Assessment of Estrogenicity and Estrogenicity Drivers in a WWTP Mixing Zone

The persistence and toxicity effects of endocrine-disrupting chemicals, including environmental estrogens, have not been well-characterized in wastewater treatment plant mixing zones. This study examines the levels of environmental estrogens present in the mixing zone of a shallow effluent-receiving stream in Charlottesville, VA and determines the key compounds that drive the estrogenicity in this portion of the stream. The endogenous estrogen, 17β-estradiol, and the plasticizer bisphenol-A were measured at concentration ranges of 10–176 ng/L, and 0–12 ng/L, respectively. The WWTP was found to be the main source of these compounds. Other known environmental estrogens were not detected at significant levels; hence 17β-estradiol is believed to be the driver of estrogenicity. Analysis of the bed sediments did not yet detectable levels of the target compounds likely due to the very low organic fraction of the sediments.