Decoding PFAS-pesticide co-occurrences: Spatial hotspots, mixture patterns and multivariate drivers in Yorkshire Waters, United Kingdom
Academic Article in Scopus
Mixtures of per- and polyfluoroalkyl substances (PFAS), legacy pesticides, and metals are increasingly detected in freshwater system, yet joint occurrence patterns and spatial dynamics across connected surface¿groundwater domains remain underexplored. Here we compile monitoring data from Yorkshire, United Kingdom, to quantify the co-occurrence of PFAS, selected pesticides, and metals in rivers and aquifers, map spatial hotspots, and identify physicochemical drivers. We harmonized datasets, applied inverse-distance weighting to visualize concentration fields, and used correlation analysis, principal component analysis, and hierarchical clustering to resolve mixture structure and source signals. We benchmarked observations against relevant UK/EU/WHO guideline values to contextualize potential compliance concerns. Results reveal distinct mixture fingerprints between surface water and groundwater, short-chain PFAS prominence in groundwater, and localized pesticide hotspots consistent with historical and agricultural use. Multivariate patterns suggest hydrogeochemical controls (e.g., pH, redox) modulate PFAS¿pesticide associations, with several clusters co-occurring near urbanagricultural interfaces. We discuss implications for monitoring design, treatment prioritization, and targeted risk management. By integrating spatial interpolation with mixture-aware statistics across media, this study provides actionable evidence to focus surveillance on high-risk analytes and locations in temperate catchments.
