Interpreting the unheeded inherent connections between micropollutants: PFAS and Pesticides

The widespread contamination of the environment by fluorinated compounds, particularly those categorized as per- and polyfluoroalkyl substances (PFAS), has emerged as a pressing global issue. These substances have well-documented adverse effects on human health, biodiversity, and overall ecosystem stability. Recent scientific investigations have identified PFAS-class chemicals in pesticide formulations, including within the active ingredients of these products. Considering the wide range of health effects associated with PFAS exposure, it is critical to investigate how the presence of carbon-fluorine bonds within pesticide ingredients contributes to their environmental persistence and toxicity. Therefore, this study aims to unravel the interactions among PFAS and pesticides, in particular, offering insights into their combined effects on the ecosystem and organismal health. Surface water (SW) and groundwater (GW) samples were collected from various sites across Yorkshire County, England, in 2023. The concentrations of total PFAS and pesticides in SW ranged from <0.00009 to 0.0531 μg L^-1 and <0.0001 to 0.04 μg L^-1, respectively. Among PFAS and pesticide compounds analyzed, perfluorooctane sulfonic acid (PFOS), Endrin, and Permethrin exhibited the highest concentrations in SW. Conversely, GW samples demonstrated relatively lower concentrations of all compounds, except Atrazine, Endosulfan, and Aldicarb, which were detected at elevated levels. Correlation analysis revealed moderate to weak relationships between PFAS and pesticides, with comparatively stronger correlations observed between DDT and perfluorooctanoic acid (PFOA), perfluorooctanoic acid (PFPeA), and perfluorohexanoic acid (PFHxA). These correlations likely stem from the inherent persistence, mobility, and water solubility of these substances. Furthermore, strong correlations among pesticides such as Endosulfan, DDT, Aldrin, and Malathion were identified, likely reflecting shared chemical behaviors and historical usage patterns in pest control practices. Therefore, the result from this study constitutes a pioneering exploration of the potential interactions between PFAS and pesticides, underscoring the critical need for further research to assess their toxicity comprehensively.

Keywords: PFAS; pesticides; interactions; UK; groundwater; PFOS; toxicity; surface water.