1. Chapter 20 Water Pollution

2. The Seattle, Washington Area, U.S.
Figure 20.1: The U.S. city of Seattle, Washington, was founded on the shore of Puget Sound and quickly expanded eastward toward Lake Washington.
Fig. 20-1, p. 528

3. Core Case Study: Lake Washington
Sewage dumped into Lake Washington
1955: Edmondson discovered cyanobacteria in the lake
Role of phosphorus
Public pressure led to cleanup of the lake
Sewage treatment plant effluent to Puget Sound
New pollution challenges

4. Water Pollution Comes from Point and Nonpoint Sources (1)
Change in water quality that can harm organisms or make water unfit for human uses
Contamination with chemicals
Excessive heat
Point sources
Located at specific places
Easy to identify, monitor, and regulate
Examples

5. Water Pollution Comes from Point and Nonpoint Sources (2)
Broad, diffuse areas
Difficult to identify and control
Expensive to clean up
Examples

6. Water Pollution Comes from Point and Nonpoint Sources (3)
Leading causes of water pollution
Agriculture activities
Sediment eroded from the lands
Fertilizers and pesticides
Bacteria from livestock and food processing wastes
Industrial facilities
Mining

7. Nonpoint Sediment from Unprotected Farmland Flows into Streams
Figure 20.4: Nonpoint sediment pollution eroded from farmland flows into streams and sometimes changes their courses or dams them up. As measured by weight, it is the largest source of water pollution. Question: What do you think the owner of this farm could have done to prevent such sediment pollution?
Fig. 20-4, p. 530

8. Plastic Wastes in Mountain Lake
Figure 20.6: Plastics and other forms of waste pollute this mountain lake as well as many bodies of water around the world, and can release harmful chemicals into the water.
Fig. 20-6, p. 531

9. Major Water Pollutants Have Harmful Effects
Infectious disease organisms: contaminated drinking water
The World Health Organization (WHO)
1.6 million people die every year, mostly under the age of 5

10. Major Water Pollutants and Their Sources
Table 20-1
Table 20-1, p. 532

11. Common Diseases Transmitted to Humans through Contaminated Drinking Water
Table 20-2
Table 20-2, p. 532

12. Science Focus: Testing Water for Pollutants (1)
Variety of tests to determine water quality
Coliform bacteria: Escherichia coli, significant levels
Level of dissolved oxygen (DO)
Chemical analysis

13. Science Focus: Testing Water for Pollutants (2)
Indicator species
Examples
Bacteria and yeast glow in the presence of a particular toxic chemical
Color and turbidity of the water

14. Water Quality as Measured by Dissolved Oxygen Content in Parts per Million
Figure 20.A: Scientists measure dissolved oxygen (DO) content in parts per million (ppm) at 20°C (68°F) as an indicator of water quality. Only a few fish species can survive in water with less than 4 ppm of dissolved oxygen at this temperature. Some warm-water species have evolved ways to tolerate low DO levels better than most 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.
Fig. 20-A, p. 533

15. Streams Can Cleanse Themselves If We Do Not Overload Them
Dilution
Biodegradation of wastes by bacteria takes time
Oxygen sag curve

16. Dilution and Decay of Degradable, Oxygen-Demanding Wastes in a Stream
Figure 20.7: Natural capital.
A stream can dilute and decay degradable, oxygen-demanding wastes, and it can also dilute heated water. This figure shows 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 the 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 discharge pipe emitting biodegradable waste to the right of the one in this picture?
Fig. 20-7, p. 534

17. Stream Pollution in More Developed Countries
1970s: Water pollution control laws
Successful water clean-up stories
Ohio Cuyahoga River, U.S.
Thames River, Great Britain
Contamination of toxic inorganic and organic chemicals by industries and mines

18. Global Outlook: Stream Pollution in Developing Countries
Half of the world’s 500 major rivers are polluted
Untreated sewage
Industrial waste
India’s rivers
China’s rivers

19. Too Little Mixing and Low Water Flow Makes Lakes Vulnerable to Water Pollution
Less effective at diluting pollutants than streams
Stratified layers
Little vertical mixing
Little of no water flow
Can take up to 100 years to change the water in a lake
Biological magnification of pollutants

20. Cultural Eutrophication Is Too Much of a Good Thing (1)
Natural enrichment of a shallow lake, estuary, or slow-moving stream
Caused by runoff into lake that contains nitrates and phosphates
Oligotrophic lake
Low nutrients, clear water

21. Cultural Eutrophication Is Too Much of a Good Thing (2)
Nitrates and phosphates from human sources
Farms, feedlots, streets, parking lots
Fertilized lawns, mining sites, sewage plants
During hot weather or droughts
Algal blooms
Increased bacteria
More nutrients
Anaerobic bacteria

