الفهرس | Only 14 pages are availabe for public view |
Abstract ” Pollution is the price of maintaining and improving our standard of living. Many noxious and toxic chemical substances, natural and synthetic, are involved in processing raw materials, in manufacturing fmished goods, and in providing essential services. Pollutants are thus direct products or indirect by-products of our technologic processes. Pollution is the most serious of all environmental problems and poses a major threat to the health and well-being of millions of people and global ecosystems. Other major environmental problems are either wholly or partly caused by pollution; these include global warming, climatic change and the loss ofbiodiversity through the extinction of many species. In the future, environmental pressures can only increase as a result of population growth and the expectation of higher living standards (AlIoway and Ayres, 1993). Pollutants from different sources are introduced to the environment so that it is seldom are we exposed to a single pollutant. Significantly exposure to combinations of pollutants may produce different effects from those that would result from exposure to each pollutant separately. The combined effect may be purely additive, synergistic, antagonistic or potentiative-interactions that determine the consequences of simultaneous exposure and thus the maximum permissible concentration of pollutants coexisting in a particular environment (Slonim, 1974). |