Biological Cycles for Toxic Elements in the Environment

Abstract

Some of the chemical and biochemical transformations of toxic elements in the environment are discussed with special emphasis on the role played by microorganisms. When confronted with a toxic substance, microorganisms frequently adapt to detoxify it. However, the detoxification of a substance by microorganisms can yield a product that is either more or less toxic to higher organisms. The detoxification mechanisms of mercury are used as examples to demonstrate that there are biological cycles for the synthesis and degradation of toxic compounds. It is also shown that our present knowledge of the biologial cycles of toxic elements enables us to predict the behavior of other toxic elements in the environment.