Water and Water PollutionWater and Water Pollution

Chapter 11Chapter 11

Water Conflicts in the Middle Water Conflicts in the Middle EastEast

Water shortages Water shortages

Nile River Nile River

Jordan BasinJordan Basin

Tigris and Euphrates riversTigris and Euphrates rivers

Peacefully solving the problemsPeacefully solving the problems

Fig. 11-1, p. 236

Water Conflicts in the Middle Water Conflicts in the Middle EastEast

Fig. 11-1, p. 236

Importance and Availability of Importance and Availability of WaterWater

Why is water so important?Why is water so important?

Earth as a watery world Earth as a watery world

Water as a wasted resourceWater as a wasted resource

Tiny fraction of Earth’ water is freshTiny fraction of Earth’ water is fresh

Hydrologic cycleHydrologic cycle

Water pollutionWater pollution

Water haves and have-notsWater haves and have-nots

Fig. 11-2, p. 238

All water Fresh water Readily accessible fresh water

Oceans andsaline lakes97.4%

Fresh water2.6%

Groundwater0.592%

Ice capsand glaciers1.984%

Soilmoisture0.005%

Biota0.0001%

Rivers0.0001%

Atmosphericwater vapor0.001%

0.014%

Lakes 0.007%

Earth’s Water BudgetEarth’s Water Budget

GroundwaterGroundwater

Zone of saturationZone of saturation

Water table Water table

AquifersAquifers

Natural rechargeNatural recharge

Evaporation and transpiration Evaporation

Stream

Infiltration

Watertable

Infiltration

Unconfined aquifer

Confined aquifer

Lake

Well requiring a pump

Flowingartesian well

Runoff

Precipitation

ConfinedRechargeArea

Recharge Unconfined Aquifer

Lesspermeable materialsuch as clay Confining impermeable rock layer

Unconfined Aquifer Recharge Area

Fig. 11-3, p. 239

Groundwater Systems Groundwater Systems

Use of Water ResourcesUse of Water Resources

Runoff use: about 54%Runoff use: about 54%

Freshwater use Freshwater use

US freshwater resourcesUS freshwater resources

Domestic, agricultural, and industrial useDomestic, agricultural, and industrial use

Fig. 11-4a, p. 240

Annual Annual Precipitation and Precipitation and

Water-deficit Water-deficit Regions of the Regions of the Continental US Continental US

Fig. 11-4a, p. 240

Average annual precipitation (centimeters)

Less than 41

41-81

81-22

More than 122

Annual Precipitation and Water-deficit Annual Precipitation and Water-deficit Regions of the Continental USRegions of the Continental US

Fig. 11-4b, p. 240

Acute shortage

Shortage

Adequate supply

Metropolitan regions with populationgreater than 1 million

Annual Precipitation and Water-deficit Annual Precipitation and Water-deficit Regions of the Continental USRegions of the Continental US

Fig. 11-5, p. 240

Highly likely conflict potential

Substantial conflict potential

Moderate conflict potential

Unmet rural water needs

Wash.

Oregon

Idaho

Nevada

California

Utah

Montana

Wyoming

Colo.

N.M.

N.D.

S.D.

Neb.

Kansas

Oak.

Texas

Water Hot Spots in Western StatesWater Hot Spots in Western States

Freshwater ShortagesFreshwater Shortages

Causes of water scarcity: dry climate and too many Causes of water scarcity: dry climate and too many peoplepeople

Stresses on world’s major river systemsStresses on world’s major river systems

1 of 6 people have no regular access to clean water1 of 6 people have no regular access to clean water

Poverty hinders access to waterPoverty hinders access to water

Hydrological povertyHydrological poverty

High None

Stress

Fig. 11-6, p. 241

Stress on World’s River BasinsStress on World’s River Basins

North America

Europe

Asia

Australia

Africa

South America

Hydrological PovertyHydrological Poverty

Fig. 11-7, p. 241

Politics and Ethics of WaterPolitics and Ethics of Water

Who should pay for the water?Who should pay for the water?

