Estrogen-related receptor disruption of source water and drinking watertreatment processes extracts

Environmental chemicals in drinking water can impact human health through nuclear receptors. Additionally, estrogen-relatedreceptors (ERRs) are vulnerable to endocrine-disrupting e ects. To date, however, ERR disruption of drinking water potency hasnot been reported. We used ERR two-hybrid yeast assay to screen ERR disrupting activities in a drinking water treatment plant(DWTP) located in north China and in source water from a reservoir, focusing on agonistic, antagonistic, and inverse agonistic activityto 4-hydroxytamoxifen (4-OHT). Water treatment processes in the DWTP consisted of pre-chlorination, coagulation, coal and sandfiltration, activated carbon filtration, and secondary chlorination processes. Samples were extracted by solid phase extraction. Resultsshowed that ERR antagonistic activities were found in all sample extracts, but agonistic and inverse agonistic activity to 4-OHTwas not found. When calibrated with the toxic equivalent of 4-OHT, antagonistic e uent e ects ranged from 3.4 to 33.1 g/L. In thetreatment processes, secondary chlorination was e ective in removing ERR antagonists, but the coagulation process led to significantlyincreased ERR antagonistic activity. The drinking water treatment processes removed 73.5% of ERR antagonists. To our knowledge,the occurrence of ERR disruption activities on source and drinking water in vitro had not been reported previously. It is vital, therefore,to increase our understanding of ERR disrupting activities in drinking water.