| Natural and synthetic estrogens have been found in bays associated with nearby municipal facilities at levels known to disrupt the endocrine systems of aquatic species. Santa Monica Bay (SMB) receives inputs of treated wastewater from 2 of the larger wastewater treatment plants (WWTP) in the world, highlighting this bay as a potential at-risk area for endocrine disruption. We investigated possible exposure effects of released effluent on endogenous steroid levels of 3 resident flatfishes, Pacific sanddab (Citharichthys sordidus ), English sole (Parophrys vetulus) and hornyhead turbot (Pleuronichthys verticalis), specifically, E2, T, 11-KT, and pharmaceutical EE2. Overall, seasonal fluctuations in steroid levels were observed corresponding to expected reproductive activity. Hornyhead turbot exhibited dramatically high E2 levels, with significantly higher levels in males at outfall locations; outfall-associated trends in E2 and T were observed in Pacific sanddab and English sole. EE2 was reported across all species at minimum levels, with significant levels seen in active females at outfall locations. The findings herein imply that exogenous contaminants, potentially including human-derived sex steroids, are being released into SMB and may impact endogenous levels of endocrine hormones in aquatic residents. Additional research is warranted to better understand the fate of effluent-released steroids and other contaminants. |
