El calentamiento global libera nuestros venenos a la atmósfera


26-07-2011

El retroceso del hielo en el Ártico a consecuencia del cambio climático está produciendo un aumento de las concentraciones atmosféricas de los pesticidas y otros contaminantes orgánicos persistentes (POPs), como los PCB, HCB o DDT, que hasta ahora se habían ido almacenando en el hielo y los suelos del Ártico. Parece ser que el deshielo provocado por el calentamiento global está dando lugar a la liberación a la atmósfera de mayores cantidades de estas sustancias tóxicas, según un estudio realizado por investigadores de Canadá y Noruega, que analizaron los cambios en los niveles de concentración en el aire del Ártico de varios POPs en dos estaciones situadas en el norte de Canadá y en el archipiélago noruego de Svalbard, entre 1993 y 2009. A la luz de los resultados, los científicos advierten de los obstáculos que el cambio climático está provocando en este sentido respecto a los esfuerzos realizados para reducir el uso de estas sustancias tóxicas desde 20 04, con la entrada en vigor del Convenio de Estocolmo. El informe ha sido publicado en la revista Nature.
> http://www.nature.com

Revolatilization of persistent organic pollutants in the Arctic induced by climate change

Jianmin Ma,     Hayley Hung,     Chongguo Tian     & Roland Kallenborn
Nature Climate Chang
Received 29 March 2011 Accepted 21 June 2011 Published online 24 July 2011

Persistent organic pollutants (POPs) are organic compounds produced by human activities that are resistant to environmental degradation. They include industrial chemicals, such as polychlorinated biphenyls, and pesticides, such as dichlorodiphenyltrichloroethane.

Owing to their persistence in the environment, POPs are transported long distances in the atmosphere, accumulating in regions such as the Arctic, where low temperatures induce their deposition1, 2.

Here the compounds accumulate in wildlife and humans, putting their health at risk1, 3, 4.

The concentrations of many POPs have decreased in Arctic air over the past few decades owing to restrictions on their production and use. As the climate warms, however, POPs deposited in sinks such as water and ice are expected to revolatilize into the atmosphere5, and there is evidence that this process may have already begun for volatile compounds6.

Here we show that many POPs, including those with lower volatilities, are being remobilized into the air from repositories in the Arctic region as a result of sea-ice retreat and rising temperatures. We analysed records of the concentrations of POPs in Arctic air since the early 1990s and compared the results with model simulations of the effect of climate change on their atmospheric abundances. Our results indicate that a wide range of POPs have been remobilized into the Arctic atmosphere over the past two decades as a result of climate change, confirming that Arctic warming could undermine global efforts to reduce environmental and human exposure to these toxic chemicals.

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