Chapter 21

Water Pollution


1.      List seven types of water pollutants and give an example of each. List three strategies to determine the presence of infectious agents in water.


2.      Distinguish between point and nonpoint sources of pollution. Summarize the three major sources of water pollution.


3.      Draw an oxygen sag curve to illustrate what happens to dissolved oxygen levels in streams below points where degradable oxygen-demanding wastes are added. Compare problems of lake water pollution to those of stream pollution.


4.      Describe the difference between eutrophication and cultural eutrophication. How can cultural eutrophication be prevented or cleaned up? State three lessons learned by the Great Lakes case study.


5.      Describe what is happening to the quality of coastal waters and how coastal waters can be protected. State one ecological principle illustrated by the Chesapeake Bay case study. Describe the status of ocean dumping and oil spills in the ocean. List eight ways to prevent and four ways to cleanup coastal water pollution.


6.      List the major pollutants of groundwater. Explain why cleanup of groundwater is so difficult.  List six ways to prevent and three ways to cleanup groundwater pollution.


7.      Briefly describe two major laws that protect water quality in the United States. State three strategies to reduce nonpoint pollution. Briefly describe and distinguish among primary, secondary, and tertiary sewage treatment.


8.      Discuss how public drinking water is purified and how the U.S. Safe Drinking Water Act helps to ensure that drinking water is clean.


9.      List three strategies to shift emphasis from pollution cleanup to pollution prevention strategies and several ways that individuals can contribute to a reduction in water pollution.


Key Terms  (Terms are listed in the same font style as they appear in the text.)

advanced (tertiary) sewage treatment (p. 511)

biological oxygen demand (BOD)

cultural eutrophication (p. 499)

dissolved oxygen (DO) (p. 496)

eutrophication (p. 499)

nonpoint sources (p. 494)

oxygen-demanding wastes  (p. 504)

point sources (p. 494)

primary sewage treatment (p. 510)

secondary sewage treatment (p. 510)

septic tank (p. 510)

water pollution (p. 494)