3Lake Washington Puget Sound Seattle Figure 20.1 The Seattle, Washington (USA) area. Seattle was founded on the shore of Puget Sound and quickly expanded eastward toward Lake Washington.Fig. 20-1, p. 531
4Core Case Study: Lake Washington Sewage dumped into Lake Washington1955: Edmondson discovered cyanobacteria in the lakeRole of phosphorusPublic pressure led to cleanup of the lakeNew pollution challenges
620-1 What Are the Causes and Effects of Water Pollution? Concept 20-1A Water pollution causes illness and death in humans and other species and disrupts ecosystems.Concept 20-1B The chief sources of water pollution are agricultural activities, industrial facilities, and mining, but growth in population and resource use make it increasingly worse.
7Water Pollution Comes from Point and Nonpoint Sources (1) Located at specific placesEasy to identify, monitor, and regulateExamples
8Water Pollution Comes from Point and Nonpoint Sources (2) Broad, diffuse areasDifficult to identify and controlExpensive to clean upExamples
9Water Pollution Comes from Point and Nonpoint Sources (3) Agriculture activities: leading cause of water pollutionSediment eroded from the landsFertilizers and pesticidesBacteria from livestock and food processing wastesIndustrial facilitiesMining
10Water Pollution Comes from Point and Nonpoint Sources (4) Other sources of water pollutionParking lotsHuman-made materialsE.g., plasticsClimate change due to global warming
11Point Source of Polluted Water in Gargas, France
12Nonpoint Sediment from Unprotected Farmland Flows into Streams
13Major Water Pollutants Have Harmful Effects Infectious disease organisms: contaminated drinking waterThe World Health Organization (WHO)3 Million people die every year, mostly under the age of 5
15Common Diseases Transmitted to Humans through Contaminated Drinking Water
16Science Focus: Testing Water for Pollutants (1) Variety of tests to determine water quality:Coliform bacteria: Escherichia coli, significant levelsLevel of dissolved oxygen (DO)Chemical analysis
17Science Focus: Testing Water for Pollutants (2) Indicator speciesExamplesBacteria and yeast glow in the presence of a particular toxic chemicalColor and turbidity of the water
18Water Quality as Measured by Dissolved Oxygen Content in Parts per Million
19Water Quality DO (ppm) at 20°C Good 8–9 Slightly polluted 6.7–8 Moderately polluted4.5–6.7Heavily pollutedFigure 20.AWater quality as measured by dissolved oxygen (DO) content in parts per million (ppm) at 20 °C (68 °F). Only a few fish species can survive in water with less than 4 ppm of dissolved oxygen at this temperature. Some warmer water species have evolved ways to tolerate low DO levels better than cold water species can. Question: Would you expect the dissolved oxygen content of polluted water to increase or decrease if the water is heated? Explain.4–4.5Gravely pollutedBelow 4Fig. 20-A, p. 535
2020-2 What Are the Major Water Pollution Problems in Streams and Lakes? Concept 20-2A While streams are extensively polluted worldwide by human activities, they can cleanse themselves of many pollutants if we do not overload them or reduce their flows.Concept 20-2B Addition of excessive nutrients to lakes from human activities can disrupt lake ecosystems, and prevention of such pollution is more effective and less costly than cleaning it up.
