Bridging ecosystem and human health: distinct neonicotinoids accumulation drivers and human exposure pathways in a...

Multifunctional reservoirs are critical environmental nexus points under constant threat from chemical contamination. In this study, the risks of neonicotinoid insecticides (NEOs) were investigated from a "One Health" perspective, linking agricultural pollution to human exposure via drinking water and fish consumption. Widespread contamination was confirmed across the water-sediment-fish system, with spatiotemporal dynamics mechanistically linked to compound-specific properties and seasonal agricultural inputs. Significant ecological risks were quantified (max ΣRQ = 18.77 in environmental media, max ΣRQ = 33.4 in fish), peaking in an agricultural tributary hotspot and wild catfish (Silurus glanis). A probabilistic human health risk assessment confirmed drinking water as the predominant exposure pathway, identifying children as the most vulnerable group. Crucially, advanced Piecewise SEM modeling delineated fundamentally divergent bioaccumulation drivers: accumulation in wild fish was governed by aqueous concentrations, whereas farmed fish exposure was dominated by Water Temperature and external, unmodeled inputs (commercial feed). This mechanistic divergence offers a refined, target-specific predictive tool for risk management. The findings provide a critical scientific basis for the implementation of season-specific monitoring and source regulation to protect both human health and vital ecosystem services.