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Occurrence and in vitro bioactivity of estrogen, androgen, and glucocorticoid compounds in a nationwide screen of United States stream waters
Citation:
Conley, J., N. Evans, M. Cardon, L. Rosenblum, L. Iwanowicz, P. Hartig, K. Schenck, P. Bradley, AND V. Wilson. Occurrence and in vitro bioactivity of estrogen, androgen, and glucocorticoid compounds in a nationwide screen of United States stream waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 51(9):4781-4791, (2017).
Impact/Purpose:
The Chemical Mixtures and Environmental Effects study is a nation-wide interagency, collaborative investigation between the US Geological Survey (USGS) and the US Environmental Protection Agency (USEPA). The goals of the study are to better define what chemicals occur in streams of the U.S. and their concentrations, what land-use practices influence the composition of chemical mixtures, and whether exposure of fish and other aquatic organisms to these mixtures may result in adverse health effects. Here, we describe the results of in vitro estrogen receptor (ER), androgen receptor (AR), and glucocorticoid receptor (GR) transcriptional activation assays and compare the results with reported concentrations of known estrogens, androgens, and glucocorticoids in samples from this nationwide survey. Results presented in this manuscript may be used by scientists and risk assessors for estimating the potential for adverse effects on aquatic organisms from exposure to site waters with elevated, receptor-based biological activity, as well as regulatory entities who are pursuing the use of in vitro bioassays in water quality monitoring frameworks as a complement to analytical chemical evaluations. This manuscript represents the largest scale survey of surface waters across the United States conducted to date integrating both chemical and in vitro biological results as a proof-of-concept for an integrated, tiered screening strategy for more thorough evaluation of water quality.
Description:
In vitro bioassays are sensitive, effect-based tools used to quantitatively screen for chemicals with nuclear receptor activity in environmental samples. We measured in vitro estrogen (ER), androgen (AR), and glucocorticoid receptor (GR) activity, along with a suite of chemical analytes, in stream water from 35 well-characterized sites (3 reference and 32 impacted) across 24 states and Puerto Rico. ER agonism was the most frequently detected with nearly all sites (34/35) displaying activity (range, 0.054–115.8 ng E2Eq L-1). There was a strong linear relationship (r2=0.918) between in vitro ER activity and concentrations of estrogenic compounds after correcting for the in vitro potency of each compound. AR agonism was detected in 5/35 samples (range, 1.60–4.76 ng DHTEq L-1) and corresponded well with detections of androgenic chemicals. GR agonism was detected in 9/35 samples (range, 6.0–43.4 ng DexEq L-1), however, none of the recognized GR-active compounds on the target-chemical analyte list were detected. The utility of in vitro assays in water quality monitoring was evident from both the quantitative agreement between ER activity and estrogen concentrations, as well as the detection of GR activity for which there was no corresponding GR-active chemical-target detections. Incorporation of in vitro bioassays as complements to chemical analyses in standard water quality monitoring efforts would allow for more complete assessment of the chemical mixtures present in many surface waters.
