2Water Pollution Comes from Point and Nonpoint Sources (1) Located at specific placesEasy to identify, monitor, and regulateExamples
3Water Pollution Comes from Point and Nonpoint Sources (2) Broad, diffuse areasDifficult to identify and controlExpensive to clean upExamples
4Water 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
5Water Pollution Comes from Point and Nonpoint Sources (4) Other sources of water pollutionParking lotsHuman-made materialsE.g., plasticsClimate change due to global warming
10Common Diseases Transmitted to Humans through Contaminated Drinking Water
11Science 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
12Science Focus: Testing Water for Pollutants (2) Indicator speciesExamplesBacteria and yeast glow in the presence of a particular toxic chemicalColor and turbidity of the water
13Water 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
1420-2 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.
15Streams Can Cleanse Themselves If We Do Not Overload Them DilutionBiodegradation of wastes by bacteria takes timeOxygen sag curve
16Point 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
17Stream 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
18Global Outlook: Stream Pollution in Developing Countries Half of the world’s 500 rivers are pollutedUntreated sewageIndustrial wasteIndia’s riversChina’s rivers
19Girl Sits on the Edge of a Road beside a Stream Loaded with Raw Sewage in Iraq
20Natural Capital Degradation: Highly Polluted River in China
21Trash Truck Disposing of Garbage into a River in Peru
22Case Study: India’s Ganges River: Religion, Poverty, Population Growth, and Health (1) Holy river: religious customsSewageHuman remainsGovernment interventionWaste treatment plantsCrematoriums
23Case Study: India’s Ganges River: Religion, Poverty, Population Growth, and Health (2) Adding to the pollutionReligious customPainted statuesGlobal warmingGangotri Glacier
27Cultural Eutrophication (2) During hot weather or droughtsAlgal bloomsIncreased bacteriaMore nutrientsAnaerobic bacteriaThen what?
28Cultural Eutrophication (3) Prevent or reduce cultural eutrophicationRemove nitrates and phosphatesDiversion of lake waterClean up lakesRemove excess weedsUse herbicides and algaecides; down-side?Pump in air
29Case 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
30Case 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?
3220-3 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.
33Ground Water Cannot Cleanse Itself Very Well (1) Source of drinking waterCommon pollutantsFertilizers and pesticidesGasolineOrganic solventsPollutants dispersed in a widening plume
34Ground 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
35Hazardous 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
36Free 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
37Groundwater 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
38Case 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
39Pollution Prevention Is the Only Effective Way to Protect Groundwater Prevent contamination of groundwaterCleanup: expensive and time consuming
40SOLUTIONS 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
41There Are Many Ways to Purify Drinking Water Reservoirs and purification plantsProcess sewer water to drinking waterExpose clear plastic containers to sunlight (UV)NanofiltersThe LifeStraw
42The LifeStraw: Personal Water Purification Device
43Case Study: Protecting Watersheds Instead of Building Water Purification Plants New York City waterReservoirs in the Catskill MountainsProtect the watershed instead of water purification plants
44Using 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
45Is 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
4720-4 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.
48Ocean 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
49Ocean 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
50Industry 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
51A Large Zone of Oxygen-Depleted Water in the Gulf of Mexico Due to Algal Blooms
52Ocean 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
53Ocean 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
54Ocean Oil Pollution Is a Serious Problem (3) Faster recovery from crude oil than refined oilCleanup proceduresMethods of preventing oil spills
55SOLUTIONS 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
56We 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
57We Need to Reduce Surface Water Pollution from Nonpoint Sources (2) Use pesticides prudentlyControl runoffTougher pollution regulations for livestock operationsDeal better with animal waste
58Laws Can Help Reduce Water Pollution from Point Sources 1972: Clean Water ActEPA: experimenting with a discharge trading policyCould this allow pollutants to build up?
59Sewage Treatment Reduces Water Pollution (1) Septic tank systemWastewater or sewage treatment plantsPrimary sewage treatmentPhysical processSecondary sewage treatmentBiological processTertiary or advance sewage treatmentBleaching, chlorination
60Sewage 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
62Solutions: Primary and Secondary Sewage Treatment
63We 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
64Science 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
65Solutions: Ecological Wastewater Purification by a Living Machine, RI, U.S.
66There Are Sustainable Ways to Reduce and Prevent Water Pollution Developed countriesBottom-up political pressure to pass lawsDeveloping countriesLittle to reduce water pollutionChina : ambitious plan
67What Can You Do? Water Pollution, Ways to Help Reduce Water Pollution