Polychlorinated biphenyl (PCB) contamination of subsistence species on Unalaska Island in the Aleutian Archipelago

Polychlorinated biphenyls (PCBs) are a group of synthetic, lipophilic organochlorines that were banned due to their impacts on human and wildlife health and environmental persistence. Although banned, the continued release from pre-banned products allows them to persist at toxic levels in the environment. This is especially the case in lipid rich food webs of the Arctic, where PCBs accumulate due to both long-range atmospheric transport and locally contaminated sites such as formerly used defense (FUD) sites. At the request of the leadership of the Qawalangin Tribe of Unalaska Island in the Aleutian Archipelago, we analyzed PCB concentrations in samples of threespine stickleback (Gasterosteus aculeatus) and subsistence foods (i.e., salmonid species and blue mussels [Mytilus edulis]) collected at both FUD and non-FUD sites. PCBs were extracted from samples using a QuEChERS method. The mean PCB concentrations across all mussel samples was 6.1 ppb; mussels from FUD sites had nearly double the PCB concentrations (7.6 ppb) compared to non-military sites (3.9 ppb), and at two FUD sites the PCB concentrations exceeded safe consumption guidelines. The mean total PCB concentration for fish was 2.8 ppb; fish PCB concentrations were higher at FUD sites (3.2 ppb) compared to non-military sites (1.2 ppb). These results support the need to remediate the FUD sites of "Building 551/T Dock to Airport" and "Delta Western". More generally, these results provide further evidence of the continued problem of PCB contamination at FUD sites in the Arctic, many of which are co-located with indigenous communities.