Public or private ownershipPublic or private ownership

Increasing Freshwater SuppliesIncreasing Freshwater Supplies

Dams and reservoirsDams and reservoirs

Extracting groundwaterExtracting groundwater

DesalinationDesalination

Reducing water wasteReducing water waste

Importing foodImporting food

Importing waterImporting water

Catching precipitationCatching precipitation

Fig. 11-8, p. 243

Tradeoffs of Large Dams and Tradeoffs of Large Dams and ReservoirsReservoirs

Large lossesof water throughevaporation

Flooded land destroys forests or cropland anddisplaces people

Downstreamflooding is reduced

Downstream cropland and estuaries are deprived of nutrient-rich silt

Reservoir is useful forrecreation and fishing

Can producecheap electricity(hydropower)

Migration andspawning ofsome fish aredisrupted

Provides waterfor year-roundirrigation ofcropland

Fig. 11-9, p. 243

• Deliver nutrients to sea to help sustaincoastal fisheries

• Deposit silt that maintains deltas

• Purify water

• Renew and renourish wetlands

• Provide habitats for wildlife

N a t u r a l C a p i t a l

Ecological Services of Rivers

Ecological Services of RiversEcological Services of Rivers

Fig. 11-10, p. 244

North BayAqueduct

South BayAqueduct

California Aqueduct

CALIFORNIA

NEVADA UTAH

MEXICO

Central ArizonaProject

Colorado RiverAqueduct

Los AngelesAqueduct

Shasta Lake

Oroville Dam andReservoir

FeatherRiver

Lake Tahoe

Sacramento

Fresno

Hoover Damand Reservoir(Lake Mead)

Salton SeaPhoenix

Tucson

ARIZONA

ColoradoRiver

SacramentoRiver

San Francisco

San Luis Damand Reservoir

Santa Barbara

Los Angeles

San Diego

California Water Project and California Water Project and Central Arizona ProjectCentral Arizona Project

San Joaquin V

alley

Aral Sea DisasterAral Sea Disaster Large-scale water transfers in dry central AsiaLarge-scale water transfers in dry central Asia

SalinitySalinity

Wetland destruction and wildlifeWetland destruction and wildlife

Fish extinctions and fishingFish extinctions and fishing

Wind-blown saltWind-blown salt

Water pollutionWater pollution

Climatic changesClimatic changes

Restoration effortsRestoration efforts

Shrinking Aral SeaShrinking Aral Sea

Fig. 11-11, p. 245

Stranded Ship at the Aral SeaStranded Ship at the Aral Sea

Fig. 11-12, p. 245

Trade-Offs

Withdrawing Groundwater

Advantages Disadvantages

Good source of water fordrinking and irrigation

Available year-round

Exists almost everywhere

Renewable if not over-pumped or contaminated

No evaporation losses

Cheaper to extract than most surface waters

Aquifier depletion from over-pumping

Sinking of land (subsidence)when water removed

Polluted aquifiers unusablefor decades or centuries

Saltwater intrusion intodrinking water supplies nearcoastal areas

Reduced water flows intostreams, lakes, estuaries, and wetlands

Increased cost, energy use,and contamination fromdeeper wells

Fig. 11-13, p. 246

Tradeoffs of Withdrawing Tradeoffs of Withdrawing GroundwaterGroundwater

Fig. 11-14, p. 246

GroundwaterOverdrafts:

High

Moderate

Minor or none

Aquifer DepletionAquifer Depletion

Major irrigationwell

Well contaminatedwith saltwater

SaltwaterIntrusion Normal

Interface

Freshgroundwater

aquifer

Interface

Saltwater

Sea LevelWater table

Seafloor

Fig. 11-15, p. 247

Saltwater Intrusion into Coastal Saltwater Intrusion into Coastal Water WellsWater Wells

Interface

Fig. 11-16, p. 247

Solutions

Groundwater Depletion

Prevention Control

Waste less water

Subsidize waterconservation

Ban new wells in aquifiers near surface waters

Buy and retire ground-water withdrawal rights in critical areas

Do not grow water-intensive crops in dry areas

Reduce birth rates

Raise price of water todiscourage waste

Tax water pumped from Wells near surface water

Set and enforce minimum stream flow levels

Groundwater DepletionGroundwater Depletion

DesalinationDesalination

Removal of salts from ocean or brackish waters to Removal of salts from ocean or brackish waters to produce useable waterproduce useable water

Distillation methodDistillation method

Reverse osmosis methodReverse osmosis method

Used in 120 countriesUsed in 120 countries

Major problems: high cost and a lot of brine wastesMajor problems: high cost and a lot of brine wastes

Research is neededResearch is needed

Reducing Water WasteReducing Water Waste

Benefits of water conservationBenefits of water conservation

Reduce leakage and save waterReduce leakage and save water

Water prices, government subsidies, and Water prices, government subsidies, and wastewaste

Improve irrigationImprove irrigation

Using less water in homes and businessesUsing less water in homes and businesses

Fig. 11-17, p. 249

Gravity Flow(efficiency 60% and 80%

with surge valves)

Water usually comes from an aqueduct system or a

nearby river.

