Evidence for local sources and trophic biomagnification of bisphenols in the Arctic

The Arctic, though remote, is exceptionally vulnerable to chemical contaminants that threaten its fragile ecosystems. Bisphenols (BPs), a class of endocrine-disrupting chemicals used in plastics and resins, are now detected across the Arctic, but the risks posed by their many analogues are poorly understood. Most studies have focused on documenting their presence, leaving a critical gap in our understanding of whether these compounds bioaccumulate in Arctic food webs and to what extent local, within-Arctic pollution contributes to the overall burden. Here we show, through a comprehensive analysis of 32 BPs in 134 samples from a Norwegian Arctic food web, that multiple BP analogues not only bioaccumulate but also biomagnify from plankton up to polar bears. We found that 5,5'-(1-methylethylidene)bis [(1,1'-biphenyl)-2-ol] (BPPH) exhibited the highest trophic magnification factor (TMF = 2.3), and we documented total BP concentrations in polar bear tissues up to 1396 ng g^-1 wet weight, orders of magnitude higher than in lower-trophic-level species. Furthermore, our analysis identified distinct local pollution sources, such as a firefighting training site releasing 2,4,6-trichlorophenol (2,4,6-TBP) and landfill leachate contributing other BPs to the local environment. These findings provide the first evidence of trophic magnification for multiple BPs in a polar food chain and underscore the urgent need to incorporate food-web dynamics and local source management into ecological risk assessments for the Arctic.