AWWA WQTC58975

A recent U.S. Geological Survey study has demonstrated that surface waters in the state of Arizona have widespread contamination of endocrine disrupting compounds (EDCs) and including various estrogenous compounds. Little is known about the fate of EDCs in drinking water treatment processes. Most of the water treatment plants around the nation use chlorine as a disinfectant. The ability of HOCl to oxidize organic compounds with amine functional groups and/or cyclic nitrogen is well established. Many of the EDC/PPCP compounds contain benzene rings, which impact their reactivity with chlorine and the transformed product can also show varying degree of estrogenicity. The issue becomes especially important in light of the fact that these chemicals occur at trace concentration levels. The objective of this study was to characterize the type of estrogenicity found in source water and its response to advanced water treatment processes, which can help in understanding the removal and transformation of EDCs from drinking water. The water samples from the Verde River, the Salt River, the Central Arizona Project (CAP) canal, and two local water treatment plants were collected in amber glass bottles on a monthly basis. The water samples were split into two sets before concentration. One set of samples was chlorinated and the other set was kept untreated. Both the sets were concentrated by liquid-liquid extraction using Dichloromethane. The concentrated samples were assayed for the presence of Endocrine Disrupting Chemicals (estrogenic) by using MCF cell line grown in 12 well plates. The 17b-estradiol was used as standard in all cell proliferation assays. The Relative Proliferation Effect (RPE) for source and finished waters were calculated. The estrogenicity in water from the Salt River, the Verde River, CAP canal, raw water from water treatment plant 1 (WTP1) and water treatment plant 2 (WTP2) averaged at 62.46%, 66.69%, 63.06%, 35.87%, and 29.87%. These levels suggest the presence of partial to fully agonistic chemicals in these source waters. The relative proliferation effect for finished water from WTP2 and WTP1 averaged at 24.31% and 23.58%, suggesting that treatment processes were able to reduce the levels of estrogenic chemicals during water treatment processes. The relative proliferation effect for chlorinated raw waters from all sources were found to be always less than respective unchlorinated raw waters but greater than finished drinking water. This approach shows a promise to comprehensively evaluate the effectiveness of advanced treatment processes to mitigate cumulative estrogenicity in drinking water. Includes figures.