4 Key Ideas What are major types and effects of water pollution? How do we measure water quality?Point versus Nonpoint sourcesWhat are the major sources of pollution?
5 What is water pollution? Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired usage.
6 What is water pollution? WHO:3.4 million premature deaths each year from waterborne diseases1.9 million from diarrheaU.S. 1.5 million illnesses1993 Milwaukee 370,000 sick
7 What is water pollution? Infectious Agents: bacteria and viruses often from animal wastesOxygen Demanding Wastes: organic waste that needs oxygen often from animal waste, paper mills and food processing.Inorganic Chemicals: Acids and toxic chemicals often from runoff, industries and household cleaners
8 What is water pollution? Organic Chemicals: oil, gasoline, plastics, detergents often from surface runoff, industries and cleanersPlant Nutrients: water soluble nitrates, ammonia and phosphates often from sewage, agriculture and urban fertilizersSediment: soils and silts from land erosion can disrupt photosynthesis, destroy spawning grounds, clog rivers and streamsHeat Pollution and Radioactivity: mostly from powerplants
9 How do we measure water quality Bacterial Counts: Fecal coliform counts from intestines of animalsNone per 100 ml for drinking>200 per 100 ml for swimmingSources: human sewage, animals, birds, raccoons, etc.
10 How do we measure water quality Dissolved Oxygen: BOD Biological Oxygen Demand…the amount of oxygen consumed by aquatic decomposersChemical Analysis: looking for presence of inorganic or organic chemicalsSuspended Sediment: water clarityIndicator Species: organisms that give an idea of the health of the water body
11 Point and Nonpoint Sources Urban streetsSuburban developmentWastewater treatment plantRural homesCroplandFactoryAnimal feedlotPOINT SOURCES
12 Major Sources of Water Pollution Agriculture: by far the leaderSediment, fertilizers, bacteria from livestock, food processing, salt from soil irrigationIndustrial: factories and powerplantsMining: surface mining toxics, acids, sediment
13 Key questions…Freshwater pollution: What are major problems in streams?Developed versus Developing CountriesLake Pollution: Why are lakes and reservoirs more vulnerable?What is Eutrophication?
14 Freshwater Stream Pollution Flowing streams can recover from moderate level of degradable water pollution if their flows are not reduced.Natural biodegradation processDoes not work if overloaded or stream flow reducedDoes not work against non biodegradable pollutants
15 What factors will influence this oxygen sag curve? Pollution of StreamsOxygen sag curveFactors influencing recoveryWhat factors will influence this oxygen sag curve?
16 Two Worlds Developed Countries U.S. and other developed countries sharply reduced point sources even with population and economic growthNonpoint still a problemToxic chemicals still problemSuccess Cuyahoga River, Thames River
17 Two Worlds Developing Countries: Serious and growing problem Half of world’s 500 major rivers heavily pollutedSewage treatment minimal $$$Law enforcement difficult10% of sewage in China treatedEconomic growth with little $$$ to clean up
18 India’s Ganges River Holy River (1 million take daily holy dip) 350 million (1/3rd of pop) live in watershedLittle sewage treatmentUsed for bathing, drinking etc.Bodies (cremated or not) thrown in riverGood news is the Indian government is beginning to work on problem
19 Freshwater Lake Pollution Dilution as a solution in lakes less effectiveLittle vertical mixingLittle water flow (flushing)Makes them more vulnerableToxins settleKill bottom lifeAtmospheric depositionFood chain disruptions
20 Biomagnifications of PCBs in an aquatic food chain from the Great Lakes.
21 Eutrophication of Lakes Eutrophication: nutrient enrichment of lakes mostly from runoff of plant nutrients (nitrates and phosphates)During hot dry weather can lead to algae bloomsDecrease of photosynthesisDying algae then drops DO levelsFish kills, bad odor
32 Ocean Pollution How much pollution can the oceans tolerate? Coastal zones: How does pollution affect coastal zones?What are major sources of ocean pollution and what is being done?Oils spills
33 Ocean PollutionOceans can disperse and break down large quantities of degradable pollution if they are not overloaded.Pollution worst near heavily populated coastal zonesWetlands, estuaries, coral reefs, mangrove swamps40% of world’s pop. Live within 62 miles of coast
39 Case Study: Chesapeake Bay Largest US estuaryRelatively shallowSlow “flushing” action to AtlanticMajor problems with dissolved O2
40 Preventing and reducing the flow of pollution from land and from streams emptying into the ocean is key to protecting oceans
41 Oil SpillsSources: offshore wells, tankers, pipelines and storage tanksEffects: death of organisms, loss of animal insulation and buoyancy, smotheringSignificant economic impactsMechanical cleanup methods: skimmers and blottersChemical cleanup methods: coagulants and dispersing agents
45 Prevention and Reduction How can we reduce surface water pollution: point and also nonpoint.How do sewage treatment plants work?How successful has the U.S. been at reducing water pollution? Clean Water Act
48 NonpointPrevent soil erosion and only apply needed pesticides and fertilizers
49 Point SourcesMost developed countries use laws to set water pollution standards.Federal Water Pollution Control Act (Clean Water Act 1972, ’77, ’87)Regulates navigable waterways, streams, wetlands, rivers, lake
50 Clean Water Act Sets standards for key pollutants Requires permits for dischargeRequires sewage treatmentRequire permits for wetland destructionDoes not deal with nonpoint sources wellGoal All Waterways fishable and swimable
51 Technological Approach: Septic Systems Require suitable soils and maintenance¼ of all U.S. homes have Septic tanksCan be used in parking lots, business parks, etc.
52 Combined sewer overflow is a problem in many older towns EPA: 1.8 M to 3.85 M sick from swimming in water contaminated by sewer overflowsEPA: $100 billion to fix
53 Technological Approach: Sewage Treatment Physical and biological treatmentFig p. 511
55 Primary: removes 60% of solids and 30-40% oxygen demanding wastes (physically) Secondary: uses biological processes to remove up to 90% of biodegradablesTertiary: advanced techniques only used in 5% of U.S. $$$$Disinfection: chlorine, ozone, UVWhat is not taken out???
61 The Good News Largely thanks to CWA: Between 1972 – 2002 fishable and swimmable streams 36% to 60%74% served by sewage treatmentWetlands loss dropped by 80%Topsoil losses dropped by 1 billion tons annually
62 The Bad News45% of Lakes, 40% streams still not fishable and swimmableNonpoint sources still huge problemLivestock and Ag. RunoffFish with toxins
65 Drinking Water How is drinking water purified? High tech way. How can we purify drinking water in developing nations?What is the Safe Drinking Water Act?Is bottled water a good answer or an expensive rip-off?
66 Drinking Water Quality Purification of urban drinking waterProtection from terrorismPurification of rural drinking waterSafe Drinking Water ActMaximum contaminant levels (MCLs)Bottled water
67 Safe Drinking Water Act 54 countries have drinking water lawsSDWA passed 1974 requires EPA to set drinking water standardsMaximum Contaminating Levels (MCLs)
68 Safe Drinking Water Act Privately owned wells exempt from SDWASDWA requires public notification of failing to meet standards and fine.MCLs often stated in parts per million or parts per billion
69 Bottle WaterU.S. has the world’s safest tap water due to billions of $$$ of investmentBottle water 240 to 10,000 times more expensive than tap water25% of bottle water is tap water
70 Bottle Water 1.4 million metric tons of bottle thrown away each year Toxic fumes released during bottlingBottles made from oil based plasticsWater does not need to meet SDWA