Contamination assessment and risk evaluation of organophosphorus pesticides in groundwater: A study on contamination patterns and implications

Groundwater contamination by organophosphorus pesticides (OPPs) poses a serious environmental and public health threat, particularly in regions with intensive agricultural activity. While previous studies have focused on pesticide contamination in surface water, there is a lack of comprehensive data on OPP concentrations in groundwater and their associated health risks. This study addresses this gap by analyzing the occurrence, spatial distribution, and health risks of ten OPPs in 1168 groundwater samples from the Campania Plain, Southern Italy. The results revealed contamination hotspots in Caserta, Naples, and Salerno, with mean total OPP concentrations of 26.4, 26.0, and 24.9 ng/L, respectively. Dimethoate (13.5 %), chlorpyrifos (17.8 %), and parathion (13.0 %) were the most frequently detected pesticides, with chlorpyrifos persisting despite its EU ban in 2020. A human health risk assessment indicated that while non-carcinogenic risks (Hazard Index = 0.634) were below safety thresholds, carcinogenic risks exceeded acceptable limits for children, particularly for dichlorvos (4.26 × 10⁻³) and dimethoate (5.89 × 10⁻³). Statistical analysis, including Principal Component Analysis (PCA), revealed significant correlations between pesticide distribution and land use, emphasizing the role of intensive agriculture in groundwater contamination. This study highlights the urgent need for stricter regulations, improved groundwater monitoring, and sustainable pesticide management practices to mitigate health risks and protect water resources.