New data from Antarctica shows that the amount of toxic “fluorinated chemicals forever” has increased markedly in the remote environment in recent decades, and scientists suggest that CFC substitutes may be one likely source.
Chemicals such as perfluorocarbons (PFCAs), known as timeless chemicals because they do not break down naturally in the environment, have a wide range of applications, such as non-stick pan coatings, water repellents for clothing and fire retardants. combat foams. One of these chemicals, perfluorooctanoic acid (PFOA), bioaccumulates in food webs and is toxic to humans, leading to impaired immune systems and infertility.
In this new study, published in the journal Environmental sciences and technologiesled by scientists from Lancaster University, together with researchers from the British Antarctic Survey and the Institute of Coastal Environmental Chemistry, Heeron, Germany, cores of firn (compacted snow) were taken from the very remote, high and icy Dranning Maud Earth Plateau in East Antarctica. .
The cores, which provide a historical record between 1957 and 2017, provide evidence that levels of these chemical pollutants have shown a marked increase in the remote Antarctic snowpack over the past few decades.
The most common chemical found to date was a shorter-chain compound, perfluorobutanoic acid (PFBA). Concentrations of this chemical in snow cores increased significantly from around 2000 to when the core was taken in 2017.
Professor Crispin Halsall of Lancaster University, who led the research, believes the rise can be partly explained by a shift by global chemical manufacturers around 20 years ago from producing long-chain chemicals such as PFOA to shorter-chain compounds such as PFBA due to health concerns related to human exposure to PFOA.
Dr Jack Garnett, who carried out the chemical analysis of the snow samples, added: ‘The large increase in PFBA observed in the core, particularly over the last decade, suggests that there is an additional global source of this chemical beyond polymer production. We know that some of the chemicals that replace the old ozone-depleting substances, such as CFCs and HCFCs, such as hydrofluoroethers, are produced worldwide in large quantities as refrigerants, but can break down in the atmosphere to form PFBAs.
“The Montreal Protocol has certainly brought enormous benefits and protections to the ozone, the climate and all of us. However, the wider environmental impact and toxicity of some of these substitute chemicals is still unknown.’
PFOA shows a snowball increase from the mid-1980s onward, but with no evidence of a decline in recent years to match the global industry’s phase-out of the chemical. This suggests that production of PFOA has continued or that volatile precursors of the chemical remain high in the global atmosphere.
The researchers behind the study believe the chemicals are most likely reaching Antarctica through the release of volatile precursor chemicals into the atmosphere at industrial production sites. These precursors float in the global atmosphere until they are eventually degraded by sunlight to form the more persistent PFCAs.
Successive snowfalls over the years have washed these chemicals out of the atmosphere, resulting in a historic record of global pollution that is now trapped in the snowpack.
The results, which match the simulated estimates of PFCA chemical emissions, further add to the evidence showing increases in these perennial chemicals in the Arctic and the Tibetan Plateau, and help provide a global picture and further understanding of how such chemicals are transported into the atmosphere.
Dr Anna Jones, director of science at the British Antarctic Survey, said: “These findings are a sobering reminder that our industrial activities have global consequences. Antarctica, so remote from industrial processes, contains the next signal of human activity resulting from emitted thousands of miles. The snow and ice of Antarctica are important archives of our changing impact on our planet.”
Dr Marcus Frey, a scientist with the British Antarctic Survey and a co-author of the report, said: “This is another example of how, despite the extreme remoteness, anthropogenic pollution does reach the Antarctic continent and is then stored in snow and ice, allowing us to create the history of global air pollution and the effectiveness of mitigation measures’.