(from from cultivation,mining, construction,

and poor land use)

Runoff from streets,lawns, and construction

lots (nitrates andphosphates)

Lake ecosystemnutrient overloadand breakdown ofchemical cycling

Fig .22.7, p. 499


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Fig. 21-8, p. 502

Water well

Migratingvapor phase

Contaminant plume moveswith the groundwater

Free gasolinedissolves ingroundwater(dissolvedphase)

Groundwaterflow

Watertable

Gasolineleakage plume(liquid phase)

Leakingtank


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Groundwater Pollution: Causes

Coal stripmine runoff

Pumpingwell

Waste lagoon

Accidentalspills

Groundwater

flow

Confined aquifer

Discharge

Leakage from faultycasing

Hazardous waste injection well

Pesticides

Gasolinestation

Buried gasolineand solvent tank

Sewer

Cesspoolseptic tank

De-icingroad salt

Water pumping

well Landfill

Fig. 21-7


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Groundwater Pollution Prevention

Monitoring aquifersMonitoring aquifers

Strictly regulating hazardous wastedisposal

Strictly regulating hazardous wastedisposal

Storing hazardous materials aboveground

Storing hazardous materials aboveground


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Fig. 21-10, p. 505

Healthy zoneClear, oxygen-richwaters promote growth

of plankton and sea grasses,and support fish.

Oxygen-depleted zoneSedimentation and algaeovergrowth reduce sunlight,

kill beneficial sea grasses, useup oxygen, and degrade habitat.

Red tidesExcess nitrogen causesexplosive growth oftoxicmicroscopic algae,poisoning fish andmarine mammals.

FarmsRunoff of pesticides, manure, andfertilizers adds toxins and excessnitrogen and phosphorus.

Toxic sedimentsChemicals and toxicmetals contaminateshellfish beds, killspawning fish, andaccumulate in the tissuesof bottom feeders.

Construction sitesSediments are washed intowaterways, choking fish and plants,clouding waters, and blockingsunlight.

Urban sprawlBacteria and virusesfromsewers and septictanks contaminateshellfish beds

Oxygen-depletedzone

Closedbeach

CitiesToxic metalsand oil fromstreets andparking lotspollute waters;

IndustryNitrogen oxidesfrom autos andsmokestacks,toxic chemicals,and heavy metals ineffluents flow intobays and estuaries.

Closedshellfish beds


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Reducing Water Pollution through

Sewage Treatment

Primaryand Secondarysewage treatment.

Figure 21Figure 21--1616


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Technological Approach: Using

Wetlands to Treat Sewage((

((

45 centimeterlayer of limestonegravel coated with

decomposing bacteriaFirst concrete pool Second concrete pool

SewageSewage

Wetland typeWetland typeplantsplants

Wetland typeWetland typeplantsplants

TreatedTreatedwaterwater


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Global Outlook: Stream Pollution in

Developing Countries

Water in manyof

central China's rivers

are greenish black fromuncontrolled pollution

bythousands of

factories.



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Case Study: Indias Ganges River: Religion,

Poverty, and Health

Religious beliefs, cultural traditions, poverty, and

a large population interact to cause severe

pollution of the Gan

ges River in India.

Verylittle of the sewage is treated.

Hindu believe in cremating the dead to free the soul

and throwing the ashes in the holyGanges.

Some are too poor to afford the wood to fullycremate. Decomposing bodies promote disease and depletes DO.


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Case Study: Indias Ganges River: Religion,

Poverty, and Health

Daily, more than 1

million Hindus in India

bathe, drink from, or

carryout religious

ceremonies in the

highlypolluted Ganges

River.



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Drinking Water Quality

Safe Drinking

Water Act Safe Drinking

Water Act

Maximum contaminant levels Maximum contaminant levels

Bottled water Bottled water


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Is Bottled Water the Answer?

Some bottled water is not as pure as tap water

and costs much more.

1.4 million metric tons ofplastic bottles are

thrown away.

Fossil fuels are used to make plastic bottles.

The oil used to produce plastic bottles in the U.S. each

year would fuel 100,000 cars.


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Using Laws to Protect Drinking

Water

The U.N. estimates that 5.6 million Americansdrink water that does not meet EPA standards.

1 in 5 Americans drinks water from a treatmentplant that violated one or more safetystandard.

Industrypressures to weaken the Safe DrinkingAct:

Eliminate national tests and public notification ofviolations.

Allow rights to pollute ifprovider cannot afford tocomply.


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Fig. 21-19, p. 517

What Can You Do?

Water Pollution

F

ertilize garden and yard plants with manure or compostinstead of commercial inorganic fertilizer.

Minimize your use of pesticides.

Do not apply fertilizer or pesticides near a body of water.

Grow or buy organic foods.

Do not drink bottled water unless tests show that your tap

water is contaminated. Merely refill and reuse plastic bottles

with tap water.

Compost your food wastes.

Do not use water fresheners in toilets.

Do not flush unwanted medicines down the toilet.

Do not pour pesticides, paints, solvents, oil, antifreeze, or other

products containing harmful chemicals down the drain or

onto the ground.

Water Pollution 21

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