22. Cultural Eutrophication Is Too Much of a Good Thing (3)
Prevent or reduce cultural eutrophication
Remove nitrates and phosphates
Diversion of lake water
Clean up lakes
Remove excess weeds
Use herbicides and algaecides; down-side?
Pump in air

23. Cultural Eutrophication of Chinese Lake
Figure 20.11: Global outlook: Severe cultural eutrophication has covered this lake near the Chinese city of Haozhou with algae.
Fig , p. 537

24. Revisiting Lake Washington and Puget Sound
Severe water pollution can be reversed
Citizen action combined with scientific research
Good solutions may not work forever
Wastewater treatment plant effluents sent into Puget Sound
Now what’s happening?

25. Case Study: Pollution in the Great Lakes (1)
1960s: Many areas with cultural eutrophication
1972: Canada and the United States: Great Lakes pollution control program
Decreased algal blooms
Increased dissolved oxygen
Increased fishing catches
Swimming beaches reopened
Better sewage treatment plants
Fewer industrial wastes
Bans on phosphate-containing household products

26. Case Study: Pollution in the Great Lakes (2)
Problems still exist
Raw sewage
Nonpoint runoff of pesticides and fertilizers
Biological pollution
Atmospheric deposition of pesticides and Hg

27. Case Study: Pollution in the Great Lakes (3)
2007 State of the Great Lakes report
New pollutants found
Wetland loss and degradation
Declining of some native species
Native carnivorous fish species declining
What should be done?

28. The Great Lakes of North America
Figure 20.12: The five Great Lakes of North America make up the world’s largest freshwater system. Dozens of major cities in the United States and Canada are located on their shores, and water pollution in the lakes is a growing problem.
Fig , p. 538

29. Ground Water Cannot Cleanse Itself Very Well (1)
Source of drinking water
Common pollutants
Fertilizers and pesticides
Gasoline
Organic solvents
Pollutants dispersed in a widening plume

30. Ground Water Cannot Cleanse Itself Very Well (2)
Slower chemical reactions in groundwater due to
Slow flow: contaminants not diluted
Less dissolved oxygen
Fewer decomposing bacteria
Low temperatures

31. Principal Sources of Groundwater Contamination in the U.S.
Figure 20.13: Natural capital degradation.
These are the principal sources of groundwater contamination in the United States (Concept 20-3a). Another source in coastal areas is saltwater intrusion from excessive groundwater withdrawal. (Figure is not drawn to scale.) Question: What are three sources shown in this picture that might be affecting groundwater in your area?
Fig , p. 540

32. Groundwater Pollution Is a Serious Hidden Threat in Some Areas
China: 90% of urban aquifers are contaminated or overexploited
U.S.: FDA reports of toxins found in many aquifers
Threats
Gasoline, oil
Nitrate ions
Arsenic

33. Pollution Prevention Is the Only Effective Way to Protect Groundwater
Prevent contamination of groundwater
Cleanup: expensive and time consuming

34. Groundwater Pollution
Solutions
Groundwater Pollution
Prevention
Cleanup
Find substitutes for toxic chemicals
Pump to surface, clean, and return to aquifer (very expensive)
Keep toxic chemicals out of the environment
Install monitoring wells near landfills and underground tanks
Inject microorganisms to clean up contamination (less expensive but still costly)
Require leak detectors on underground tanks
Ban hazardous waste disposal in landfills and injection wells
Figure 20.14: There are ways to prevent and ways to clean up contamination of groundwater but prevention is the only effective approach (Concept 20-3B). Questions: Which two of these preventive solutions do you think are the most important? Why?
Store harmful liquids in aboveground tanks with leak detection and collection systems
Pump nanoparticles of inorganic compounds to remove pollutants (still being developed)
Fig , p. 541

35. There Are Many Ways to Purify Drinking Water
Reservoirs and purification plants
Process sewer water to drinking water
Expose clear plastic containers to sunlight (UV)
The LifeStraw
PUR: chlorine and iron sulfate powder

36. The LifeStraw: Personal Water Purification Device
Figure 20.15: The LifeStraw™, designed by Torben Vestergaard Frandsen, is a personal water purification device that gives many poor people access to safe drinking water. Here, four young men in Uganda demonstrate its use. Question: Do you think the development of such devices should make prevention of water pollution less of a priority? Explain.
Fig , p. 542

37. Case Study: Protecting Watersheds Instead of Building Water Purification Plants
New York City water
Reservoirs in the Catskill Mountains
Paid towns, farmers, and others in the watershed to restore forests, wetlands, and streams
Saved the cost of building a plant: $6 billion

