Persistent Organic Pollutants in Snow: Scavenging, Aging, and Implications for Remote Ecosystems

Snow is an efficient scavenger of both gas-phase and particulate-phase persistent organic pollutants (POPs) and other anthropogenic semi-volatile organic compounds (SOCs). In addition, in some remote high elevation and high latitude ecosystems, snow is the predominant form of annual precipitation and the primary route of POP deposition to these ecosystems. Recent laboratory and field studies have begun to elucidate the mechanisms of POP scavenging from the atmosphere, the physical and chemical aging of POPs in annual snowpack, and the release of POPs from melting snowpack to the ecosystem. These recent results suggest that POP deposition to remote ecosystems can result in bioaccumulation in the aquatic food web and, in some ecosystems, the concentrations of POPs in fish exceed human and wildlife health criteria.