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In vitro effects-based method and water quality screening model for use in pre- and post-distribution treated waters
Citation:
Medlock Kakaley, E., M. Cardon, N. Evans, L. Iwanowicz, J. Allen, E. Wagner, H. Hur, K. Bokenkamp, S. Richardson, M. Plewa, P. Bradley, K. Romanok, D. Kolpin, J. Conley, E. Gray, Philip Hartig, AND V. Wilson. In vitro effects-based method and water quality screening model for use in pre- and post-distribution treated waters. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 768:144750, (2021). https://doi.org/10.1016/j.scitotenv.2020.144750
Impact/Purpose:
The growing global human population has depleted many freshwater sources and increased reliance on effective drinking water treatment processes. Some isolated water contamination events have highlighted the importance of screening treated drinking water after treatment and distribution due to aging water distribution infrastructure. Bioassays, when run concurrently with analytical chemistry methods, have gained popularity over the last decade as effective tools to determine the efficacy of water treatment processes. Provided in the manuscript are methods to a highly sensitive method for detecting (anti)androgenic activity never before applied to water quality screening, as well as a tiered screening model for sample analysis applicable to routine water quality monitoring that expedites drinking water sample extract evaluation while maintaining statistical stringency. These methods could prove valuable to states and other localities beginning implement treated water quality testing with endocrine activity screening bioassays.
Description:
Recent urban public water supply contamination events emphasize the importance of screening treated drinking water quality after distribution. In vitro bioassays, when run concurrently with analytical chemistry methods, are effective tools to evaluating the efficacy of water treatment processes and water quality. We tested 49 water samples representing the Chicago Department of Water Management service areas for estrogen, (anti)androgen, glucocorticoid receptor-activating contaminants and cytotoxicity. We present a tiered screening approach suitable to samples with anticipated low-level activity and initially tested all extracts for statistically identifiable endocrine activity; performing a secondary dilution-response analysis to determine sample EC50 and biological equivalency values (BioEq). Estrogenic activity was detected in untreated Lake Michigan intake water samples using mammalian (5/49; median: 0.21 ng E2Eq/L) and yeast cell (5/49; 1.78 ng E2Eq/L) bioassays. A highly sensitive (anti)androgenic activity bioassay was applied for the first time to water quality screening and androgenic activity was detected in untreated intake and treated pre-distribution samples (4/49; 0.93 ng DHTEq/L). No activity was identified above method detection limits in the yeast androgenic, mammalian anti-androgenic, and both glucocorticoid bioassays. Known estrogen receptor agonists were detected using HPLC/MS-MS (estrone: 0.72–1.4 ng/L; 17α-estradiol: 1.3–1.5 ng/L; 17β-estradiol: 1.4 ng/L; equol: 8.8 ng/L), however occurrence did not correlate with estrogenic bioassay results. Many studies have applied bioassays to water quality monitoring using only relatively small samples sets often collected from surface and/or wastewater effluent. However, to realistically adapt these tools to treated water quality monitoring, water quality managers must have the capacity to screen potentially hundreds of samples in short timeframes. Therefore, we provided a tiered screening model that increased sample screening speed, without sacrificing statistical stringency, and detected estrogenic and androgenic activity only in pre-distribution Chicago area samples.
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DOI: In vitro effects-based method and water quality screening model for use in pre- and post-distribution treated waters