38. Using Laws to Protect Drinking Water Quality
1974: U.S. Safe Drinking Water Act
Sets maximum contaminant levels for any pollutants that affect human health
Health scientists: strengthen the law
Water-polluting companies: weaken the law

39. Case Study: Is Bottled Water the Answer?
U.S.: some of the cleanest drinking water
Bottled water
Some from tap water
40% bacterial contamination
Fuel cost to manufacture the plastic bottles
Recycling of the plastic
240-10,000x the cost of tap water
Growing back-to-the-tap movement

40. Ocean Pollution Is a Growing and Poorly Understood Problem (1)
2006: State of the Marine Environment
80% of marine pollution originates on land
Sewage
Coastal areas most affected
Deeper ocean waters
Dilution
Dispersion
Degradation

41. Ocean Pollution Is a Growing and Poorly Understood Problem (2)
Cruise line pollution: what is being dumped?
U.S. coastal waters
Raw sewage
Sewage and agricultural runoff: NO3- and PO43-
Harmful algal blooms
Oxygen-depleted zones
Huge mass of plastic in North Pacific Ocean

42. Residential Areas, Factories, and Farms Contribute to Pollution of Coastal Waters
Figure 20.16: Natural capital degradation.
Residential areas, factories, and farms all contribute to the pollution of coastal waters. According to the UN Environment Programme, coastal water pollution costs the world more than $30,000 a minute, primarily for health problems and premature deaths. Questions: What do you think are the three worst pollution problems shown here? For each one, how does it affect two or more of the ecological and economic services listed in Figure 8-5 (p. 172)?
Fig , p. 545

43. Science Focus: Oxygen Depletion in the Northern Gulf Of Mexico
Severe cultural eutrophication
Oxygen-depleted zone
Overfertilized coastal area
Preventive measures
Will it reach a tipping point?

44. A Large Zone of Oxygen-Depleted Water in the Gulf of Mexico Due to Algal Blooms
Figure 20.B: Natural capital degradation.
A large zone of oxygen-depleted water (containing less than 2 ppm dissolved oxygen) forms each year in the Gulf of Mexico (lower right drawing) as a result of oxygen-depleting algal blooms caused primarily by high inputs of plant nutrients from the Mississippi River basin (top). The drawing (bottom left), based on a satellite image, shows how these inputs spread along the coast during the summer of In the image, reds and greens represent high concentrations of phytoplankton and river sediment. This problem is worsened by loss of wetlands, which would have filtered some of these plant nutrients. Question: Can you think of a product you used today that was directly connected to this sort of pollution? (Data from NASA)
Fig. 20-B, p. 546

45. Ocean Pollution from Oil (1)
Crude and refined petroleum
Highly disruptive pollutants
Largest source of ocean oil pollution
Urban and industrial runoff from land
1989: Exxon Valdez, oil tanker
2010: BP explosion in the Gulf of Mexico

46. Ocean Pollution from Oil (2)
Volatile organic hydrocarbons
Kill many aquatic organisms
Tar-like globs on the ocean’s surface
Coat animals
Heavy oil components sink
Affect the bottom dwellers

47. Ocean Pollution from Oil (3)
Faster recovery from crude oil than refined oil
Cleanup procedures
Methods of preventing oil spills

48. Coastal Water Pollution
Solutions
Coastal Water Pollution
Prevention
Cleanup
Reduce input of toxic pollutants
Improve oil-spill cleanup capabilities
Separate sewage and storm water lines
Use 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 waters
Ban dumping of hazardous material
Figure 20.17: There are a number of methods for preventing or cleaning up excessive pollution of coastal waters (Concept 20-4B). Questions: Which two of these solutions do you think are the most important? Why?
Require secondary treatment of coastal sewage
Strictly regulate coastal development, oil drilling, and oil shipping
Use wetlands, solar-aquatic, or other methods to treat sewage
Require double hulls for oil tankers
Fig , p. 547

49. Deepwater Horizon Blowout in the Gulf of Mexico, April 20, 2010
Figure 20.18: On April 20, 2010 oil and natural gas escaping from an oil-well borehole ignited and caused an explosion on the British Petroleum (BP) Deepwater Horizon drilling platform in the Gulf of Mexico. The accident sank the rig and killed 11 of its crewmembers. The ruptured wellhead released massive amounts of crude oil that contaminated ecologically vital coastal marshes (Figure 8-8, p. 174), mangroves (Figure 8-10, p. 175), sea-grass beds (Figure 8-9, p. 174) and deep ocean aquatic life. It also disrupted the livelihoods of people depending on the gulf’s coastal fisheries and caused large economic losses for the gulf’s tourism business. This disaster was caused by a combination of equipment failure, human error, failure by BP to prepare for a major oil release, and inadequate government regulation of oil drilling in the Gulf of Mexico.
Fig , p. 547

