Degradation and transformation of 17α-estradiol in water–sediment systems under controlled aerobic and anaerobic conditions

Abstract

One of the principal metabolites in cattle excreta following the administration of Synovex® ONE, which contains estradiol benzoate and trenbolone acetate, is 17α-estradiol. As part of the environmental assessment of the use of Synovex ONE, data were generated to characterize the fate of 17α-estradiol in the environment. Studies were conducted to determine the degradation and transformation of 17α-[¹⁴ C]-estradiol in 2 representative water-sediment systems each under aerobic and anaerobic conditions. The same transformation products-estriol, 17β-estradiol, and estrone-were formed, principally in the sediment phase, under both conditions in both systems. From the production of these transformation products, the 50% disappearance time (DT50) values of estrone and 17β-estradiol were determined, along with the DT50 values of 17α-estradiol and the total drug (17α-estradiol + 17β-estradiol + estrone). The results indicate that 17 α-[¹⁴ C]-estradiol was more persistent under anaerobic conditions than under aerobic conditions and that 17 α-[¹⁴ C]-estradiol was less persistent than its transformation products. The DT50 values for the total system (aqueous and sediment phases) and for the total residues (17α-estradiol, 17β-estradiol, and estrone) were selected for use in modeling the environmental fate of estradiol benzoate. For aerobic degradation in the water-sediment system, the DT50 was 31.1 d, and it was 107.8 d for the anaerobic system. Environ Toxicol Chem 2017;36:621-629. © 2016 SETAC.