Estrogenic Activity of Wastewater at Different Stages in Three Activated Sludge Municipal Wastewater Treatment Plants in Central Tennessee

Abstract

It is known that endocrine disrupting compounds can be found in the effluent of wastewater treatment plants. Included in this category are estrogens and estrogenic chemicals. When effluent from wastewater treatment plants enters aquatic systems, estrogens in the effluent can have a negative effect on the development and reproductive system of organisms found there. Many studies have demonstrated these effects in fish and mollusks. These estrogenic compounds are found in the effluent because wastewater treatment plants are not designed to break down pharmaceutical or hormonal compounds. The aim of the present study was to follow estrogenic activity through three similar wastewater treatment plants in Central Tennessee. Water samples were taken from each plant’s influent and effluent, as well as from the oxidation ditch where the activated sludge process occurs and from water that had yet to be disinfected with ultraviolet radiation. These water samples were examined for estrogenic activity using a bioluminescent yeast estrogen screen (BLYES) assay and liquid chromatography-mass spectrometry (LC-MS). Estrogenic activity was then compared along points in the treatment process for each of the wastewater treatment plants to determine if there is a particular step in the process that significantly decreases estrogenic activity. There was no significant difference (F(3,11) = 2.87, p = 0.104) of estrogenic activity among points in the treatment process, nor was there a significant difference (F(3,11) = 2.12, p = 0.176) in individual estrogenic compound concentrations among treatment points. However, there does seem to be a general trend of decreasing estrogenic activity and concentration from influent to effluent.