Drip Irrigation(efficiency 90-95%)

Above- or below-ground pipes or tubes deliver water to individual plant roots.

Center Pivot(efficiency 80% with low-pressure sprinkler

and 90–95% with LEPA sprinkler)

Water usually pumped from underground and sprayed from mobile boom with sprinklers.

Major Types of Irrigation SystemsMajor Types of Irrigation Systems

Fig. 11-18, p. 250

Solutions

Reducing Irrigation Water Waste

•Lining canals bring water to irrigation ditches

•Leveling fields with lasers

•Irrigating at night to reduce evaporation

•Using soil and satellite sensorsand computer systems to monitor soil moisture and add water only when necessary

•Polyculture

•Organic Farming

•Growing water-efficient crops using drought-resistant and salt tolerant crops varieties

•Irrigating with treated urban waste water

•Importing water-intensive crops and meat

Reducing Irrigation Water WasteReducing Irrigation Water Waste

Fig. 11-19, p. 250

Reducing Water Waste

Solutions

•Redesign manufacturing processes

•Landscape yards with plants that require little water

•Use drip irrigation

•Fix water leaks

•Use water meters and charge for all municipal water use

•Use waterless composting toilets

•Require water conservation in water-short cities

•Use water-saving toilets, showerheads, and front-loading clothes washers

•Collect and reuse household water to irrigate lawns and nonedible plants

•Purify and reuse water for houses, apartments, and office buildings

Reducing Water WasteReducing Water Waste

Using Water More SustainablyUsing Water More Sustainably

Blue revolutionBlue revolution

Cut wasteCut waste

Raise water pricesRaise water prices

Drier waste treatmentDrier waste treatment

Preserve forestsPreserve forests

Slow population growthSlow population growth

Fig. 11-20, p. 251

• Not depleting aquifers

• Preserving ecological health of aquatic systems

• Preserving water quality

• Integrated watershed management

• Agreements among regions and countries sharing surface water resources

• Outside party mediation of water disputes between nations

• Marketing of water rights

• Raising water prices

• Wasting less water

• Decreasing government subsides for supplying water

• Increasing government subsides for reducing water waste

• Slowing population growth

SolutionsSustainable Water Use

Sustainable Water UseSustainable Water Use

Fig. 11-21, p. 251

• Use water-saving toilets, showerheads, and faucet aerators

• Shower instead of taking baths, and take short showers.

• Repair water leaks.

• Turn off sink faucets while brushing teeth, shaving, or washing.

• Wash only full loads of clothes or use the lowest possible water-level setting for smaller loads.

• Wash a car from a bucket of soapy water, and use the hose for rinsing only.

• If you use a commercial car wash, try to find one that recycles its water.

• Replace your lawn with native plants that need little if any watering.

• Water lawns and garden in the early morning or evening.

• Use drip irrigation and mulch for gardens and flowerbeds.

• Use recycled (gray) water for watering lawns and houseplants and for washing cars.

What Can You Do?Water Use and Waste

What Can We Do?What Can We Do?

Benefits of FloodplainsBenefits of Floodplains

Highly productive wetlandsHighly productive wetlands

Provide natural flood and erosion controlProvide natural flood and erosion control

Maintain high water qualityMaintain high water quality

Recharge groundwaterRecharge groundwater

Fertile soilsFertile soils

Nearby rivers for use and recreationNearby rivers for use and recreation

Flatlands for urbanization and farmingFlatlands for urbanization and farming

Dangers of Floodplains and FloodsDangers of Floodplains and Floods

Deadly and destructiveDeadly and destructive

Human activities worsen floodsHuman activities worsen floods

Failing dams and water diversionFailing dams and water diversion

BangladeshBangladesh

Before and During a Flood in St. Before and During a Flood in St. Louis, MissouriLouis, Missouri

Fig. 11-22, p. 252

Fig. 11-23a, p. 253

Oxygenreleased byvegetation

Diverseecological

habitatEvapotranspiration

Trees reduce soilerosion from heavyrain and wind

AgriculturallandSteady

river flow

Leaf litterimprovessoil fertility

Tree roots stabilize soil and aid water flow

Vegetation releaseswater slowly andreduces flooding

Forested Hillside

Flooding After Deforestation of a Flooding After Deforestation of a HillsideHillside