21Streams Can Cleanse Themselves If We Do Not Overload Them DilutionBiodegradation of wastes by bacteria takes timeOxygen sag curve
22Dilution and Decay of Degradable, Oxygen-Demanding Wastes in a Stream
23Point source Normal clean water organisms (Trout, perch, bass, mayfly, stonefly)Pollution-tolerant fishes (carp, gar)Fish absent, fungi, sludge worms,bacteria (anaerobic)Pollution-tolerant fishes (carp, gar)Normal clean water organisms (Trout, perch, bass,mayfly, stonefly)8 ppmTypes of organisms8 ppmDissolved oxygen (ppm)Figure 20.5Natural capital: dilution and decay of degradable, oxygen-demanding wastes (or heated water) in a stream, showing the oxygen sag curve (blue) and the curve of oxygen demand (red). Depending on flow rates and the amount of biodegradable pollutants, streams recover from oxygen-demanding wastes and from injection of heated water if they are given enough time and are not overloaded (Concept 20-2A). See an animation based on this figure at CengageNOW™. Question: What would be the effect of putting another biodegradable waste discharge pipe to the right of the one in this picture?Clean ZoneBiochemical oxygen demandRecovery ZoneSeptic ZoneDecomposition ZoneClean ZoneFig. 20-5, p. 536
24Stream Pollution in Developed Countries 1970s: Water pollution control lawsSuccessful water clean-up storiesOhio Cuyahoga River, U.S.Thames River, Great BritainContamination of toxic inorganic and organic chemicals by industries and mines
25Individuals Matter: The Man Who Planted Trees to Restore a Stream John Beal: restoration of Hamm Creek, Seattle, WA, U.S.Planted treesPersuaded companies to stop dumpingRemoved garbage
26Global Outlook: Stream Pollution in Developing Countries Half of the world’s 500 rivers are pollutedUntreated sewageIndustrial wasteIndia’s riversChina’s rivers
27Girl Sits on the Edge of a Road beside a Stream Loaded with Raw Sewage in Iraq
28Natural Capital Degradation: Highly Polluted River in China
29Trash Truck Disposing of Garbage into a River in Peru
30Case Study: India’s Ganges River: Religion, Poverty, Population Growth, and Health (1) Holy river: religious customsSewageHuman remainsGovernment interventionWaste treatment plantsCrematoriums
31Case Study: India’s Ganges River: Religion, Poverty, Population Growth, and Health (2) Adding to the pollutionReligious customPainted statuesGlobal warmingGangotri Glacier
33Low Water Flow and Too Little Mixing Makes Lakes Vulnerable to Water Pollution Less effective at diluting pollutants than streamsStratified layersLittle vertical mixingLittle of no water flow
34Cultural Eutrophication Is Too Much of a Good Thing (1) Oligotrophic lakeLow nutrients, clear waterCultural eutrophication
35Cultural Eutrophication Is Too Much of a Good Thing (2) During hot weather or droughtsAlgal bloomsIncreased bacteriaMore nutrientsAnaerobic bacteriaThen what?
36Cultural Eutrophication Is Too Much of a Good Thing (3) Prevent or reduce cultural eutrophicationRemove nitrates and phosphatesDiversion of lake waterClean up lakesRemove excess weedsUse herbicides and algaecides; down-side?Pump in air
37Revisiting Lake Washington and Puget Sound Severe water pollution can be reversedCitizen action combined with scientific researchGood solutions may not work foreverWastewater treatment plant effluents sent into Puget SoundNow what’s happening?
38Case Study: Pollution in the Great Lakes (1) 1960s: Many areas with cultural eutrophication1972: Canada and the United States: Great Lakes pollution control programWhat was done?Problems still existRaw sewageNonpoint runoff of pesticides and fertilizersBiological pollutionAtmospheric deposition of pesticides and Hg
39Case Study: Pollution in the Great Lakes (2) 2007 State of the Great Lakes reportNew pollutants foundWetland loss and degradation; significance?Declining of some native speciesNative carnivorous fish species decliningWhat should be done?
4220-3 Pollution Problems Affecting Groundwater, Other Water Sources Concept 20-3A Chemicals used in agriculture, industry, transportation, and homes can spill and leak into groundwater and make it undrinkable.Concept 20-3B There are simple ways and complex ways to purify drinking water, but protecting it through pollution prevention is the least expensive and most effective strategy.
43Ground Water Cannot Cleanse Itself Very Well (1) Source of drinking waterCommon pollutantsFertilizers and pesticidesGasolineOrganic solventsPollutants dispersed in a widening plume
44Ground Water Cannot Cleanse Itself Very Well (2) Slower chemical reactions in groundwater due toSlow flow: contaminants not dilutedLess dissolved oxygenFewer decomposing bacteriaHow long will it take to cleans itself ofSlowly degradable wastesE.g., DDTNondegradable wastesE.g., Pb and As
45Principal Sources of Groundwater Contamination in the U.S.
