1. WaterSection 3 Water Pollution Water pollution is the introduction of chemical, physical, or biological agents into water that degrade water quality. The two underlying causes of water pollution: – industrialization –rapid human population growth.

2. WaterSection 3 Point-Source Pollution Water pollution comes from two types of sources: point and nonpoint sources. Point-source pollution is pollution that comes from a specific site. (ex. factories, landfills, oil tankers

3. WaterSection 3 Nonpoint-Source Pollution Non-point source pollution is pollution that comes from many sources rather than from a single specific site. (ex. chemicals added to road surfaces, runoff)

4. WaterSection 3 Principal Water Pollutants Wastewater is water that contains wastes from homes or industry. Must be treated at a wastewater treatment plant before it is returned to a river or lake

5. WaterSection 3 Wastewater Treatment Process

6. WaterSection 3 Sewage Sludge One of the products of wastewater treatment is sewage sludge, the solid material that remains after treatment. Problems: –If contains toxic chemicals it must be disposed of as hazardous waste Very expensive due to the volume –Solutions: If toxic levels are low can be used as fertilizer Combined with clay to form bricks

7. WaterSection 3 Artificial Eutrophication Artificial eutrophication is a process that increases the amount of nutrients in a body of water through human activities, such as waste disposal and land drainage. The major causes of eutrophication are fertilizer and phosphates in some laundry detergents.

8. WaterSection 3 Artificial Eutrophication Problem: –Excess phosporus causes an increase in the growth of algae (algal blooms) –Causes a decrease of dissolved oxygen in the water which causes fish and other organisms to suffocate and die Solution: –Some states have banned products or limited the amount of phosphates in products

9. WaterSection 3 Thermal Pollution Thermal pollution is a temperature increase in a body of water that is caused by human activity. Causes: power plants and other industries use water in their cooling systems and then discharge the warm water into a lake or river.

10. WaterSection 3 Thermal Pollution Problems: kill large amounts of fish due to temperature of the water and a decrease in oxygen levels.

11. WaterSection 3 Groundwater Pollution Pollutants usually enter groundwater when polluted surface water percolates down from the Earth’s surface. (ex. pesticides, herbicides, fertilizers)

12. WaterSection 3 Groundwater Pollution

13. WaterSection 3 Cleaning Up Groundwater Pollution Groundwater pollution is one of the most challenging environmental problems in the world. Takes hundreds of years for aquifers to recycle and purge contaminants.

14. WaterSection 3 Ocean Pollution At least 85 percent of ocean pollution, including pollutants such as oil, toxic wastes, and medical wastes, comes from activities on land, near the coasts.

15. WaterSection 3 Oil Spills Ocean water is also polluted by accidental oil spills. Each year, about 37 million gallons of oil from tanker accidents are spilled into the ocean. –Most of the oil that pollutes oceans comes from cities and towns

16. WaterSection 3

17. WaterSection 3 Water Pollution and Ecosystems Biomagnification is the accumulation of pollutants at successive levels of the food chain. Biomagnification has alarming consequences for organisms at the top of the food chain, and is one reason why U.S. states limit the amount of fish people can eat from certain bodies of water.

18. WaterSection 3 Water Pollution and Ecosystems

19. WaterSection 3 Federal Laws Addressing Water Quality 1972 Clean Water Act(1972).Making water fit for swimming and fishing 1975 Safe Water Drinking Act – protect groundwater and surface water from pollution 1987 Water quality Act – Clean polluted runoff 1990-Oil Pollution Act- Attempts to protect US waterways from oil pollution