Story at a glance
- Despite the widespread proliferation of per- and polyfluoroalkyl substances (PFAS) in populated areas, new research documents rising levels of these “forever chemicals” in remote regions of Antarctica.
- Researchers theorize the chemicals are wafted into the atmosphere, broken down and then deposited into the Antarctic snow.
- Samples dating back to 1957 show increasing levels of PFAS over decades, while some show no signs of abating.
Detection of certain per- and polyfluoroalkyl substances (PFAS) in U.S. drinking water has prompted action from regulatory and health agencies alike, given the harmful health effects associated with some of these chemicals.
The widespread proliferation and persistent nature of these chemicals also poses threats to the natural environment, and new research out of Lancaster University in England details rising levels of PFAS detected in remote Antartic regions.
PFAS do not naturally break down over time due to their strong carbon and fluorine bonds, earning them the nickname “forever chemicals.” PFAS can be found in consumer products ranging from makeup to cookware, in addition to pollution from companies who use the chemicals to manufacture products.
Although regulations aimed at phasing out certain PFAS (PFOA and PFOS) in the United States went into effect in 2016, these actions did not address the large quantities of chemicals already in products sold before the ban or those imported from other countries.
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To better understand any changes in PFAS levels detected in the natural environment, investigators measured six perfluorocarboxylates (PFCA, C4–C9) from a site in Dronning Maud Land in Eastern Antarctica.
Firn, or compacted snow cores, dating from 1957 to 2017 were collected and assessed for the chemicals.
“We observed increasing PFCA accumulation in snow over this time period, with chemical fluxes peaking in 2009–2013 for PFOA, C8 and nonanoate (PFNA, C9) with little evidence of a decline in these chemicals,” authors wrote.
“The levels of perfluorobutanoate (PFBA, C4) increased markedly since 2000, with the highest fluxes in the uppermost snow layers,” they continued.
PFBA was also the most abundant chemical detected in the samples. Researchers hyopthesized the rising levels of PFAS seen could be partially due to the replacement of long-chain chemicals like PFOA to shorter-chain compounds like PFBA.
“The large 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,” said co-author Jack Garnett of Lancaster University in a statement.
“We do know that some of the chemicals replacing the older ozone-depleting substances like [chlorofluorocarbons] and [hydrochlorofluorocarbons], such as the hydrofluoroethers, are produced globally in high quantities as refrigerants but can breakdown in the atmosphere to form PFBA,” Garnett said.
Some previously used ozone-depleting substances were banned under the 1987 Montreal Protocol. However more research is needed to better understand the effects of replacement chemicals used, authors cautioned.
Despite the phasing out of PFOA, an increase in this chemical was seen from the mid-1980s onward in samples collected, with no evidence of a decline detected.
In addition, researchers suggested precursor chemicals emitted into the atmosphere by manufacturers could account for the large proportion of PFAS seen in this remote region, as “several chlorofluorocarbon-replacement chemicals have been identified as potential precursors to PFBA.”
After being wafted through the atmosphere and degraded by sunlight, snow then deposits these chemicals into the Antarctic surface.
“These findings are a sobering reminder that our industrial activities have global consequences,” said co-author Anna Jones of the British Antarctic Survey.
“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.”
Published on Jul 29,2022