Quaternary ammonium compounds (QACs) are a group of chemicals used in a wide range of consumer and industrial products including disinfectants. Due to the COVID-19 pandemic, use of disinfectants has increased significantly since March 2020, increasing loads to wastewater plants and the environment. QACs have been shown to impact the development of antibiotic resistance and may be toxic to aquatic life; therefore, it is important to study the increasing use of disinfectants in the environment and determine if they are being successfully removed during treatment. Approximately 90% of QACs are removed during wastewater treatment, but these are high production volume chemicals and therefore a significant amount still could be getting released into the environment. In addition, increased loads to treatment plants might impact the effectiveness of removal. Monthly effluent and influent wastewater samples have been collected from 10 different plants around Minneapolis, Minnesota and 3 plants in San Francisco, California since May 2020. These samples are being analyzed for 20+ quaternary ammonium compounds including benzylalkonium compounds (BACs), alkyltrimethylammonium compounds (ATMACs), dialkyldimethylammonium compounds (DADMACs) and ethylbenzylammonium compounds (EtBACs) using solid phase extraction and analysis by LC-MS/MS. Results show that there is a substantially higher concentration of QACs in the influent than in the effluent, with some total concentrations on the order of micrograms per liter. For effluents, QACs were observed in many samples, mostly with concentrations in the nanogram per liter range. BACs comprise the highest concentration of analytes of interest, as expected, for these are the most widely used QACs. This data is compared to a previous study of QACs in Minnesota wastewater effluent conducted pre-pandemic to see if there is a noticeable increase as hypothesized.

Investigating the increase in quaternary ammonium compounds in wastewater and the environment due to the COVID-19 pandemic

ACS Spring 2022

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