Bad hair and shoulder pads are not the only things from the 1980s that we'd rather not see again. Nasty chemicals banned in that decade are also on the list. Unfortunately, melting Alpine glaciers are generating a revival of toxic organic pollutants.

Christian Bogdal and colleagues at the Swiss Federal Institute of Technology in Zurich studied levels of pollution in sediment at the bottom of the Oberaar lake in Bern, Switzerland.

The flow of pollutants into the lake peaked in the 1970s, mainly due to the production of plastics, electronics, pesticides and fragrances. The levels declined during the 1980s and 1990s when people realised that these compounds were toxic and they were banned.

However, they found that banned chemicals, such as pesticides that have been linked with Parkinson's disease, have been pouring into the lake at an increasing rate since the 1990s.

Bogdal reckons that a glacier feeding the lake has been storing these chemicals for decades, and is releasing them as it melts. This process could be dramatically sped up by global warming, he warns.

The problem isn't limited to Alpine glaciers. Since these chemicals would have been transported great distances via the atmosphere before they were frozen into ice, many other glaciers around the world may be contaminated. Toxic chemicals have previously been found in polar regions - putting arctic wildlife at risk.

There is little we can do about it, however. "Stopping global warming could slow the melting of glaciers, but the chemicals will still be released eventually," says Bogdal.

Many toxic chemicals are still used in plastics and electronic equipment, such as brominated flame retardants. Bogdal warns that these could represent the next generation's problem: "They are deposited on glaciers today and will reappear in our lakes in a few decades."

Journal reference: Environmental Science & Technology, DOI: 10.1021/es901628x

Link:  http://www.newscientist.com/article/dn17956-melting-glaciers-bring-1980s-pollution-revival.html