Keywords
Municipal Wastewater Treatment Plant Effluent (WWTP); Chemicals of Emerging Concern (CECs); Hormones; Yeast Estrogen Screen (YES); Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS).
Abstract
Contaminants of emerging concern (CEC) are known to affect aquatic organisms downstream of wastewater treatment plant effluent discharges. Studies in the Grand River watershed on the small-bodied, benthic rainbow darter (Etheostoma caeruleum) have shown altered gene expression, sex steroid levels, gonad size and expression of intersex (testis-ova) associated with wastewater outfalls. Due to these observed biological impacts, over $450M has been spent by the municipal government to upgrade the two major wastewater treatment plants (WWTP) within the Grand River watershed (Waterloo, Kitchener). In this study we monitored process upgrades at each of the WWTPs between 2010 to 2019 for a suite of chemicals including nutrients, CECs, hormones and total estrogenicity. Effluent samples for select CECs and total estrogenicity were analyzed by LC-MS/MS and yeast estrogen screen (YES) assay, respectively. Estrogenicity of the effluent declined rapidly after upgrades were completed. The removal of key CECs varied depending on their physiochemical properties. Although treatment process upgrades lead to greatly reduced environmental exposure to many CECs such as naproxen, some remain at relatively high concentrations (i. e. carbamazepine) that may continue to represent a risk to the environment.
Citation
Srikanthan N, Fattahi A,McCann EK, Bragg LM, Dhiyebi H, et al. (2025) Evaluating Changes in Contaminants of Emerging Concern in Municipal Wastewater Ef