Chapter 21: Water Pollution Sustainably Managing a Renewable Resource.

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

© A. B. Dowsett/Photo Researchers, Inc.

FIGURE 8:Fecal coliform bacteria

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 andtransported tothem 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 marinemammals, 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