46Hazardous waste injection well Pesticides and fertilizers Polluted airHazardous waste injection wellPesticides and fertilizersDeicing road saltCoal strip mine runoffBuried gasoline and solvent tanksGasoline stationCesspool, septic tankPumping wellWater pumping wellWaste lagoonSewerLandfillAccidental spillsLeakage from faulty casingFigure 20.11Natural capital degradation: principal sources of groundwater contamination in the United States (Concept 20-3A). Another source is saltwater intrusion from excessive groundwater withdrawal in coastal areas. (Figure is not drawn to scale.) Question: What are three sources shown in this picture that might be affecting groundwater in your area?DischargeUnconfined freshwater aquiferConfined aquiferConfined freshwater aquiferGroundwater flowFig , p. 542
47Groundwater Contamination from a Leaking Gasoline Tank
48Free gasoline dissolves in groundwater (dissolved phase) Leaking tankAquiferBedrockWater tableFigure 20.12Natural capital degradation: groundwater contamination from a leaking gasoline tank. As the contaminated water spreads from its source in a widening plume, it can be extracted by wells used to provide water for drinking and irrigation.Groundwater flowFree gasoline dissolves in groundwater (dissolved phase)Gasoline leakage plume (liquid phase)Migrating vapor phaseWater wellContaminant plume moves with the groundwaterFig , p. 543
49Groundwater Pollution Is a Serious Threat China: many contaminated or overexploited aquifersU.S.: FDA reports of toxins found in many aquifersWhat about leaking underground storage tanks:GasolineOilMethyl tertiary butyl ether (MTBE)Nitrate ions
50Case Study: A Natural Threat from Arsenic in Groundwater Source of As in the groundwaterHuman health hazards: cancerSkinLungsBladder2006 research: Rice University, TX, U.S.Purification system to remove As
51Pollution Prevention Is the Only Effective Way to Protect Groundwater Prevent contamination of groundwaterCleanup: expensive and time consuming
52Solutions: Groundwater Pollution, Prevention and Cleanup
53SOLUTIONS Groundwater Pollution Prevention Cleanup Find substitutes for toxic chemicalsPump to surface, clean, and return to aquifer (very expensive)Keep toxic chemicals out of the environmentInstall monitoring wells near landfills and underground tanksInject microorganisms to clean up contamination (less expensive but still costly)Require leak detectors on underground tanksFigure 20.13Methods for preventing and cleaning up contamination of groundwater (Concept 20-3B). Question: Which two of the preventive solutions (left) do you think are the most important? Why?Ban hazardous waste disposal in landfills and injection wellsPump nanoparticles of inorganic compounds to remove pollutants (still being developed)Store harmful liquids in aboveground tanks with leak detection and collection systemsFig , p. 545
54There Are Many Ways to Purify Drinking Water Reservoirs and purification plantsProcess sewer water to drinking waterExpose clear plastic containers to sunlight (UV)NanofiltersThe LifeStraw
55The LifeStraw: Personal Water Purification Device
56Case Study: Protecting Watersheds Instead of Building Water Purification Plants New York City waterReservoirs in the Catskill MountainsProtect the watershed instead of water purification plants
57Using Laws to Protect Drinking Water Quality 1974: U.S. Safe Drinking Water ActSets maximum contaminant levels for any pollutants that affect human healthHealth scientists: strengthen the lawWater-polluting companies: weaken the law
58Is Bottled Water the Answer? U.S.: some of the cleanest drinking waterBottled waterSome from tap water40% bacterial contaminationFuel cost to manufacture the plastic bottlesRecycling of the plasticGrowing back-to-the-tap movement
6020-4 What Are the Major Water Pollution Problems Affecting Oceans? Concept 20-4A The great majority of ocean pollution originates on land and includes oil and other toxic chemicals and solid wastes, which threaten aquatic species and other wildlife and disrupt marine ecosystems.Concept 20-4B The key to protecting the oceans is to reduce the flow of pollutants from land and air and from streams emptying into these waters.
