Citation:

Wilson, V., J. Conley, N. Evans, M. Cardon, L. Rosenblum, L. Iwanowicz, P. Hartig, K. Schenck, AND P. Bradley. In vitro assessment of estrogen, androgen, and glucocorticoid bioactivity in a nationwide screen of United States stream waters. Society of Toxicology, Baltimore, MD, March 12 - 16, 2017.

Impact/Purpose:

This study measured in vitro ER, AR and GR mediated activity in surface waters in a collaborative study with the USGS who conducted an extensive suite of chemical analyses of the same samples. The utility of in vitro assays in water quality monitoring was evident from both the agreement between ER/AR activity and estrogen/androgen concentrations, as well as the detection of GR activity for which there were no chemical detections of GR active compounds, which signals that additional chemical analyses are needed to identify the causative compounds for GR activity.

Description:

In vitro bioassays can identify environmental samples contaminated with bioactive chemicals that interact with steroid receptors and provide a cumulative, effect-based measurement of contamination. We measured in vitro estrogen (ER), androgen (AR), and glucocorticoid receptor (GR) activity, along with a suite of chemical analytes, in stream water across the US. Samples were analyzed from 35 sites, including 3 reference watersheds and 32 watersheds impacted by multiple, well-characterized contaminant sources. ER activity was the most frequently detected with 34/35 samples displaying activity (range, 0.054–115.8 ng E2Eq L-1) above the assay reporting limit. Seven of 35 sites were at or above levels estimated to result in adverse effects in aquatic organisms (~1 ng E2Eq L-1). There was strong agreement (r2=0.918) between in vitro ER activity and concentrations of estrogens after correcting for the in vitro potency of each compound. AR activity was only detected in 5/35 samples (range, 1.60–4.76 ng DHTEq L-1). GR activity was detected in 9/35 samples (range, 6.0–43.4 ng DexEq L-1), however, there were no detections of known GR active compounds among those on the instrumental chemical analyte list. The utility of in vitro assays in water quality monitoring was evident from both the agreement between ER/AR activity and estrogen/androgen concentrations, as well as the detection of GR activity for which there were no chemical detections of GR active compounds, which signals that additional chemical analyses are needed to identify the causative compounds for GR activity. More work, however, is needed to fully implement these technologies into the current water quality monitoring regulatory framework. This abstract does not necessarily reflect US EPA policy.

Record Details: