Spatial distribution, temporal trends, and environmental fate of legacy contaminants in the cryosphere of Spitsbergen, Svalbard Islands

The Arctic cryosphere, particularly the glaciers of the Svalbard Archipelago, serves as both a repository and an indicator of persistent organic pollutants (POPs) contamination transported via long-range atmospheric pathways. This study provides a comprehensive analysis of polychlorinated biphenyls (PCBs), legacy pesticides (LPs), and current-use pesticides (CUPs) in seasonal snow and shallow ice cores. Samples were collected from three Spitsbergen glaciers (Austre Brøggerbreen, Midtre Lovénbreen, and Kongsvegen) during two consecutive spring campaigns (2022-2023). PCBs dominated the contaminant profile, with the highest contributions found in surface snow. Low-chlorinated congeners, such as PCB8 and PCB52, were the most prevalent, reflecting cold-climate transport and deposition dynamics. LPs exhibited greater variability, showing higher concentrations in ice cores (mean 92.2 ± 50.9 pg/L), suggesting persistence and preferential retention during snow metamorphism and meltwater infiltration. In contrast, CUPs were more abundant in snow (mean 120 ± 73.6 pg/L), highlighting their potential for seasonal leaching. While total contaminant concentrations revealed no significant interannual differences, spatial variability highlighted the influence of glacier topography and exposure to atmospheric sources. Finally, we combined surface mass balance data with our analytical results to provide an estimate of the annual contaminant release of PCBs, LPs, and CUPs from snow and ice melt at the investigated glacial sites. Despite limited spatial representation, our findings reveal how climate change and deglaciation could remobilize these legacy contaminants, posing under-investigated risks to the Arctic ecosystem. These findings emphasize the urgent need for more targeted sampling and monitoring for a deeper understanding of persistent pollution in polar regions.