Science behind Water Pollution

Water Pollution is defined as “the presence in water of harmful foreign substances. Both parts of this definition must be met. That is, the material must be harmful (must have the potential of damaging the health of humans or the environment or of interfering with some industrial process) and it must be foreign (pure sea water is not considered polluted, even though it is harmful to animals and plants that are adapted to freshwater). Water pollution is a severe problem; there are approximately 11,750 reported pollution incidents in the United States each year, involving an average of nearly 1,600 gallons each—a total pollutant load in the nation's waterways of some 18.6 million gallons annually. (This does not count permitted discharges of pollutants, which total several times this amount. Permitted industrial discharges of biochemical oxygen demand directly into the Great Lakes, for example—not counting discharges into tributaries or into municipal sewerage systems that then discharge into the Lakes—amount to approximately 100,000 tons per year.) The cost of U.S. water pollution abatement activities for all types of pollution, permitted and accidental, amounts to an average of about $10 billion annually.”[1] Although the world is covered 80% by water only 1% of this water is drinkable fresh water. “In the United States, more than 50 percent of our wetlands that recharge and purify ground water have been destroyed.”[2] The pH levels in lakes and rivers are affected by pollution. Usually the pH levels are right around 7; however this number can become more acidic with pollution. Acid rain is a negative effect of more acidic water.[3] Another side effect of water pollution is an excess amount of nutrients that lead to the creation of harmful algae. When there is too much algae covering the surface of the water and uses a lot of oxygen creating oxygen deprived zones, called “dead zones.”[4] Severe forms of pollution come from “polychlorinated biphenyls (PCBs)” which are highly toxic chemicals. One more kind of “toxic pollution comes from heavy metals, such as lead, cadmium, and mercury.”[5] Water pollution affects ecosystems starting at the vegetation level and working its way up to humans. If algae increases immensely and creates dead zones, while in other areas vegetation sores and fish are dying. People living in an area where this is happening would be devastated. Plants and animals that drink the water would not be able to survive in this environment. People would have no food source and no water source.

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[1] Ashworth, William, and Charles E. Little. "water pollution." Encyclopedia of Environmental Studies, New Edition. New York: Facts On File, Inc., 2001. Science Online. Facts On File, Inc. http://www.fofweb.com/activelink2.asp?ItemID=WE40&SID=5&iPin= envrnstud3423&SingleRecord=True (accessed May 13, 2010).

[2] http://www.epa.gov/gmpo/edresources/water_5.html

[3] http://pearl.maine.edu/windows/community/Water_Ed/pH/pH_whatisit.htm

[4] http://www.explainthatstuff.com/waterpollution.html

[5] http://www.explainthatstuff.com/waterpollution.html