Degradation of Five Selected Endocrine-Disrupting Chemicals in Seawater and Marine Sediment

Abstract

We studied degradation of five endocrine-disrupting chemicals (EDCs), namely bisphenol A (BPA), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), 4 -tert- octyl phenol (4- t -OP), and 4- n -nonyl phenol (4- n -NP), in the marine environment using a marine sediment and seawater collected from the coastal area near Adelaide, South Australia. This laboratory study showed that all five EDCs were degraded in seawater within 56 days. However, a lag phase preceding their rapid degradation in seawater was observed for BPA, E2, and EE2. On the other hand, 4- t -OP and 4- n -NP dissipated rapidly due to abiotic as well as biotic factors without any lag phase. Under the aerobic conditions, the five EDCs were found to degrade in the sediment, with E2 and 4- n -NP showing fastest degradation, with estimated half-lives of 4.4 and 5.8 d, respectively, followed by BPA ( t 1/ 2 14.5 d), EE2 ( t 1/2 >20 d), and 4- t -OP ( t 1/2 >20 d). Under anaerobic conditions in the marine sediment, little or no degradation of the five EDCs was noted, except E2 which showed a slow continuous degradation rate during the 70-day study. Approximately 50% of E2 was degraded after 70 d anaerobic incubation. The study showed that the five EDCs studied here will degrade relatively rapidly under aerobic conditions in marine sediment and seawater but are likely to show much longer persistence under anoxic conditions.