61Ocean Pollution Is a Growing and Poorly Understood Problem (1) 2006: State of the Marine Environment80% of marine pollution originates on landSewageCoastal areas most affectedDeeper ocean watersDilutionDispersionDegradation
62Ocean Pollution Is a Growing and Poorly Understood Problem (2) Cruise line pollution: what is being dumped?U.S. coastal watersRaw sewageSewage and agricultural runoff: NO3- and PO43-Harmful algal bloomsOxygen-depleted zones
63Residential Areas, Factories, and Farms Contribute to Pollution of Coastal Waters
64Industry Nitrogen oxides from autos and smokestacks, toxic chemicals, and heavy metals in effluents flow into bays and estuaries.Cities Toxic metals and oil from streets and parking lots pollute waters; sewage adds nitrogen and phosphorus.Urban sprawlBacteria and viruses from sewers and septic tanks contaminate shellfish beds and close beaches; runoff of fertilizer from lawns adds nitrogen and phosphorus.Construction sitesSediments are washed into waterways, choking fish and plants, clouding waters, and blocking sunlight.FarmsRunoff 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.Closed shellfish bedsClosed beachOxygen-depleted zoneFigure 20.15Natural capital degradation: residential areas, factories, and farms all contribute to the pollution of coastal waters and bays. According to the U.N. Environment Programme, coastal water pollution costs the world $16 billion annually—more than $30,000 a minute—due to ill health and premature death. Question: What are three changes you could make in your lifestyle that might help to prevent this pollution?Toxic sedimentsChemicals and toxic metals contaminate shellfish beds, kill spawning fish, and accumulate in the tissues of bottom feeders.Oxygen-depleted zone Sedimentation and algae overgrowth reduce sunlight, kill beneficial sea grasses, use up oxygen, and degrade habitat.Healthy zoneClear, oxygen-rich waters promote growth of plankton and sea grasses, and support fish.Fig , p. 548
66Science Focus: Oxygen Depletion in the Northern Gulf Of Mexico Severe cultural eutrophicationOxygen-depleted zoneOverfertilized coastal areaPreventive measuresWill it reach a tipping point?
67A Large Zone of Oxygen-Depleted Water in the Gulf of Mexico Due to Algal Blooms
68Mississippi River Basin Missouri RiverMississippi River BasinOhio RiverMississippi RiverMSFigure 20.BNatural capital degradation: a large zone of oxygen-depleted water (containing less than 2 ppm dissolved oxygen) forms each year during the spring and summer in the Gulf of Mexico as a result of oxygen-depleting algal blooms. Evidence indicates that it is created mostly by huge inputs of nitrate (NO3−) plant nutrients from farms, cities, factories, and sewage treatment plants in the vast Mississippi River basin. The drawing (bottom left) based on a satellite image, shows the inputs of such nutrients into the Gulf of Mexico during the summer of In the image, reds and greens represent high concentrations of phytoplankton and river sediment. This problem was worsened by losses of wetlands, which would have filtered out some of these plant nutrients. Question: Can you think of a product you used today that was directly connected to this sort of pollution? (NASA)LALOUISIANAMississippi RiverTXDepleted oxygenGulf of MexicoGulf of MexicoFig. 20-B, p. 550
69Ocean Oil Pollution Is a Serious Problem (1) Crude and refined petroleumHighly disruptive pollutantsLargest source of ocean oil pollutionUrban and industrial runoff from land1989: Exxon Valdez, oil tanker2002: Prestige, oil tanker
70Ocean Oil Pollution Is a Serious Problem (2) Volatile organic hydrocarbonsKill many aquatic organismsTar-like globs on the ocean’s surfaceCoat animalsHeavy oil components sinkAffect the bottom dwellers
71Ocean Oil Pollution Is a Serious Problem (3) Faster recovery from crude oil than refined oilCleanup proceduresMethods of preventing oil spills
72Solutions: Coastal Water Pollution, Prevention and Cleanup
73SOLUTIONS Coastal Water Pollution Prevention Cleanup Reduce input of toxic pollutantsImprove oil-spill cleanup capabilitiesSeparate sewage and storm linesUse nanoparticles on sewage and oil spills to dissolve the oil or sewage (still under development)Ban dumping of wastes and sewage by ships in coastal watersBan ocean dumping of sludge and hazardous dredged materialFigure 20.17Methods for preventing and cleaning up excessive pollution of coastal waters (Concept 20-4B). Question: Which two of these solutions do you think are the most important? Why?Require secondary treatment of coastal sewageRegulate coastal development, oil drilling, and oil shippingUse wetlands, solar-aquatic, or other methods to treat sewageRequire double hulls for oil tankersFig , p. 551
7520-5 How Can We Best Deal with Water Pollution? Concept Reducing water pollution requires preventing it, working with nature to treat sewage, cutting resource use and waste, reducing poverty, and slowing population growth.
