Enzyme-Mediated Transformation of 17 Beta-Estradiol in Soil.

Widespread presence of reproductive hormones in soil and natural water bodies is drawing more and more attention because of its potential to influence public health and the environment. These hormones in the environment can interfere with normal biological behavior of human, aquatic, and wildlife animals. Among sexual steroidal hormones, 17beta-estradiol (E2) is the most potent, which is routinely released by human and animals and tend to be persistent in the environment. Land application of estrogen-containing solid wastes is considered as a major entry pathway of these hormones to natural water bodies via- surface runoff and/or leaching. Transformations of these hormones in soil impact the likelihood of their entry to water bodies. Previous studies have shown that certain extracellular enzymes that are involved in soil organic matter humification are capable of transforming such hormones into non-harmful products, but most of such studies were performed with aqueous experimental systems. Our study aims towards better understanding the behavior of hormone transformation in soils mediated by humification enzymes. Experiments were conducted using a sandy loam soil, preloaded with 17beta-estradiol, and with treatment of horseradish peroxidase or laccase at different levels. Significant removal of 17beta-estradiol was observed in samples with enzyme treatment in comparison to control samples to which enzymes were not applied. This study indicates that natural humification may play a major role in the environmental transformation and fate of hormones in soil and suggests that enzyme-enhanced humification process may serves as an efficient and, eco-friendly means to remediate hormones in soil, thus restricting their movement to water bodies.