1. Water Pollution Chapter 20

2. Case Study: A River on Fire  Cuyahoga River  Cleveland, Ohio (1969)  Spurred major Amendments to Clean Water Act

3. Water Pollution Comes from Point and Nonpoint Sources  Water pollution is any chemical, biological, or physical change in water quality that harms living organisms or makes water unsuitable for desired uses.  Underlying causes are industrialization and rapid human population growth.

4. Point Source Pollution  Point-source pollution is pollution that comes from a specific site.  Examples:

5. Point Source Pollution

6. Point Source of Polluted Water in Gargas, France

7. Nonpoint Source Pollution  Non-point source pollution is pollution that comes from many sources rather than from a single specific site.  Example:

8. Nonpoint Source Pollution

9. Nonpoint Sediment from Unprotected Farmland Flows into Streams

10. Water Pollution Comes from Point and Nonpoint Sources  Agriculture activities: leading cause of water pollution  Industrial facilities  Mining

11. Water Pollution Comes from Point and Nonpoint Sources  Other sources of water pollution Parking lots Human-made materials E.g., plastics

13. Major Water Pollutants Have Harmful Effects  Infectious disease organisms: contaminated drinking water  The World Health Organization (WHO) 3 Million people die every year, mostly under the age of 5

14. Major Water Pollutants and Their Sources

15. Common Diseases Transmitted to Humans through Contaminated Drinking Water

16. 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 determines presence of organic chemicals

17. DO Seasonal Variation: DO & Temp Inverse Relationship

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

21. Secchi Disk

24. Water Quality as Measured by Dissolved Oxygen Content in Parts per Million

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

26. Dilution and Decay of Degradable, Oxygen-Demanding Wastes in a Stream

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

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

29. Girl Sits on the Edge of a Road beside a Stream Loaded with Raw Sewage in Iraq

30. Natural Capital Degradation: Highly Polluted River in China

31. Trash Truck Disposing of Garbage into a River in Peru

32. Case Study: India’s Ganges River: Religion, Poverty, Population Growth, and Health (1)  Holy river: religious customs  Sewage  Human remains  Government intervention

33. Low Water Flow and Too Little Mixing Makes Lakes Vulnerable to Water Pollution  More vulnerable than streams  Less effective at diluting pollutants than streams

34. Cultural Eutrophication Is Too Much of a Good Thing (1)  Eutrophication – nutrient enrichment  Oligotrophic lake  Cultural eutrophication

35. Natural Eutrophication

36. Algae/Cyanobacteria

37. Duckweed

38. Water Hyacinth – Invasive Species

39. The Great Lakes of North America

40. Round Goby