Fig. 11-23b, p. 253

Tree plantation

Evapotranspiration decreases

Ranching accelerates soil erosion by water and wind

Winds removefragile topsoil

Gullies andlandslides

Heavy rain leaches nutrients from soil and erodes topsoil

Rapid runoffcauses flooding

After Deforestation

Roadsdestabilizehillsides

Agriculture landis flooded andsilted up

Silt from erosion blocks rivers andreservoirs and causes flooding downstream

Flooding After Deforestation of a Flooding After Deforestation of a HillsideHillside

Table 11-1, p. 254

Reducing Flood RisksReducing Flood Risks

ChannelizationChannelization

Levees (floodwalls)Levees (floodwalls)

DamsDams

Protect and restore wetlandsProtect and restore wetlands

Identify and manage flood-prone areasIdentify and manage flood-prone areas

Precautionary approachPrecautionary approach

Water Pollution: Types, Effects, Water Pollution: Types, Effects, and Sourcesand Sources

What is water pollution?What is water pollution?

Major types of pollutants, sources and effects (Table 11-1, p. 254)Major types of pollutants, sources and effects (Table 11-1, p. 254)

Point and nonpoint sourcesPoint and nonpoint sources

Is the water safe to drink?Is the water safe to drink?

Polluted StreamsPolluted Streams Factors influencing stream recovery from pollutionFactors influencing stream recovery from pollution

Oxygen sag curveOxygen sag curve

Importance of wastewater treatment plants Importance of wastewater treatment plants

Improvements in quality of US streamsImprovements in quality of US streams

Cuyahoga River of OhioCuyahoga River of Ohio

Effect of regulations in USEffect of regulations in US

Pressures from US citizen groupsPressures from US citizen groups

Problems with nonpoint, accidental and illegal releasesProblems with nonpoint, accidental and illegal releases

Problems in developing countriesProblems in developing countries

Clean ZoneDecomposition

Zone

Septic ZoneRecovery

Zone

Clean Zone

Normal clean water organisms(trout, perch, bass,

mayfly, stonefly)

Trash fish(carp, gar,leeches)

Fish absent, fungi,sludge worms,bacteria

(anaerobic)

Trash fish(carp, gar,leeches)

Normal clean water organisms(trout, perch, bass,

mayfly, stonefly)

8 ppmDissolved oxygen (ppm)

Biological oxygendemand

8 ppmTypes of

organisms

Fig. 11-24, p. 256

Pollution in StreamsPollution in Streams

Lake PollutionLake Pollution Dilution less effective than with streamsDilution less effective than with streams

Stratification in lakes and relatively little flow hinder rapid dilution of Stratification in lakes and relatively little flow hinder rapid dilution of pollutantspollutants

Lakes more vulnerable to pollutants than streamsLakes more vulnerable to pollutants than streams

How pollutants enter lakesHow pollutants enter lakes

Eutrophication: causes and effectsEutrophication: causes and effects

Oligotrophic and eutrophic lakesOligotrophic and eutrophic lakes

Cultural eutrophicationCultural eutrophication

Preventing or removing eutrophicationPreventing or removing eutrophication

Oligotrophic and Eutrophic Oligotrophic and Eutrophic LakesLakes

Fig. 11-25, p. 257

Groundwater Pollution: Causes Groundwater Pollution: Causes and Persistenceand Persistence

Sources of groundwater pollutionSources of groundwater pollution

Slow flowing: slow dilution and dispersionSlow flowing: slow dilution and dispersion

Consequences of lower dissolved oxygenConsequences of lower dissolved oxygen

Fewer bacteria to decompose wastesFewer bacteria to decompose wastes

Cooler temperatures: slow down chemical reactionsCooler temperatures: slow down chemical reactions

““Degradable” and nondegradable wastes in groundwaterDegradable” and nondegradable wastes in groundwater

Coal strip mine runoff

Pumping well

Waste lagoon

Accidental spills

Groundwater flow

Confined aquifer

Discharge

Leakage from faulty casing

Hazardous waste injection wellPesticides

and fertilizers

Gasoline station

Buried gasoline and solvent tank

SewerCesspool septic tank

De-icing road salt

Unconfined freshwater aquifer

Confined freshwater aquifer

Water pumping well

Landfill

Polluted air

Fig. 11-26, p. 258

Groundwater PollutionGroundwater Pollution

Extent of Groundwater PollutionExtent of Groundwater Pollution

Not much is known about groundwater pollutionNot much is known about groundwater pollution

