Thursday, August 11, 2022

A New Antarctica study shows that levels of toxic chemicals increased markedly

Levels of ‘forever chemicals’ reaching the remote continent have been increasing.

Perfluoroalkyl acids (PFAAs) are synthetic chemicals with various industrial and consumer applications that are now widely distributed globally. Also known as toxic ‘fluorinated forever chemicals,’ these chemicals do not break down naturally in the environment.

A new study offers evidence that the levels of ‘forever chemicals’ have increased markedly in the remote environment of Antarctica in recent decades. According to scientists, CFC replacements could be among the likely sources.

Scientists, for this study, collected firn (compacted snow) cores from the extremely remote, high, and icy Dronning Maud Land plateau of eastern Antarctica. Snow accumulation of the extracted core dated from 1958 to 2017. Scientists observed increasing PFCA accumulation in snow over this time period. Perfluorooctanoic acid (PFBA) was the most abundant chemical discovered by far. It is to be noted that the concentrations of these chemicals in snow cores increased significantly from around the year 2000 until the core was taken in 2017.

The study was led by scientists from Lancaster University along with researchers from the British Antarctic Survey and the Hereon Institute of Coastal Environmental Chemistry, Germany.

Professor Crispin Halsall of Lancaster University, who led the study, believes this increase can be partly explained by a switch by global chemicals manufacturers around 20 years ago from producing long-chain chemicals like PFOA to shorter-chain compounds such as PFBA due to health concerns associated with human exposure to PFOA.

Dr. Jack Garnett, who conducted the chemical analysis on the snow samples, added: “The significant increase in PFBA observed from the core, particularly over the last decade, suggests there is an additional global source of this chemical other than polymer production. We know that some of the chemicals replacing the older ozone-depleting substances like CFCs and HCFCs, such as the hydrofluoroethers, are produced in high quantities as refrigerants but can break down in the atmosphere to form PFBA.”

“The Montreal Protocol certainly provided huge benefits and protection to the ozone, the climate, and us all. However, some of these replacement chemicals’ wider environmental and toxicity impact is still unknown.”

From the mid-1980s onward, the abundance of PFOA was increasing with no evidence of a decline in more recent years to match the global industry phase-out of this chemical. This indicates that production of PFOA was maintained or that volatile precursors to this chemical have remained high in the global 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, holds this next signal of human activity arising from emissions thousands of miles away. The snow and ice of Antarctica are critical archives of our changing impact on our planet.”

According to scientists, the chemicals are most likely getting to Antarctica through industrial manufacturing sites that discharge volatile “precursor” chemicals into the atmosphere. These precursors waft in the global atmosphere until they eventually degrade in the presence of sunlight to form the more persistent PFCAs.

Successive snowfall over the years has deposited these chemicals from the atmosphere resulting in a historical record of global contamination that is now trapped in the snowpack.

The findings, which are in line with modeled estimates of PFCA chemical emissions, add to the mounting evidence that these pollutants are increasing in the Arctic and on the Tibetan Plateau. They also help paint a complete picture and deepen our understanding of how pollutants like these are transported through the atmosphere.

Dr. Markus Frey, a scientist from the British Antarctic Survey and co-author of the report, said: “This is another example that despite its extreme remoteness, man-made pollution does reach the Antarctic continent and is then archived in snow and ice, which allows us to establish a history of global atmospheric pollution and effectiveness of mitigation measures.”

Dr. Markus Frey, the scientist from the British Antarctic Survey and co-author of the report, said“This is another example that despite its extreme remoteness, man-made pollution does reach the Antarctic continent and is then archived in snow and ice, which allows us to establish a history of global atmospheric pollution and effectiveness of mitigation measures.”

Journal Reference:

  1. Jack Garnett, Crispin Halsall, et al. Increasing Accumulation of Perfluorocarboxylate Contaminants Revealed in an Antarctic Firn Core (1958–2017). Environ. Sci. Technol. 2022. DOI: 10.1021/acs.est.2c02592
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