Persistence and fate of 17β-estradiol and testosterone in agricultural soils Original Research Article

Steroidal hormones are constantly released into the environment by man-made and natural sources. The goal of this study was to examine the persistence and fate of 17β-estradiol and testosterone, the two primary natural sex hormones. Incubation experiments were conducted under aerobic and anaerobic conditions using [4-14C]-radiolabeled 17β-estradiol and testosterone. The results indicated that 6% of 17β-estradiol and 63% of testosterone could be mineralized to 14CO2 in native soils under aerobic conditions. In native soils under anaerobic conditions, 2% of testosterone and no 17β-estradiol was methanogenized to 14CH4. Essentially, no mineralization of either testosterone or 17β-estradiol to 14CO2 occurred in autoclaved soils under aerobic or anaerobic condition. Results also indicated that 17β-estradiol could be transformed to an unidentified polar compound through abiotic chemical processes; however, 17β-estradiol was only oxidized to estrone via biological processes. The TLC results also indicated that testosterone was degraded, not by physical–chemical processes but by biological processes. Results also indicated that the assumed risks of estrogenic hormones in the environment might be over-estimated due to the soil’s humic substances, which can immobilize majority of estrogenic hormones, and thereby reduce their bioavailability and toxicity.