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Water Pollution.

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Presentation on theme: "Water Pollution."— Presentation transcript:

1 Water Pollution

2 The solution to pollution is dilution….?
Water, Air, Land …. The solution to pollution is dilution….?

3 Water makes us unique and gives life to Earth.

4 Key Ideas What are major types and effects of water pollution?
How do we measure water quality? Point versus Nonpoint sources What 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 diseases 1.9 million from diarrhea U.S. 1.5 million illnesses 1993 Milwaukee 370,000 sick

7 What is water pollution?
Infectious Agents: bacteria and viruses often from animal wastes Oxygen 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 cleaners Plant Nutrients: water soluble nitrates, ammonia and phosphates often from sewage, agriculture and urban fertilizers Sediment: soils and silts from land erosion can disrupt photosynthesis, destroy spawning grounds, clog rivers and streams Heat Pollution and Radioactivity: mostly from powerplants

9 How do we measure water quality
Bacterial Counts: Fecal coliform counts from intestines of animals None per 100 ml for drinking >200 per 100 ml for swimming Sources: 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 decomposers Chemical Analysis: looking for presence of inorganic or organic chemicals Suspended Sediment: water clarity Indicator Species: organisms that give an idea of the health of the water body

11 Point and Nonpoint Sources
Urban streets Suburban development Wastewater treatment plant Rural homes Cropland Factory Animal feedlot POINT SOURCES

12 Major Sources of Water Pollution
Agriculture: by far the leader Sediment, fertilizers, bacteria from livestock, food processing, salt from soil irrigation Industrial: factories and powerplants Mining: surface mining toxics, acids, sediment

13 Key questions… Freshwater pollution: What are major problems in streams? Developed versus Developing Countries Lake 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 process Does not work if overloaded or stream flow reduced Does not work against non biodegradable pollutants

15 What factors will influence this oxygen sag curve?
Pollution of Streams Oxygen sag curve Factors influencing recovery What 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 growth Nonpoint still a problem Toxic chemicals still problem Success Cuyahoga River, Thames River

17 Two Worlds Developing Countries: Serious and growing problem
Half of world’s 500 major rivers heavily polluted Sewage treatment minimal $$$ Law enforcement difficult 10% of sewage in China treated Economic growth with little $$$ to clean up

18 India’s Ganges River Holy River (1 million take daily holy dip)
350 million (1/3rd of pop) live in watershed Little sewage treatment Used for bathing, drinking etc. Bodies (cremated or not) thrown in river Good news is the Indian government is beginning to work on problem

19 Freshwater Lake Pollution
Dilution as a solution in lakes less effective Little vertical mixing Little water flow (flushing) Makes them more vulnerable Toxins settle Kill bottom life Atmospheric deposition Food 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 blooms Decrease of photosynthesis Dying algae then drops DO levels Fish kills, bad odor

22 Eutrophication

23 Eutrophication in Lakes
Solutions: Advanced sewage treatment (N, P) Household detergents Soil conservation Remove excess weed build up Pump in oxygen or freshwater

24 Case Study: The Great Lakes
Pollution levels dropped, but long way to go 95% of U.S. freshwater 30% Canadian pop, 14% U.S. 38 million drink 1% flow out St. Lawrence Toxic fish


26 Groundwater Why is groundwater pollution a serious problem?
What is the extent of the problem? What are the solutions?


28 Groundwater Groundwater can become contaminated
No way to cleanse itself Little dilution and dispersion Out of sight pollution Prime source for irrigation and drinking REMOVAL of pollutant difficult

29 Groundwater Pollution: Causes
Low flow rates Few bacteria Low oxygen Cold temperatures Hazardous waste injection well Pesticides Coal strip mine runoff De-icing road salt Buried gasoline and solvent tank Pumping well Cesspool septic tank Gasoline station Waste lagoon Water pumping well Sewer Landfill Leakage from faulty casing Accidental spills Discharge Unconfined freshwater aquifer Confined aquifer Confined freshwater aquifer Groundwater flow


31 Prevention is the most effective and cheapest

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 Pollution Oceans can disperse and break down large quantities of degradable pollution if they are not overloaded. Pollution worst near heavily populated coastal zones Wetlands, estuaries, coral reefs, mangrove swamps 40% of world’s pop. Live within 62 miles of coast

34 Mangrove Swamp

35 Estuaries

36 Ocean Pollution Large amounts of untreated raw sewage (viruses)
Leaking septic tanks Runoff Algae blooms from nutrients Dead zones NO DO Airborne toxins Oil spills

37 Ocean Pollution


39 Case Study: Chesapeake Bay
Largest US estuary Relatively shallow Slow “flushing” action to Atlantic Major 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 Spills Sources: offshore wells, tankers, pipelines and storage tanks Effects: death of organisms, loss of animal insulation and buoyancy, smothering Significant economic impacts Mechanical cleanup methods: skimmers and blotters Chemical cleanup methods: coagulants and dispersing agents

42 Oil Spills



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

46 Nonpoint Sources Reduce runoff

47 Nonpoint Sources Buffer Zones Near Streams

48 Nonpoint Prevent soil erosion and only apply needed pesticides and fertilizers

49 Point Sources Most 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 discharge Requires sewage treatment Require permits for wetland destruction Does not deal with nonpoint sources well Goal All Waterways fishable and swimable

51 Technological Approach: Septic Systems
Require suitable soils and maintenance ¼ of all U.S. homes have Septic tanks Can 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 overflows EPA: $100 billion to fix

53 Technological Approach: Sewage Treatment
Physical and biological treatment Fig 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 biodegradables Tertiary: advanced techniques only used in 5% of U.S. $$$$ Disinfection: chlorine, ozone, UV What is not taken out???


57 Technological Approach: Advanced (Tertiary) Sewage Treatment
Uses physical and chemical processes Removes nitrate and phosphate Expensive Not widely used

58 Sludge disposal…using as fertilizer

59 Technological Approach: Using Wetlands to Treat Sewage


61 The Good News Largely thanks to CWA:
Between 1972 – 2002 fishable and swimmable streams 36% to 60% 74% served by sewage treatment Wetlands loss dropped by 80% Topsoil losses dropped by 1 billion tons annually

62 The Bad News 45% of Lakes, 40% streams still not fishable and swimmable Nonpoint sources still huge problem Livestock and Ag. Runoff Fish 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 water Protection from terrorism Purification of rural drinking water Safe Drinking Water Act Maximum contaminant levels (MCLs) Bottled water

67 Safe Drinking Water Act
54 countries have drinking water laws SDWA passed 1974 requires EPA to set drinking water standards Maximum Contaminating Levels (MCLs)

68 Safe Drinking Water Act
Privately owned wells exempt from SDWA SDWA requires public notification of failing to meet standards and fine. MCLs often stated in parts per million or parts per billion

69 Bottle Water U.S. has the world’s safest tap water due to billions of $$$ of investment Bottle water 240 to 10,000 times more expensive than tap water 25% of bottle water is tap water

70 Bottle Water 1.4 million metric tons of bottle thrown away each year
Toxic fumes released during bottling Bottles made from oil based plastics Water does not need to meet SDWA



73 This presentation was from an online power point prepared by Richard Clements for G. Tyler Miller’s Living in the Environment 14th edition.

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