Organic contaminants, including fuel leaksOrganic contaminants, including fuel leaks

ArsenicArsenic

Protecting groundwater: Prevention is bestProtecting groundwater: Prevention is best

Pump nanoparticles of inorganic compounds to remove pollutants (may be the cheapest, easiest, and most effective method but is still being developed)

Find substitutes for toxic chemicalsKeep toxic chemicals out of the environment

Install monitoring wells nearlandfills and underground tanks

Require leak detectors on underground tanks

Ban hazardous waste disposalin landfills and injection wells

Inject microorganisms to clean up contamination (less expensive but still costly)

Store harmful liquids in aboveground tanks with leak detection and collection systems

Prevention Cleanup

Pump to surface, clean, and return to aquifer (very expensive)

Solutions

Groundwater Pollution

Fig. 11-27, p. 259

Preventing and Cleaning Up Preventing and Cleaning Up Pollution in GroundwaterPollution in Groundwater

Ocean PollutionOcean Pollution

How much pollution can oceans tolerate?How much pollution can oceans tolerate?

Some pollutants degrade and dilute in oceansSome pollutants degrade and dilute in oceans

Ocean dumping controversiesOcean dumping controversies

Fig. 11-28, p. 260

IndustryNitrogen oxides from autos and smokestacks; toxicchemicals, and heavymetals in effluents flow into bays and estuaries.

CitiesToxic metals andoil from streets andparking lots pollutewaters; sewageadds nitrogen andphosphorus.

Urban sprawlBacteria and viruses from sewers and septic tanks contaminate shellfish beds and close beaches; runoff of fertilization from lawns adds nitrogen and phosphorus.

Construction sitesSediments are washed into waterways,choking fish and plants, cloudingwaters, and blocking sunlight.

FarmsRun off of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus.

Red tidesExcess nitrogen causes explosive growth of toxic microscopic algae, poisoning fish and marine mammals.

Healthy zoneClear, oxygen-rich waterspromote growth of planktonand sea grasses, and support fish.

Toxic sedimentsChemicals and toxic metalscontaminate shellfish beds,kill spawning fish, andaccumulate in the tissuesof bottom feeders.

Closed shellfish beds

Closedbeach Oxygen-depleted

zone

Coastal Water PollutionCoastal Water Pollution

Oxygen-depleted zoneSedimentation and algae overgrowth reduce sunlight, kill beneficial sea grasses, use up oxygen, and degrade habitat.

Fig. 11-29, p. 261

MississippiRiver Basin

MissouriRiver

OhioRiver

MississippiRiver

LOUISIANAMississippi

River

Depleted Oxygen

Gulf of Mexico

Oxygen-depleted Water in Oxygen-depleted Water in the Gulf of Mexicothe Gulf of Mexico

Chesapeake BayChesapeake Bay

Largest US estuaryLargest US estuary

Pollution “sink”Pollution “sink”

Oxygen depletionOxygen depletion

Chesapeake Bay Chesapeake Bay ProgramProgram

Fig. 11-30, p. 261

Fig. 11-30, p. 261Drainagebasin No oxygen Low concentrations

of oxygen

PENNSYLVANIA

NEW YORK

WESTVIRGINIA

MARYLAND

DELAWARE

NEWJERSEY

ATLANTICOCEAN

VIRGINIA

Cooperstown

Harrisburg

Baltimore

Washington

Richmond

NorfolkChesapeake Bay

Chesapeake BayChesapeake Bay

Effects of Oil on Ocean LifeEffects of Oil on Ocean Life Crude and refined petroleumCrude and refined petroleum

Tanker accidents and blowoutsTanker accidents and blowouts

Exxon ValdezExxon Valdez

Volatile hydrocarbons kill larvaeVolatile hydrocarbons kill larvae

Tar-like globs coat birds and marine mammalsTar-like globs coat birds and marine mammals

Oil destroys insulation and buoyancyOil destroys insulation and buoyancy

Heavy oil sinks and kills bottom organismsHeavy oil sinks and kills bottom organisms

Coral reefs dieCoral reefs die

Slow recoverySlow recovery

Oil slicks ruin beachesOil slicks ruin beaches

Limited effectiveness of clean up methodsLimited effectiveness of clean up methods

Prevention Cleanup

Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters

Reduce input of toxic pollutants

Separate sewage and storm lines

Regulate coastal development

Recycle used oil

Require double hulls for oil tankers

Require at least secondary treatment of coastal sewage

Use wetlands, solar-aquatic, orother methods to treat sewage

Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful byproducts(still under development)

