University of California Water Resources Center

Endocrine disrupting agents encompass a vast array of compounds that have multiple biological targets and degrade water quality, especially if this water is to be re-used for groundwater recharge or agricultural practices. Antiestrogenic and estrogenic activities and chemicals have been observed in effluents from full secondary treatment. Assuming that estrogens and antiestrogens are present in wastewater effluent, the overall aim of this study is to assess the efficiency of treatment processes for the removal of these compounds in one of the major water reclamation producers in the western United States: the Orange County Water District. Utilizing an in vivo bioassay developed in the PI’s laboratory effluents were evaluated after various water treatment processes for the occurrence of estrogenic and antiestrogenic compounds. Treatment processes included reverse osmosis, filtration/chlorination of secondary effluent, ground water filtration, and wetland treatment. In vivo estrogenic activity was observed in fish exposed to effluent treated with filtration/chlorination (which is subsequently used for non-potable purposes), ground water and constructed wetlands. No activity was observed in reconstituted water that had been treated with reverse osmosis. Our results also suggest that in vitro assays based solely on estrogen receptor ligand activity (YES) may underestimate estrogenic activity of sampled water. Although not as robust a measurement as estrogenic activity, in vivo antiestrogenic activity was observed in fish exposed to wastewater samples treated with filtration/chlorination and the wetland. Moreover, wastewater after the wetland treatment seemed to have more antiestrogenic activity than before the treatment. These data indicated the occurrence of antiestrogenic and estrogenic compounds in water following various treatment processes. It is recommended that source identification be considered in future studies utilizing chromatographic fractionation methods to better understand the potential risk associated with these compounds in reclaimed water.