High temporal resolution pollen analysis: New insights into current-use pesticides distribution in agricultural...

Current-use pesticides (CUPs) disperse beyond treated areas, leading to unintended exposure of pollinators and other non-target organisms. Although this issue has received increasing attention, understanding how CUPs behave in agricultural landscapes remains challenging due to complex transport processes and limited field-based evidence on their movement over space and time. To address this gap, we used weekly pollen samples collected from five honeybee colonies over two growing seasons (2023-2024) in an intensively managed agricultural area to investigate the distribution of CUP residues in agricultural landscapes. Pollen was separated by plant species, allowing contamination patterns to be interpreted in relation to crop phenology, application timing, and weather conditions. Multiple CUPs were detected in pollen from both treated crops and untreated off-crop plants such as wildflowers, demonstrating substantial off-target drift. CUP residues persisted beyond intended application periods, with the neonicotinoid insecticide acetamiprid detected weeks after application. The fungicide cyprodinil reached up to 1025 μg/kg_dw and was detected at distances exceeding 800 m from treated fields, suggesting contributions from spray drift, volatilisation, and atmospheric transport. By integrating pollen residue data with detailed spatial application records, crop maps, and meteorological information, this study moves beyond simple residue detection to infer the environmental processes that influence pesticide distribution. Our findings highlight the importance of weather conditions and the spatial distribution of agricultural and surrounding non-crop areas in shaping exposure pathways. These findings provide a strong evidence base for refining pesticide risk assessments and demonstrate that current mitigation measures may be insufficient to prevent widespread off-target exposure.