Page 436 - Environment: The Science Behind the Stories

Assess problems of water supply and propose • Water pollutants include toxic chemicals, microbial patho-
solutions to address depletion of fresh water gens, excessive nutrients, biodegradable wastes, sediment,
and thermal pollution. (pp. 426–427, 430)
• Desalination increases water supply, but it is expensive and
energy-intensive. (p. 423) • Groundwater pollution is more persistent and difficult to
address than surface water pollution. (pp. 430–431)
• Solutions to reduce demand include technology, market-
based approaches, and consumer products that increase • Legislation and regulation have improved water quality in
efficiency in agriculture, industry, and the home. (pp. developed nations in recent decades. (p. 431–432)
423–425)
Explain how we treat drinking water and wastewater
• Privatization of water supplies is a much-debated issue.
(p. 425) • Municipalities treat drinking water by filtering and disin-
fection in a multistep process. (p. 432)
• Political tensions over water may heighten in the near
future. (pp. 425–426) • Septic systems help treat wastewater in rural areas. (p. 432)
• Wastewater is treated physically, biologically, and chemi-
Describe the major classes of water pollution cally in a series of steps at municipal wastewater treatment
and propose solutions to address water pollution facilities. (pp. 432–433)
• Water pollution stems from point sources and non-point • Artificial wetlands enhance wastewater treatment while
sources. (p. 426) restoring habitat for wildlife. (pp. 432, 434)

testing your Comprehension

1. Compare and contrast the main types of freshwater eco- 6. Name some point and non-point sources of water pollu-
systems. Name and describe the major zones of a typical tion. Which of the two (point source or non-point source)
pond or lake. is more difficult to identify?
2. Is bottled water always healthier than tap water? 7. Define groundwater. Why do many scientists consider
3. Describe three benefits and three costs of damming riv- groundwater pollution a greater problem than surface
ers. What particular environmental, health, and social water pollution?
concerns has China’s Three Gorges Dam and its reservoir 8. What are some anthropogenic (human) sources of
raised? groundwater pollution?
4. With reference to the diversion of water from the 9. Describe how drinking water is treated. How does a sep-
Colorado River, what is meant by the statement, “We are tic system work?
truly ‘replumbing the planet’ ”? 10. Describe and explain the major steps in the process of
5. Why are water tables dropping around the world? What wastewater treatment. How can artificial wetlands aid
are some negative impacts of falling water tables? such treatment?

Seeking Solutions CHAPTER 15 • Fr E shwat E r s yst E m s and rE sour CE s

1. How can we lessen agricultural demand for water? 4. Have the provisions of the Clean Water Act been effective?
Describe some ways we can reduce household water use. Discuss some of the methods we can adopt, in addition to
How can industrial uses of water be reduced? “end-of-pipe” solutions, to prevent water pollution.
2. How might desalination technology help “make” more 5. tHINk It tHRoUgH Your state’s governor has put you in
water? Describe two methods of desalination. Why is this charge of water policy for the state. The aquifer beneath
technology mostly being used in places like Saudi Arabia? your state has been overpumped, and many wells have
3. Describe three ways in which your own actions contrib- run dry. Agricultural production last year decreased for
ute to water pollution. Now describe three ways in which the first time in a generation, and farmers are clamoring
you could diminish these impacts. for you to do something. Meanwhile, the state’s largest 435

M15_WITH7428_05_SE_C15.indd 435 12/12/14 2:20 PM