Reactions of Natural and Synthetic Hormones Mediated by Soil Enzymes

Natural estrogens, estrone (E1), 17-beta-estradiol (E2), and estriol (E3) and the synthetic estrogen, 17-alpha-ethinylestradiol (EE2) are among the most potent endocrine disruptors. Land application of animal wastes and biosolids is regarded as one of the major sources by which these hormones enter water through runoff or leaching. These chemicals elicit physiological response even at extremely low concentrations (~ ng/L), and thus constitute a major source of potential water contamination that challenges water treatment and environmental management practices. We have found that a number of extracellular soil enzymes are capable of mediating effective transformation of these estrogenic chemicals, and have systematically investigated the behaviors and mechanisms of such biochemical reactions as well as how such reactions may be influenced by soil components. The study indicates that enzyme-mediated biochemical transformation may play an important role in controlling the environmental transport and fate of hormonal contaminants in the soil/water environment, and suggests that such enzymatic reactions may be utilized in remediation or treatment practices to mitigate hormone release.