Evidence that watershed nutrient management practices effectively reduce estrogens in environmental waters

We evaluate the impacts of different nutrient management strategies on the potential for co-managing estrogens and nutrients in environmental waters of the Potomac watershed of the Chesapeake Bay. These potential co-management approaches represent agricultural and urban runoff, wastewater treatment plant effluent, and combined sewer overflow replacements. Twelve estrogenic compounds and their metabolites were analysed by gas chromatography-mass spectrometry. Estrogenic activity (E₂Eq) was measured by in vitro bioassay. We detected estrone E₁ (0.05-6.97 ng L^-1) and estriol E₃ (below detection-8.13 ng L^-1) and one conjugated estrogen (estrone-3-sulfate E₁-3S; below detection-8.13 ng L^-1). E₁ was widely distributed and positively correlated with E₂Eq, water temperature, and dissolved organic carbon (DOC). Among nonpoint sources, E₂Eq, and concentrations of E₁, soluble reactive phosphorus (SRP) and total dissolved nitrogen (TDN) decreased by 51-61%, 77-82%, 62-64%, 4-16% in restored urban and agricultural streams with best management practices (BMPs) relative to unrestored streams without BMPs. In a wastewater treatment plant (Blue Plains WWTP), >94% of E₁, E₁-3S, E₃, E₂Eq and TDN were removed while SRP increased by 305% during nitrification/denitrification as a part of advanced wastewater treatment. Consequently, E₁ and TDN concentrations in WWTP effluents were comparable or even lower than those observed in the receiving stream or river waters, and the effects of wastewater discharges on downstream E₁ and TDN concentrations were minor. Highest E₂Eq value and concentrations of E1, E3, and TDN were detected in combined sewer overflow (CSO). This study suggests that WWTP upgrades with biological nutrient removal, CSO management, and certain agricultural and urban BMPs for nutrient controls have the potential to remove estrogens from point and nonpoint sources along with other contaminants in streams and rivers.