1. Chapter 21: Water Pollution
Sustainably Managing a Renewable Resource

2. FIGURE CO: Water pollution in rich and poor countries of the world affects our health and economy
© Rubberball/Alamy Images

3. Point and Nonpoint Sources
Point sources, such as factories, and from Nonpoint sources, such as farm fields and streets.
Courtesy of U.S. Environmental Protection Agency, Great Lakes National Program

4. FIGURE 2: Major sources of U.S. stream pollution

5. FIGURE 3: Sources of nonpoint water pollution affecting streams

6. FIGURE 5: The oxygen sag curve

7. FIGURE 6: Eutrophication and succession

8. Fecal coliform bacteria
Infectious Agents
FIGURE 7: Cryptosporidium, an infectious waterborne protist that can cause diarrhea in humans
FIGURE 8:
Fecal coliform bacteria
© A. B. Dowsett/Photo Researchers, Inc.

9. Toxic Organic Water Pollutants
Organics
Sources: factories, homes, farms, lawns, and gardens.
Inorganic (acids and heavy metals, such as lead and mercury)
Sources: Industry

10. Other Types of Pollution: Sediment
Sediment washed from the land has profound effects on the chemical and physical nature of ecosystems.
Such changes have large impacts on aquatic organisms and humans who depend on them.

11. FIGURE 9: Thermal pollution

12. 21.2 Groundwater Pollution
May be heavily contaminated in numerous industrialized nations by:
industrial waste pits
septic tanks
oil wells
Landfills
agricultural chemicals, notably pesticides and fertilizer.

13. Effects of Groundwater Pollution
Thousands of chemicals may be found in a nation’s groundwater.
Many of them are potentially harmful to human health, causing problems for:
unborn children:
miscarriage
birth defects
premature infant death
adults:
rashes
neurological problems

14. Cleaning Up Groundwater
Groundwater moves slowly and takes many years to cleanse itself.
Preventing groundwater pollution is essential to creating a sustainable water supply.
Equally important are efforts to clean up groundwater supplies already contaminated by potentially toxic chemicals.

15. 21.3 Ocean Pollution The oceans are polluted by: chemicals spilled
into them directly
pollutants washed
from the lands and
transported to
them by rivers
FIGURE 10:
An oil-covered duck
Courtesy of John S. Lough/Exxon Valdez Oil Spill Trustee Council

16. FIGURE 12: Oil spills from 1970 to 2006
Data courtesy of International Tanker Owners Pollution Federation Ltd., ITOPF

17. A young hawksbill sea turtle is caught in a plastic fishing net
Plastic Pollution
Millions of tons of plastic are dumped into the ocean each year, killing hundreds of thousands of marine
mammals, fish,
and birds.
FIGURE 13:
A young hawksbill sea turtle is caught in a plastic fishing net
© Jeff Rotman/Alamy Images

18. Trash on Imperial Beach, California
Plastic Pollution
Many steps have been taken to reduce the disposal of plastic into the ocean, but huge amounts are still being disposed of each year.
FIGURE 14:
Trash on Imperial Beach, California
© T. O’Keefe/PhotoLink/Photodisc/Getty Images

19. Medical Wastes and Sewage Sludge
Millions of gallons of sewage enter the sea each year from coastal sewage treatment plants.
FIGURE 15: Sewage treatment plant
© Graham Prentice/Dreamstime.com

20. FIGURE S01_1: Algal blooms in the Great Lakes
© John Sohlden/Visuals Unlimited

21. 21.4 Water Pollution Control
Reducing water pollution requires efforts on two levels:
those that capture wastes emitted from various sources (the so-called end-of-pipe solutions)
those that prevent waste production and pollution

22. Legislative Controls
Legislation to address water pollution has focused on point sources—primarily factories and sewage treatment plants.
Gains made in controlling such sources have often been offset by increasing levels of pollution from nonpoint sources such as:
city streets
lawns
farm fields

23. Controlling Nonpoint Pollution
In the United States, efforts to control nonpoint water pollution are still in their infancy.
They are gaining popularity because they are often economical solutions that offer other benefits as well.
The United States has focused more on groundwater pollution than nonpoint water pollution because groundwater is an important source of drinking water.

24. FIGURE 16: Schematic of sewage treatment
Stormwater drainage systems

25. FIGURE 18: Land disposal of sewage.

26. Sustainable Solutions for Water Pollution
Measures that will collectively serve to reduce our production of water pollutants include:
reducing consumption
recycling materials
reducing industrial waste and municipal sewage
using renewable resources
stabilizing population growth