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Removal and Transformation of Estrogens During the Coagulation Process
Citation:
SCHENCK, K. M., N. DUGAN, L. J. WYMER, D. WILLIAMS, H. MASH, T. F. SPETH, L. Rosenblum, T. E. Wiese, AND B. Merriman. Removal and Transformation of Estrogens During the Coagulation Process. Presented at US EPA, ORD and Association of State and Interstate Water Pollution Control Administration Webinar, Cincinnati, OH, August 20, 2009.
Impact/Purpose:
To inform the public.
Description:
Estrogenic compounds have been shown to be present in surface waters, leading to concerns over the possible presence of endocrine disrupting compounds in finished drinking waters. Bench-scale studies (jar tests) simulating coagulation were conducted to evaluate the ability of two coagulants, alone and in combination with powdered activated carbon (PAC) or chlorine, to remove three estrogens, 17β-estradiol, 17α-ethynylestradiol, and estriol from Ohio River water. Coagulation alone, with either alum or ferric chloride, did not result in significant removals of the estrogens. The addition of PAC resulted in removals ranging from approximately 20 to 80 percent. Treatment of the estrogens with chlorine, either alone or with coagulant, resulted in approximately 98 percent reductions in the concentrations of the parent estrogens, accompanied by the formation of by-products. Two in vitro bioassays, the MVLN reporter gene assay and the MCF-7 cell proliferation assay, were used to characterize the estrogenic activity of the chlorinated water samples containing residual parent estrogen and by-products. The observed estrogenic activities of the chlorinated samples were not significantly different from those predicted based on the concentrations of the residual parent estrogen, indicating that the chlorination by-products did not contribute appreciably to the estrogenic activity.