Persistent Organic Pollutants in Alaska
Contaminants in Alaska
Persistent organic pollutants (POPs) are a group of chemicals which are defined by certain shared key characteristics. They are man-made organic compounds and highly toxic. They persist in the environment, and bioaccumulate in living organisms, often preferentially in the lipid, or fatty, tissues. They are able to travel long distances around the globe, due in part to their tendency to degrade very slowly, and in part to their ability to evaporate and recondense (called volatilization and revolatilization, or global distillation)—sometimes in repeated cycles—as they travel to the polar regions.
POPs migrate to northern climates because of strong south-to-north air flows, which transport contaminants from lower latitudes. Most POPs are industrial chemicals or pesticides that were invented for specific uses, but some, such as the dioxins and furans, are by-products of industrial and incineration activities in which chlorinated chemicals are significant constituents. Twelve POPs have been identified as targets for early global action in the POPs Treaty negotiations that were under the aegis of the United Nations Environment Programme (UNEP): aldrin, dieldrin, endrin, chlordane, DDT, heptachlor, mirex, toxaphene, hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (dioxin), and polychlorinated furans (furans). Also included was hexachlorocyclohexane (HCH), whose gamma (g) isomer is familiar to many people as the pesticide lindane used for head lice. HCH, while not on the current UNEP POPs list, is widely considered a significant Arctic contaminant.
POPs migrate to northern climates because of strong south-to-north air flows, which transport contaminants from lower latitudes. Most POPs are industrial chemicals or pesticides that were invented for specific uses, but some, such as the dioxins and furans, are by-products of industrial and incineration activities in which chlorinated chemicals are significant constituents. Twelve POPs have been identified as targets for early global action in the POPs Treaty negotiations that were under the aegis of the United Nations Environment Programme (UNEP): aldrin, dieldrin, endrin, chlordane, DDT, heptachlor, mirex, toxaphene, hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (dioxin), and polychlorinated furans (furans). Also included was hexachlorocyclohexane (HCH), whose gamma (g) isomer is familiar to many people as the pesticide lindane used for head lice. HCH, while not on the current UNEP POPs list, is widely considered a significant Arctic contaminant.