Citation:

Medlock Kakaley, E., B. Blackwell, M. Cardon, J. Conley, N. Evans, D. Feifarek, E. Furlong, S. Glassmeyer, L. Gray, P. Hartig, D. Kolpin, M. Mills, L. Rosenblum, D. Villeneuve, AND V. Wilson. De Facto Water Reuse: Bioassay suite approach delivers depth and breadth in endocrine active compound detection. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 699(134297):1, (2020). https://doi.org/10.1016/j.scitotenv.2019.134297

Impact/Purpose:

The existence of complex mixtures of anthropogenically-derived chemicals in freshwater environments has long been established yet not all waste and drinking water treatment processes eliminate contaminants equally. In this study we assessed the presence of emerging contaminants of concern (focusing in general on endocrine disrupting compounds) in waste water effluent and the contributions on compound degradation from both the natural processes in the river and a downstream drinking water treatment plant. We used several non-targeted effects-based methods, whose activated endpoints correspond with physiological adverse outcomes, as well as complimentary targeted analytical chemistry methods. We found that the effluent produced the greatest relative biological activity and contained the highest concentration of steroidal estrogens. While the reported biological activity and estrogen concentrations significantly decreased downstream, with almost all activity reported below method limits of detection in the unfinished treated drinking water. This multi-faceted approach for screening water quality not only increased our confidence in reporting the presence of potential compounds that activate specific adverse outcomes, but is quickly gaining recognition in the field.

Description:

Although endocrine disrupting compounds have been detected in wastewater and surface waters worldwide using a variety of in vitro effects-based screening tools, e.g. bioassays, few have examined potential attenuation of environmental contaminants by both natural (sorption, degradation, etc.) and anthropogenic (water treatment practices) processes. This study used several bioassays and quantitative chemical analyses to assess residence-time weighted samples at six sites along a river in the northeastern United States beginning upstream from a wastewater treatment plant outfall and proceeding downstream along the stream reach to a drinking water treatment plant. Known steroidal estrogens were quantified and changes in signaling pathway molecular initiating events (activation of estrogen, androgen, glucocorticoid, peroxisome proliferator-activated, pregnane X receptor, and aryl hydrocarbon receptor signaling networks) were identified in water extracts. In initial multi-endpoint assays geographic and receptor-specific endocrine activity patterns in transcription factor signatures and nuclear receptor activation were discovered. In subsequent single endpoint receptor-specific bioassays, estrogen (16 of 18 samples; 0.01 to 28 ng estradiol equivalents [E2Eqs]/L) glucocorticoid (3 of 18 samples; 1.8 to 21 ng dexamethasone equivalents [DexEqs]/L), and androgen (2 of 18 samples; 0.95 to 2.1 ng dihydrotestosterone equivalents [DHTEqs]/L) receptor transcriptional activation occurred above respective assay method detection limits (0.04 ng E2Eqs/L, 1.2 ng DexEqs/L, and 0.77 ng DHTEqs/L) in multiple sampling events. Estrogen activity, the most often detected, correlated well with measured concentrations of known steroidal estrogens (r2 = 0.890). Overall, activity indicative of multiple types of endocrine active compounds was highest in wastewater effluent samples, while activity downstream was progressively lower, and negligible in unfinished treated drinking water. Not only was estrogenic and glucocorticoid activity confirmed in the effluent by utilizing multiple methods concurrently, but other activated signaling networks that historically received less attention (i.e. peroxisome proliferator-activated receptor) were also detected.

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