Environmentalists often voice concern about threats like acid rain, carbon dioxide buildup in the atmosphere, water contamination, and declining biodiversity. Recently, many have come to recognize another equally serious threat called biological pollution.
Biological pollution is the movement of living organisms, either accidentally or intentionally, from the places where they evolved to new environments where a lack of natural enemies permits their population to explode. These organisms, sometimes called invasive exotic pests, threaten our crops, our forests, and perhaps even our very existence. Biological pollutants, like chemical pollutants, are here because of human activities. But unlike chemical pollutants, biological pollutants cannot be reduced or prevented by legislation. Once biological pollutants are imported, they grow, adapt, multiply and spread on their own unless direct, vigorous, and often costly actions are taken to stop them.
