Polychlorinated Biphenyl Contamination of Freshwater Fish From Military Sites in the Aleutian and Bering Sea Islands Region

Abstract

The biomagnification of persistent organic pollutants (POPs) in the arctic foodweb is a key concern of the Aleutian and Bering Sea Islands (ABSI) Initiative, a partnership dedicated to tackling the “unprecedented environmental change impacting the lives, lands, and waters” of the ABSI region. To address this concern, this thesis expands upon the current but limited knowledge of regional pollution of a signature POP, polychlorinated biphenyls (PCBs). PCBs are considered “probable human carcinogens” by the US Environmental Protection Agency (EPA)2. They are also associated with adverse neurological, reproductive, and immune system effects in animals. Through the process of global distillation, the Arctic serves as a hemispheric sink for PCBs used and manufactured at lower latitudes. Once in the Arctic, PCBs bioaccumulate and biomagnify in the lipid-rich arctic foodweb. Due to both global distillation and local sources of pollution such as military sites, arctic Indigenous people practicing a subsistence lifestyle are exposed to high levels of PCBs. Despite the ecological, cultural, and economic significance of the ABSI region, as well as regional reliance on a subsistence diet, little information exists on current and long-term regional trends in PCB contamination of important biota. The ABSI region was militarized during World War II and the Cold War. As a result of militarization, 51 formerly used defense (FUD) sites are scattered across 32 islands. FUD sites are known hotspots for POPs including PCBs, but the majority have not seen any remediation. The United Nation’s 2020 Arctic Monitoring and Assessment Programme report suggests that while atmospheric deposition of PCBs in arctic environments is decreasing, re-emissions from local sources, such as military sites, are becoming increasingly important. Little is known about the importance of FUD sites as sources of PCB contamination in the ABSI region. Identifying trends in long-range PCB contamination, as well as the role FUD sites play in local contamination, is vital to protecting the unique ecosystems and subsistence practices of the region. As such, the aims of this thesis are to: 1) provide a background and historical information on the Arctic and the ABSI region as it relates to PCB pollution; and 2) analyze PCB contamination in two freshwater fish species collected military and non-military sites throughout the ABSI region. Future work will include an examination of PCB contamination of fish and shellfish on Unalaska Island and a quantitative risk assessment based on contaminant concentrations in fish.