Melting Arctic ice releasing banned toxins, warn scientists
Unknown amount of trapped persistent organic pollutants poses threat to marine life and humans as temperatures rise
Melting Arctic ice is allowing chemicals to seep out, including the pesticides DDT, lindane and chlordane, as well as PCBs. Photograph
The warming of the Arctic is releasing a new wave of banned toxic chemicals that had been trapped in the ice and cold water, scientists have discovered.
The researchers warn that the amount of the poisons stockpiled in the polar region is unknown and their release could "undermine global efforts to reduce environmental and human exposure to them."
The chemicals seeping out as temperatures rise include the pesticides DDT, lindane and chlordane, made infamous in Rachel Carson's 1962 book Silent Spring, as well as the industrial chemicals PCBs and the fungicide hexachlorobenzine (HCB). All of these persistent organic pollutants (Pops) are banned under the 2004 Stockholm Convention.
Pops can cause cancers and birth defects and take a very long time to degrade, meaning they can be transported for long distances and accumulate over time. Over past decades, the low temperatures in the
But scientists in
After allowing for the decline in global emissions of Pops, the team showed that the toxic chemicals are being remobilised by rising temperatures and the retreat of the sea ice, which exposes more water to the Sun. For example, air concentrations of PCBs and HCBs have shown a rising trend from about 2004 onwards. Their work is published in the journal Nature Climate Change.
Hayley Hung, a member of the air quality research division of Environment Canada and of the team, said its work provided the first evidence of the remobilisation of Pops in the
Hung said that, with the exception of lindane, there was little existing knowledge of the scale of the Pops stored in high latitude regions
The fate of the frozen Pops depends on the speed of warming in the
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