Estrogens, steroid hormones excreted by vertebrates, are potent endocrine-disrupting compounds which are classified as contaminants of emerging concern. They are primarily introduced to the environment by raw and treated sewage. Research previously focused on free estrogens, but other forms are also prevalent: conjugates (glucuronide and sulfate; naturally excreted) and halogenated estrogens (addition of one or two chlorines or bromines; formed during wastewater treatment). Effluent samples were collected at the Willow Lake Pollution Control Facility in Salem, OR (April 2016, June 2016, July 2016, March 2017). Solid phase extraction followed by liquid chromatography coupled with a triple quadrupole mass spectrometer (AB Sciex QTRAP4000) were used to analyze the estrogens. Total estrogen in E2 equivalents ranged from 26.05 ng/L (June) to 292.55 ng/L (March). In general, the halogenated and conjugated forms dominate ng/L concentrations during wet season months. Free estrogens dominate ng/L concentrations in the dry season. Halogenated and free forms were present at higher concentrations than conjugated estrogens in all seasons. The distribution of halogenated estrogens in particular is affected by several factors. Chlorinated forms, generated during chlorine-based treatment of wastewater, are present in concentrations 1.4–3.4 times that of brominated forms, with the monochloro form dominating. These forms are especially prevalent in times of high flow and wet weather. We hypothesize that this is due to inefficient removal during secondary treatment and slower photochemical degradation in the disinfection basin.

Quantification and comparison of free, conjugated, and halogenated estrogens in effluent from several wastewater treatment plants in northwestern Oregon

255th National Meeting (2018)

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