50. Case Study: The Exxon Valdez Oil Spill
1989: Alaska’s Prince William Sound
41 million liters of crude oil
5200 km of coastline
Killed 250,000 seabirds
$15 billion in damages to economy
Exxon paid $3.8 billion in damages and clean-up costs
Led to improvements in oil tanker safety and clean-up strategies

51. Reducing Surface Water Pollution from Nonpoint Sources
Agriculture
Reduce erosion
Reduce the amount of fertilizers
Plant buffer zones of vegetation
Use organic farming techniques
Use pesticides prudently
Control runoff
Tougher pollution regulations for livestock operations
Deal better with animal waste

52. Laws Can Help Reduce Water Pollution from Point Sources
1972: Clean Water Act 1987: Water Quality Act
EPA: experimenting with a discharge trading policy that uses market forces
Cap and trade system
Could this allow pollutants to build up?

53. Case Study: The U.S. Experience with Reducing Point-Source Pollution (1)
Numerous improvements in water quality
Some lakes and streams are not safe for swimming or fishing
Treated wastewater still produces algal blooms
High levels of Hg, pesticides, and other toxic materials in fish

54. Case Study: The U.S. Experience with Reducing Point-Source Pollution (2)
Leakage of gasoline storage tanks into groundwater
Many violations of federal laws and regulations
Need to strengthen the Clean Water Act

55. Sewage Treatment Reduces Water Pollution (1)
Septic tank system
Wastewater or sewage treatment plants
Primary sewage treatment
Physical process
Secondary sewage treatment
Biological process with bacteria
Tertiary or advance sewage treatment
Special filtering processes
Bleaching, chlorination

56. Sewage Treatment Reduces Water Pollution (2)
Many cities violate federal standards for sewage treatment plants
Should there be separate pipes for sewage and storm runoff?
Health risks of swimming in water with blended sewage wastes

57. Solutions: Septic Tank System
Figure 20.19: Solutions.
Septic tank systems are often used for disposal of domestic sewage and wastewater in rural and suburban areas.
Fig , p. 550

58. Solutions: Primary and Secondary Sewage Treatment
Figure 20.20: Solutions.
Primary and secondary sewage treatment systems help to reduce water pollution. Question: What do you think should be done with the sludge produced by sewage treatment plants?
Fig , p. 551

59. We Can Improve Conventional Sewage Treatment
Peter Montague: environmental scientist
Remove toxic wastes before water goes to the municipal sewage treatment plants
Reduce or eliminate use and waste of toxic chemicals
Use composting toilet systems
Wetland-based sewage treatment systems

60. Science Focus: Treating Sewage by Working with Nature
John Todd: biologist
Natural water purification system
Sewer water flows into a passive greenhouse
Solar energy and natural processes remove and recycle nutrients
Diversity of organisms used

61. Solutions: Ecological Wastewater Purification by a Living Machine, RI, U.S.
Figure 20.C: Solutions.
This is an ecological wastewater purification system called a living machine. This Solar Sewage Treatment Plant is in the U.S. city of Providence, Rhode Island. Biologist John Todd is demonstrating this ecological process he invented for purifying wastewater by using the sun and a series of tanks containing living organisms. Todd and others are conducting research to perfect such solar–aquatic sewage treatment systems based on working with nature.
Fig. 20-C, p. 553

62. There Are Sustainable Ways to Reduce and Prevent Water Pollution
Developed countries
Bottom-up political pressure to pass laws
Developing countries
Little has been done to reduce water pollution
China : ambitious plan

63. Solutions: Methods for Preventing and Reducing Water Pollution
Figure 20.21: There are a number of ways to prevent and reduce water pollution (Concept 20-5). Questions: Which two of these solutions do you think are the most important? Why?
Fig , p. 553

64. What Can You Do? Reducing Water Pollution
Figure 20.22: Individuals matter.
You can help reduce water pollution. Questions: Which three of these actions do you think are the most important? Why?
Fig , p. 554

65. Three Big Ideas
There are a number of ways to purify drinking water, but the most effective and cheapest strategy is pollution control.
The key to protecting the oceans is to reduce the flow of pollution from land and air, and from streams emptying into ocean waters.

66. Three Big Ideas
Reducing water pollution requires that we prevent it, work with nature in treating sewage, cut resource use and waste, reduce poverty, and slow population growth.