Degradation of Steroid Hormones in Pig Manure

Steroid hormones are important potential contaminants found in natural systems, and can have endocrine disrupting effects. In recent years endocrine-disrupting chemicals (EDCs) have been considered to possibly affect the reproductive function of human beings and wildlife. Manure is one source of steroid hormones, is spread on agricultural soil regularly, and can potentially contaminate surface and groundwater resources. The objectives of this study were to examine the degradation pathways of 17β-estradiol, testosterone, and progesterone via microorganisms commonly found in manures. Also, the kinetics of the biodegradation of these compounds was examined. Degradation experiments were conducted under aerobic conditions in darkness at room temperature. Initial testosterone concentration was 3 μg L^-1. Samples were collected at regular intervals and analyzed by HPLC-DAD. Degradation products were detected, and their identification are currently being investigated by mass spectrometry. Preliminary data show that microorganisms in pig manure can degrade testosterone: 95% degradation of testosterone was observed after 17 hours in the non-sterile pig manure system. No significant loss of testosterone was observed for 29 hours in the no manure control system. There was a slight decrease (~4%) in testosterone concentration after one hour in the sterilized manure system, possibly due to sorption. These results suggest that manure-borne microorganisms might act to regulate testosterone concentrations in the environment.