Protect sensitive areas from development, oil drilling, and oil shipping

Ban ocean dumping of sludge and hazardous dredged material

Improve oil-spill cleanup capabilities

Solutions

Coastal Water Pollution

Fig. 11-31, p. 263

Preventing and Cleaning Up Preventing and Cleaning Up Pollution in Coastal WatersPollution in Coastal Waters

Preventing Nonpoint Source Preventing Nonpoint Source PollutionPollution

Mostly agricultural wastesMostly agricultural wastes

Use vegetation to reduce soil erosionUse vegetation to reduce soil erosion

Reduce fertilizer useReduce fertilizer use

Use plant buffer zones around fieldsUse plant buffer zones around fields

Integrated pest management: Only use pesticides when necessaryIntegrated pest management: Only use pesticides when necessary

Use plant buffers around animal feedlotsUse plant buffers around animal feedlots

Keep feedlots away from slopes, surface water and flood zonesKeep feedlots away from slopes, surface water and flood zones

Laws for Reducing Point Source Laws for Reducing Point Source PollutionPollution

Clean Water ActClean Water Act

Water Quality ActWater Quality Act

Sewage Treatment SystemsSewage Treatment Systems Sewage treatment in rural and suburban areasSewage treatment in rural and suburban areas

Septic tanksSeptic tanks

Primary (physical) sewage treatmentPrimary (physical) sewage treatment

Secondary (biological) sewage treatmentSecondary (biological) sewage treatment

Urban sewage treatment (Clean Water Act)Urban sewage treatment (Clean Water Act)

Sewage treatment facilities in many cities fail to meet federal Sewage treatment facilities in many cities fail to meet federal standardsstandards

Bleaching and disinfectionBleaching and disinfection

Disinfectants: chlorine, ozone, and ultraviolet radiationDisinfectants: chlorine, ozone, and ultraviolet radiation

Fig. 11-32, p. 264

Typical Septic Tank SystemTypical Septic Tank System

Householdwastewater

Perforated pipe

Distribution box (optional)

Septic tank with manhole (for cleanout)

Drainfield

Vent pipe

Nonperforated pipe

Gravel orcrushedstone

Primary and Secondary Sewage Primary and Secondary Sewage TreatmentTreatment

Fig. 11-33, p. 265

Raw sewagefrom sewers

Bar screen Grit chamber Settling tank Aeration tank Settling tankChlorinedisinfection tank

Sludge

Sludge digester

Activated sludge

Air pump

(kills bacteria)

To river, lake,

or ocean

Sludge drying bed

Disposed of in landfill or ocean or applied to cropland, pasture, or rangeland

Primary Secondary

Improving Sewage TreatmentImproving Sewage Treatment

Systems that exclude hazardous wastesSystems that exclude hazardous wastes

Non-hazardous substitutesNon-hazardous substitutes

Composting toilet systemsComposting toilet systems

Working with nature to treat sewageWorking with nature to treat sewage

Using wetlands to treat sewageUsing wetlands to treat sewage

Ecological Wastewater TreatmentEcological Wastewater Treatment

Fig. 11-34, p. 265

Should the Clean Water Act be Should the Clean Water Act be Strengthened?Strengthened?

Yes: environmentalistsYes: environmentalists

No: farmers, libertarians, manufacturers, No: farmers, libertarians, manufacturers, and developersand developers

State and local officials want more State and local officials want more discretiondiscretion

Drinking Water QualityDrinking Water Quality

Purification of urban drinking waterPurification of urban drinking water

Purification of drinking water in Purification of drinking water in developing countriesdeveloping countries

Bottled waterBottled water

Fig. 11-35, p. 267

Solutions

Water Pollution

• Prevent groundwater contamination

• Greatly reduce nonpoint runoff

• Reuse treated wastewater for irrigation

• Find substitutes for toxic pollutants

• Work with nature to treat sewage

• Practice four R's of resource use (refuse,

reduce, recycle, reuse)

• Reduce resource waste

• Reduce air pollution

• Reduce poverty

• Reduce birth rates

Reducing Water PollutionReducing Water Pollution

Fig. 11-36, p. 268

What Can You Do?

Water Pollution

• Fertilize your garden and yard plants with

manure or compost instead of commercial

inorganic fertilizer.• Minimize your use of pesticides.• Never apply fertilizer or pesticides near a body

of water.• Grow or buy organic foods.• 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.

What Can We Do?What Can We Do?