Characterization of Endocrine Disrupting Chemicals in SourceWaters in Central Arizona

摘要

Occurrence of endocrine disrupting compounds (EDCs), and pharmaceutically active chemicals personal care products (PPCP)s in the source water has been reported extensively. Removal of such chemicals during water treatment processes is a particularly difficult task for drinking water utilities. Compounds with estrogenic properties have become focal point because ofrntheir ability to interfere with the mammalian reproductive system. Compounds suspected of having such capability include a wide variety of natural and synthetic chemical and their degradation products. Many of these chemicals are present in water supplies because of their polarity and recalcitrant nature.rnA recent U.S.G.S study has demonstrated that surface waters in the state of Arizona have widespread contamination of endocrine disrupting compounds 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 the face of the fact that these chemicals occur at tracernconcentration levels. Therefore it is essential to characterize the type of estrogenicity found inrnsource water and its response to advanced water treatment processes, which can help inrnunderstanding the removal and transformation of EDCs from drinking water.rnThe water samples from the Verde River, the Salt River, the Central Arizona Projectrn(CAP) canal, and two local water treatment plants were collected in amber glass bottles onrnmonthly basis. The water samples were split into two sets before concentration. One set of samplernwas chlorinated and other set was kept untreated. Both the sets were concentrated by liquid-liquidrnextraction using Dichloromethane. The concentrated samples were assayed for the presence ofrnEndocrine Disrupting Chemicals (estrogenic) by using MCF cell line grown in 12 well plates. Thern17b-estradiol was used as standard in all cell proliferation assays.rnThe Relative Proliferation Effect (RPE) for source and finished waters were calculated. Thernestrogenicity in water from Salt river, Verde river, CAP canal, raw water from water treatmentrnplant 1(WTP1) and water treatment plant 2 (WTP2) averaged at 62.46%, 66.69%, 63.06%,rn35.87%, and 29.87%. These levels suggest presence of partial to fully agonistic chemicals in thesernsource 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.