You are here:
Cumulative assessment of steroid receptor mediated activity of contaminants in water samples using in vitro bioassays.
Citation:
Evans, N., J. Conley, M. Cardon, P. Hartig, AND V. Wilson. Cumulative assessment of steroid receptor mediated activity of contaminants in water samples using in vitro bioassays. SOT, San Antonio, Texas, March 11 - 15, 2018.
Impact/Purpose:
Assessment of various sources of water is important for human and ecological risk assessment. We studied the fate and transport of complex mixtures as they travel from a waste water treatment plant to a drinking water treatment plant. We found there to be hormonal activity in the effluent samples, but that activity disappears after the water goes through the drinking water treatment plant.
Description:
Cell-based assays could serve as a useful tool in the regulatory screening toolbox due to their high sensitivity and the ability to assess complex mixtures in which unknown compounds may be present. We have completed 3 major projects in collaboration with USGS: 1) Chemical Mixtures (surface water), 2) Source and Treated Drinking Water, and 3) Water Reuse. In each study, samples were extracted and assayed using T47D-KBluc and MDA-kb2 transactivation assays for estrogen receptor (ER) and androgen receptor (AR) activation, respectively. Glucocorticoid (GR) activation was detected using CV-1 cells transduced with hGR and a luciferase reporter construct. In the first two studies, ER mediated activity was the most frequently detected and was primarily explained by concentrations of estrone. There was limited detection of AR or GR mediated activity. For the Water Reuse project we examined the fate and transport of complex mixtures as they travel from a waste water treatment plant (WWTP) to a drinking water treatment plant (DWTP) across three seasonal sampling efforts (fall, spring, summer). Grab samples were collected upstream of WWTP, at WWTP effluent pipe, effluent mixing zone, downstream, DWTP intake, and treated drinking water. Polar Organic Chemical Integrative Samplers (POCIS) were deployed for 30 days each season at all locations except WWTP effluent and treated drinking water. ER activity was detected at low levels (<0.3ng E2Eq/L) in most grab samples, but was highest (1.4-28.6ng E2Eq/L) at the effluent pipe in all seasons. AR and GR activity was only detected in the effluent grab samples (2ng DHTEq/L; 20ng DexEq/L, respectively) and was significantly lower in summer than fall and spring. ER activity in the POCIS samples was highest in the spring at the upstream and mixing zone sites. Importantly, ER activity was below quantifiable limits in the treated drinking water in grab and POCIS samples. No GR activity was detected in the POCIS samples. Overall, cell-based assays and analytical chemistry are complements that allow us to gather more robust data on the possible effects of contaminants in various water sources. This abstract does not reflect USEPA policy.