Dirty Dozen Pollutants Ride Again

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An icy prison in the arctic has held 12 toxic threats that society banned from use decades ago. But the ice is melting. Now Aldrin, Endrin, Mirex, and nine others will soon break free and the consequences may be deadly.

No, this is not a Michael Bay film.

It’s a warning from scientists studying the “Dirty Dozen” of persistent organic pollutants (POPs). Rain, snow and other weather phenomenon deposited the chemicals in the arctic ice decades ago, but as the polar ice melts, the Dirty Dozen may be released back into the environment, said researchers working for the Canadian federal agency, Environment Canada, in a study published in the journal Nature Climate Change.

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“A wide range of POPs have been re-mobilised into the Arctic atmosphere over the past two decades as a result of climate change,” said the study, according to an article by the AFP.

Arctic warming “could undermine global efforts to reduce environmental and human exposure to these toxic chemicals,” stated the study led by Jianmin Ma of Environment Canada.

The chemicals were banned in 2001 by the Stockholm Convention, because of their health risks for humans and other animals and because they don’t break down quickly in the environment.

Though the researchers found a gradual downward trend since the chemicals were banned, the computer simulation showed that melting ice could cause a small increase in the concentrations.

The Dirty Dozen are (from US POP Watch Website):

*Aldrin- Pesticide widely used on corn and cotton until 1970. EPA allowed its use for termites until the manufacturer canceled registration in 1987. Closely related to dieldrin.

*Chlordane – Pesticide on agricultural crops, lawns, and gardens and a fumigant for termite control. All uses were banned in the United States in 1988 but still produced for export.

*DDT – Pesticide still used for malaria control in the tropics. Banned for all but emergency uses in the United States in 1972.

*Dieldrin – Pesticide widely used on corn and cotton until 1970. EPA allowed its use for termites until manufacturer canceled registration in 1987. A breakdown product of aldrin.

*Endrin – Used as a pesticide to control insects, rodents, and birds. Not produced or sold for general use in the United States since 1986.

*Heptachlor – Insecticide in household and agricultural uses until 1988. Also a component and a breakdown product of chlordane.

*Hexachlorobenzene (HCH) – Pesticide and fungicide used on seeds, also an industrial byproduct. Not widely used in the United States since 1965.

*Mirex – Insecticide and flame retardant not used or manufactured in the United States since 1978.

*Toxaphene – Insecticide used primarily on cotton. Most uses in the U.S. were banned in 1982, and all uses in 1990.

*PCBs – Polychlorinated biphenyls, widely used in electrical equipment and other uses. Manufacture of PCBs banned in the United States in 1977.

*Polychlorinated Dioxin and Polychlorinated Furans – Two notorious classes of “unintentional” pollutants, they are byproducts of incineration and industrial processes. Regulated in the United States under air, water, food quality, occupational safety, waste, and other statutes.

A little can go a long way, since POPs don’t break down. Instead, they accumulate in animals as they go up the food chain.

The U.S. Agency for Toxic Substances and Disease Registry lists the effects of each chemical in their database. Aldrin and Dieldrin, for example, can cause convulsions, kidney damage, headaches, vomiting, and even death.

The Environment Canada researchers make their warning based on observations of the atmosphere and a computer simulation of the effects that climate change will have on the Arctic ice.

Researchers observed the amounts of three POPs, DDT, HCH, and chlordane, in the atmosphere. They monitored the chemicals from 1993 to 2009 at a station on Norway’s Svalbard Islands and at another in the Canadian Arctic.

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“The re-mobilisation of pollutants generated by our grandparents… are unwanted witnesses to our environmental past that now seem to be ‘coming in from the cold,’” said Dachs.

IMAGE: The first sign of the spring melt – a stream is seen flowing on the ice – Alaska, Tigvariak Island, North Slope (Wikimedia Commons).

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