ABSTRACT
This chapter reviews the literature pertaining to the role of biodegradation in determining the concentration of organic chemicals in aquatic and terrestrial environments. Biodegradation, or the transformation of chemical compounds by the action of living organisms, is one of the major processes that determine the fate of organic chemicals in aquatic and terrestrial environments. Microorganisms play a major role in biodegradation because of their abundance, species diversity, catabolic versatility, high metabolic activity, and their ability to adapt to a wide variety of environmental conditions. Aquatic environments, both freshwater and marine, represent the major ecosystem on earth. One of the most important aspects of terrestrial microbial ecology concerns the existence of discrete microbial habitats. This concept is derived from the fact that soils are heterogeneous, discontinuous, structured environments which are dominated by a solid phase. The increased stability of free enzymes in soils appears to be due to the association of the protein molecules with clay particles.
