Potential estrogenic effects of wastewaters on gene expression in Pimephales promelas and fish assemblages in streams of southeastern New York

Barry P Baldigo, Scott D George, Patrick J Phillips, Jocelyn D C Hemming, Nancy D Denslow, Kevin J Kroll

Direct linkages between endocrine-disrupting compounds (EDCs) from municipal and industrial wastewaters and impacts on wild fish assemblages are rare. The levels of plasma vitellogenin (Vtg) and Vtg mRNA in male fathead minnows Pimephales promelas (FHMs) exposed to wastewater effluents and dilutions of 17α-ethinylestradiol (EE2), estrogen activity, and fish assemblages in 10 receiving streams were assessed to improve our understanding of important interrelations. Results from 4-d laboratory assays indicate that EE2, plasma Vtg concentration and Vtg-gene expression in FHMs, and 17β-estradiol equivalents (E2Eq) were highly related to each other (R(2 ) = 0.98 to 1.00). Concentrations of E2Eq in most effluents did not exceed 2.0 ng/L, which was possibly a short-term exposure threshold for Vtg-gene expression in male FHMs. Plasma Vtg in FHMs only increased significantly (up to 1136 µg/mL) in two wastewater effluents. Fish assemblages were generally unaffected at 8 of 10 study sites, yet the density and biomass of 79% to 89% of species populations were reduced (63 to 68% were reduced significantly) in the downstream reach of one receiving stream. These results, and moderate to high E2Eq concentrations (up to 16.1 ng/L) observed in effluents during a companion study, suggest that estrogenic wastewaters can potentially affect individual fish, their populations, and entire fish communities in comparable systems across New York. This article is protected by copyright. All rights reserved.