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Chapter 21: Water Pollution PowerPoint PPT Presentation


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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

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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 2: Major sources of U.S. stream pollution


FIGURE 3: Sources of nonpoint water pollution affecting streams


FIGURE 5: The oxygen sag curve


FIGURE 6: Eutrophication and succession


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.


FIGURE 9: Thermal pollution


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.


FIGURE 16: Schematic of sewage treatment


FIGURE 18: Land disposal of sewage


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


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