Identification and quantification of estrogen receptor agonists in wastewater effluents

Total concentrations of several known xenobiotic estrogen receptor (ER) ago nists and natural and synthetic estrogen were measured in water by use of a combination of instrumental and bioanalytical approaches. Samples from 3 m unicipal wastewater treatment plants (WWTPs) in south central Michigan (ups tream and effluent); 4 point source locations on the Trenton Channel of the Detroit River, MI; and 5 locations in Lake Mead, NV were analyzed. Organic compounds were extracted from 5 L water samples using solid-phase extracti on disks and separated into three fractions based on polarity. Whole extrac ts and fractions were tested for ER agonist potency using the MVLN in vitro bioassay. ER agonist potency was characterized by comparing the magnitude of induction elicited by the extractor fraction to the maximum induction ca used by 17 beta -estradiol (E2). The greatest concentrations of ER agonists were associated with the most polar fraction (F3). Instrumental analyses a nd further fractionation were used to identify specific ER agonists associa ted with bioassay responses. Bioassay data were compared to extract concent rations in order minimize variability associated with the extraction proced ure. Concentrations of endogenous estrogen, E2, and the synthetic estrogen ethynylestradiol (EE2) ranged from nondetectable to 14.6 ng/mL extract (non detectable to 3.66 ng/L water) and represented from 88 to 99.5% of the tota l estrogen equivalents in the water samples analyzed. Concentrations of alk ylphenols (APs) ranged from nondetectable to 148 mug/mL extract (nondetecta ble to 37 000 ng/L water). In general, alkylphenols contributed less than 0 .5% of the total estrogen equivalents in the water samples. Both bioassay-d irected fractionation results and comparison of ER agonist concentrations, adjusted for their known relative potencies, support the conclusion that E2 and EE2 were the dominant environmental estrogens in water samples from mi d-Michigan and Lake Mead, NV.