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Chapter 21: Water Pollution. Sustainably Managing a Renewable Resource. FIGURE CO: Water pollution in rich and poor countries of the world affects our health and economy. © Rubberball/Alamy Images. Point and Nonpoint Sources.
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Chapter 21: Water Pollution Sustainably Managing a Renewable Resource
FIGURE CO: Water pollution in rich and poor countries of the world affects our health and economy © Rubberball/Alamy Images
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
FIGURE 3: Sources of nonpoint water pollution affecting streams
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.
Toxic Organic Water Pollutants • Organics Sources: factories, homes, farms, lawns, and gardens. • Inorganic (acids and heavy metals, such as lead and mercury) Sources: Industry
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.
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.
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
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.
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
FIGURE 12: Oil spills from 1970 to 2006 Data courtesy of International Tanker Owners Pollution Federation Ltd., ITOPF
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
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
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
FIGURE S01_1: Algal blooms in the Great Lakes © John Sohlden/Visuals Unlimited
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
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
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.
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