Ice samples from both sides of the Himalayan mountain range have revealed that the level of toxic pollution in the environment is falling. According to a research paper in the leading American Chemical Society journal, Environmental Science & Technology, analysis of ice cores extracted from the eastern and western ends of The Tibetean Plateau reveal fascinating results reflecting a change in the world’s production practices.
In a joint project with scientists from Lancaster University and colleagues from China and Germany, samples taken over 30 years from the ice cores showed how residues of Perfluoroalkyl substances (PFASs) in the environment are changing. “PFASs are used in many everyday products such as fabric linings, non-stick pans and firefighting foams,” said Dr Crispin Halsall of Lancaster University’s Environment Centre, adding: “These chemical residues are carried thousands of miles on the prevailing winds and deposited in the ice.”
The results revealed that on the western side of the Plateau where the prevailing wind comes from Europe, PFASs initially increased in the 1980s and then decreased as industrial output changed in the early 2000s thanks to measures implemented to help the environment. On the eastern side, where the prevailing wind comes from Asia, the level of residues is still increasing as this continent becomes more industrialised, but the nature of the PFASs is less toxic.
Dr Halsall explained: “Long carbon chain compounds are particularly toxic and businesses have responded by producing shorter chain compounds and we are starting to see that in the ice cores.” He concluded: “It provides the evidence that you can change things and reduce the prevalence of toxic chemicals through consensus and an international framework. That is very encouraging.”