Title:

Detection of pharmaceuticals in biofilm exposed to municipal effluents using UPLC-MS/MS

Abstract:

Wastewater treatment plants (WWTPs) release complex mixtures of contaminants along with effluents post treatment process, including multiple classes of pharmaceuticals. Organic contaminants like pharmaceuticals can accumulate in biota after entering aquatic systems exposed to WWTP effluents. Many studies on the accumulation of organic contaminants focus on higher order organisms rather than reservoirs at lower trophic levels. Biofilm is an important found source for primary consumers and represent a point of entry for contaminants into aquatic food webs. Previous research has demonstrated the bioaccumulation of pharmaceuticals in biofilm downstream of effluent discharge but is limited. The goal of this research was to quantify the concentrations of pharmaceutical compounds in biofilm upstream and downstream of WWTPs utilizing a simple extraction method. Biofilm samples were collected from nearshore rocks across 3 time points, at 4 WWTPs, during the summer of 2023. Extraction methods were based on a modified liquid-liquid extraction followed by analysis using ultra-performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS). One antidepressant (Venlafaxine) and its metabolite (O-desmethylvenlafaxine) were detected at higher concentrations at all downstream sites in two thirds of time points sampled. Total pharmaceutical concentrations were higher downstream than upstream at 75% of all sites sampled across all time points. Using a subset of known pharmaceutical contaminants, this research observed the potential for these compounds to accumulate in biofilm downstream of municipal WWTPs. This research adds more data on a potential route of exposure for other organisms and the overall fate of pharmaceuticals in aquatic ecosystems exposed to effluents.