76We Need to Reduce Surface Water Pollution from Nonpoint Sources (1) Reduce erosionKeep cropland covered with vegetationReduce the amount of fertilizersPlant buffer zones of vegetationUse organic farming techniques
77We Need to Reduce Surface Water Pollution from Nonpoint Sources (2) Use pesticides prudentlyControl runoffTougher pollution regulations for livestock operationsDeal better with animal waste
78Laws Can Help Reduce Water Pollution from Point Sources 1972: Clean Water ActEPA: experimenting with a discharge trading policyCould this allow pollutants to build up?
79Case Study: The U.S. Experience with Reducing Point-Source Pollution (1) Numerous improvements in water qualitySome lakes and streams are not safe for swimming or fishingTreated wastewater still produces algal bloomsHigh levels of Hg, pesticides, and other toxic materials in fish
80Case Study: The U.S. Experience with Reducing Point-Source Pollution (2) Leakage of gasoline storage tanks into groundwaterWeaken or strengthen the Clean Water Act
81Sewage Treatment Reduces Water Pollution (1) Septic tank systemWastewater or sewage treatment plantsPrimary sewage treatmentPhysical processSecondary sewage treatmentBiological processTertiary or advance sewage treatmentBleaching, chlorination
82Sewage Treatment Reduces Water Pollution (2) Should there be separate pipes for sewage and storm runoff?Health risks of swimming in water with blended sewage wastes
84(gravel or crushed stone) Manhole cover (for cleanout)Septic tankGasDistribution boxScumWastewaterSludgeDrain field(gravel or crushed stone)Figure 20.18Solutions: septic tank system used for disposal of domestic sewage and wastewater in rural and suburban areas.Vent pipePerforated pipeFig , p. 553
85Solutions: Primary and Secondary Sewage Treatment
86Sludge digester To river, lake, or ocean PrimaryGrit chamberBar screenSettling tankSecondaryChlorinedisinfection tankAeration tankSettling tankSludgeDisposed of inlandfill or ocean or applied to cropland,pasture, or rangelandRaw sewagefrom sewersSludge digesterSludge drying bed(kills bacteria)To river, lake,or oceanActivated sludgeAir pumpFigure 20.19Solutions: primary and secondary sewage treatment. Question: What do you think should be done with the sludge produced by sewage treatment plants?Stepped ArtFig , p. 554
87We Can Improve Conventional Sewage Treatment Peter Montague: environmental scientistRemove toxic wastes before water goes to the municipal sewage treatment plantsReduce or eliminate use and waste of toxic chemicalsUse composting toilet systemsWetland-based sewage treatment systems
88Science Focus: Treating Sewage by Working with Nature John Todd: biologistNatural water purification systemSewer water flows into a passive greenhouseSolar energy and natural processes remove and recycle nutrientsDiversity of organisms used
89Solutions: Ecological Wastewater Purification by a Living Machine, RI, U.S.
90There Are Sustainable Ways to Reduce and Prevent Water Pollution Developed countriesBottom-up political pressure to pass lawsDeveloping countriesLittle to reduce water pollutionChina : ambitious plan
91Solutions: Water Pollution, Methods for Preventing and Reducing Water Pollution
92What Can You Do? Water Pollution, Ways to Help Reduce Water Pollution