Impact of wastewater treatment plants on pesticide contamination in the Yeongsan River basin and prioritization of pesticides in wastewater treatment plant effluents

Abstract

Pesticides are widely distributed in the environment, posing significant risks to aquatic organisms, which necessitates effective management. This study aimed to identify priority pesticides originating from wastewater treatment plant (WWTP) effluents that pose risks to aquatic environments. Herein, a year-long monitoring of pesticides was conducted across six sites in the Yeongsan River basin and three WWTP effluents. Hierarchical cluster analysis was used to evaluate WWTP effluents as potential sources of pesticide contamination in the aquatic environments and to identify pesticides likely originated from effluents. Additionally, an optimized risk quotient (RQf)-based risk assessment was performed on WWTP effluents to evaluate the adverse effects of pesticides when discharged into surface water. Of the 87 target pesticides, 55 were detected in surface waters and 59 in WWTP effluents, with concentrations generally higher in WWTP effluents. Pesticides were categorized into six clusters based on their spatiotemporal occurrence patterns. Thus, this study concluded that pesticides potentially derived from WWTP effluents and posing a significant risk to aquatic environments, such as metribuzin, 3-phenoxybenzoic acid, atrazine, and atrazine-2-hydroxy, should be prioritized for regulation in WWTP effluents. This study highlights the importance of prioritizing pesticides to provide effective pollution management strategies and improve water quality. © 2025 Elsevier B.V.