Bioaccumulation and Biomagnification in Arctic Food Webs

The Arctic marine environment is vulnerable to accumulation of toxic contaminants due to atmospheric and oceanic long-range transport and biodegradation resistance. Persistent organic pollutants (POPs) like polychlorinated biphenyls (PCBs), brominated flame retardants, and certain pesticides bioaccumulate and biomagnify in Arctic marine food webs. Their lipophilic nature causes them to concentrate in fatty tissues of organisms. Some currently used chemicals that are not yet regulated as POPs, like certain polyfluorinated substances, are also being detected in the Arctic. Metals like mercury, cadmium, and lead reach the Arctic through atmospheric transport of particulates from industrial activities at lower latitudes. In the Arctic, these metals deposit and enter marine food webs through bioaccumulation in plankton and fish. Methylmercury, an organic form that bioaccumulates to a greater degree, is produced by natural processes, but its formation is enhanced by human activities. Indigenous Arctic populations are exposed to accumulated toxicants through their reliance on traditional foods like marine mammals and fish, raising public health concerns. Monitoring programs have revealed temporal trends and hot spots of contamination. As sea ice melts due to climate change, there are concerns about remobilization of pollutants accumulated in multiyear sea ice as well as increased maritime activities contributing additional contaminants.