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EVALUATION OF THE REMOVAL OF ESTROGENS FOLLOWING CHLORINATION
Citation:
SCHENCK, K. M., D. WILLIAMS, N. DUGAN, H. MASH, T. F. SPETH, L. J. WYMER, B. MERRIMAN, L. Rosenblum, AND T. Wiese. EVALUATION OF THE REMOVAL OF ESTROGENS FOLLOWING CHLORINATION. Presented at Society of Environmental Toxicology and Chemistry- Tampa Convention Center, Tampa, FL, November 16 - 20, 2008.
Impact/Purpose:
Poster Presentation
Description:
A number of estrogenic compounds have been shown to be present in surface waters in the U.S. These compounds have the potential to act as potent endocrine disrupting chemicals (EDCs). Although there has not yet been a determination of risks posed by EDCs in finished drinking waters, it is prudent to explore if strategies already employed to manage other drinking water risks can also manage potential risks associated with EDCs. Chlorine, commonly used as a disinfectant in water treatment, can also be added during the coagulation process to enhance the removal of organic contaminants. Bench-scale studies (jar tests), which simulate the coagulation process, were conducted to evaluate the ability of chlorine to remove three estrogens (estradiol, ethynylestradiol, and estriol) from Ohio River water. The estrogen to be evaluated was added to the river water prior to treatment. Coagulant doses were selected based on turbidity removal. Chlorine doses were selected based on the chlorine demand of the raw water and the production of a post-treatment chlorine residual of approximately 1 mg/L, within the range typical of drinking waters in the U.S. A quenching agent (sodium ascorbate) was added to each sample containing residual chlorine. Treatment efficacy was evaluated analytically by comparing the estrogen concentrations in the control and treatment jars using solid phase extraction followed by liquid chromatography/mass spectroscopy. Two in vitro bioassays, the MVLN reporter gene assay and the MCF-7 cell proliferation assay, were used to determine the levels of estrogenic activity present in the water samples before and after treatment. Previous jar test studies have shown that coagulation (using alum or ferric chloride) alone did not result in estrogen removal and that the effect of chlorine was independent of the presence of coagulant. Present study results showed treatment of the estrogens with chlorine resulted in approximately 98 percent reductions in the concentrations of the parent estrogens. This reduction is due to chemical transformation of the estrogens. Analysis of the in vitro bioassay data suggests that the chlorination by-products do not contribute to the level of estrogenic activity present in the treated water samples.