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Water Pollution

• introduction of waste matter or chemicals that are harmful to organisms living in the water or to those that drink or are exposed to the water.

• the two underlying causes of water pollution are industrialization and rapid human population growth.

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Water Pollution

• Developed countries some water is still dangerously polluted.

• In developing parts of the world, water pollution is a big problem because polluted water may only be available

• Sources:

– point : actual pipe, source

– nonpoint : runoff from land

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Wastewater

• water that contains wastes from homes or industry.

– treatment plant make the water clean enough to return to a river or lake

– most waste biodegradable

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Sewage Sludge

• the solid material that remains after wastewater treatment

– dangerous concentrations of toxic chemicals makes it hazardous

• If the toxicity can be reduced to safe levels

– used as a fertilizer

– combined with clay to make bricks

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• Eutrophication is a natural process

• 1. Organic matter builds up in a body of water

• 2. Oxygen levels decrease,

• 3. Types of organisms change

• A body of water can become a swamp or marsh.

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Artificial Eutrophication

• process that increases the amount of nutrients in water through human activities

• major causes : fertilizer and phosphates in detergents.

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Thermal Pollution

• temperature increase in a body of water caused by human activity that has a harmful effect on water quality

– can cause large fish kills

– total disruption of an aquatic ecosystem

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Groundwater Pollution

• Usually from polluted surface water that percolates down

• Any pollution of the surface water in an area can affect the groundwater.

– Pesticides, herbicides, chemical fertilizer, and petroleum, industrial wastewater

– Leaking underground storage tanks are a major source of groundwater pollution

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Cleaning Up Groundwater Pollution

• Oof the most challenging environmental problems in the world.

• Groundwater recharges very slowly

– hundreds of years to recycle aquifer water and purge contaminants

– pollutants can cling to the materials that make up an aquifer, continue to cause problems

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Ocean Pollution

• Often dumped directly into the ocean

• At least 85 percent pollutants comes from activities on land

– oil, toxic wastes, and medical wastes

• Sensitive coastal ecosystems, such as coral reefs, most effected

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Oil Spills

• Each year, about 37 million gallons of oil from tanker accidents are spilled into the ocean.

– 5 percent of oil pollution in the oceans

• Most of the oil that pollutes the oceans comes from cities and towns..

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Water Pollution and Ecosystems

• Biomagnification : accumulation of pollutants at successive levels of the food chain.

– Alarming consequences for organisms at the top of the food chain

– One reason why U.S. states limit the amount of fish people can eat from certain bodies of water

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Cleaning Up Water Pollution

• The Clean Water Act of 1972 designed to “restore and maintain the chemical, physical, and biological integrity of the nation’s waters.”

– surface water clean enough for fishing and swimming by 1983 (not met)

– lakes fit for swimming increased by 30 percent,

– many states have passed stricter water-quality standards.

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• Marine, Protection, Research, and Sanctuaries Act of 1972: laws against ocean dumping.

• Oil Pollution Act of 1990 : requires all oil tankers traveling in U.S. waters to have double hulls by 2015 as an added protection against oil spills