Waste and Pollution

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Pollution, contamination of Earth’s environment with materials that interfere with human health, the quality of life, or the natural functioning of ecosystems (living organisms and their physical surroundings). Although some environmental pollution is a result of natural causes such as volcanic eruptions, most is caused by human activities. Sidebars|

Climate Change 2001:The Scientific Basis|
The Intergovernmental Panel on Climate Change (IPCC) is an international group of scientists that evaluates scientific and technical information related to climate change and global warming (an increase in Earth’s surface temperature). The IPCC publishes an assessment of the latest scientific data related to climate change about every five years. In its Third Assessment Report, released in January 2001 and summarized here, the IPCC sharply increased its projections, predicting a global average surface temperature rise of 1.4 to 5.8°C (2.5 to 10.4°F) over the period 1990 to 2100 compared to a previous assessment of 1.0 to 3.5°C (1.8 to 6.3°F) for the same period. This IPCC report also for the first time identified human activity as the primary cause for global warming.| open sidebar|

There are two main categories of polluting materials, or pollutants. Biodegradable pollutants are materials, such as sewage, that rapidly decompose by natural processes. These pollutants become a problem when added to the environment faster than they can decompose (see Sewage Disposal). Nondegradable pollutants are materials that either do not decompose or decompose slowly in the natural environment. Once contamination occurs, it is difficult or impossible to remove these pollutants from the environment. Sidebars|

Health-Care Systems in Post-Colonial Africa|
Encarta Historical Essays reflect the knowledge and insight of leading historians. This collection of essays is assembled to support the National Standards for World History. In this essay, Oliver Osborne of the University of Washington argues that post-colonial rule and turmoil in Africa has not diminished the continent’s diverse health care systems but rather demanded collaboration among them.| open sidebar|

Nondegradable compounds such as dichlorodiphenyltrichloroethane (DDT), dioxins, polychlorinated biphenyls (PCBs), and radioactive materials can reach dangerous levels of accumulation as they are passed up the food chain into the bodies of progressively larger animals. For example, molecules of toxic compounds may collect on the surface of aquatic plants without doing much damage to the plants. A small fish that grazes on these plants accumulates a high concentration of the toxin. Larger fish or other carnivores that eat the small fish will accumulate even greater, and possibly life-threatening, concentrations of the compound. This process is known as bioaccumulation. | | II.| IMPACTS OF POLLUTION|

Minamata Disease Victims|
In the 1950s, residents of Minamata, Japan, began experiencing unusual symptoms, including numbness, vision problems, and convulsions. Several hundred people died. The cause was discovered to be mercury ingestion: A local industry had dumped the toxic chemical into Minamata Bay, poisoning fish and thousands of people. In 1997, after a massive cleanup, Japan announced that the bay had been cleared of the contaminant.| open sidebar|

Because humans are at the top of the food chain, they are particularly vulnerable to the effects of nondegradable pollutants. This was clearly illustrated in the 1950s and 1960s when residents living near Minamata Bay, Japan, developed nervous disorders, tremors, and paralysis in a mysterious epidemic. More than 400 people died before authorities discovered that a local industry had released mercury into Minamata Bay. This highly toxic element accumulated in the bodies of local fish and eventually in the bodies of people who consumed the fish....
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