In a first, fly ash particles found in Antarctic ice, thousands of kilometres from potential source
Spheroidal carbonaceous particles (SCP), a component of fly ash, have been identified for the first time in an Antarctic ice core, according to a new study. Not just that, the particles recovered dated back to 1936, according to scientists from British Antarctic Survey and the University College London.
SCPs have no other anthropogenic or natural sources other than fossil fuel combustion. Thus, they are an unambiguous environmental indicator of industrialisation.
The most probable source of the identified SCPs was the Australian coal-fired power plants (some 8,000 kilometres away), with potential additional input from South America in central Chile, 4500 km away, the scientists said in the report published in the journal.
The study provided the first evidence that SCPs have not only been transported to continental Antarctica, but that those enduring physical markers of fossil fuel combustion have been trapped in ice layers since the early decades of the 20th century.
The researchers wrote:
Atmospheric circulation and transport processes have probably influenced the deposition of SCPs in Antarctica throughout the twentieth century, especially related to the strength and position of the Southern Hemisphere westerly winds.
The westerly winds are predicted to increase in strength during the 21st century and this might lead to an increased deposition of fly ash particles and other anthropogenically-derived atmospheric pollutants in Antarctica in the future, they noted.
The researchers presented SCP data from annually resolved samples from 1900-2011, taken from an ice core collected from the Palmer Land region of the Antarctic Peninsula.
The oldest potential evidence of SCPs at Palmer was found in the sample corresponding to 1930-1937. However, the first definitive year, identified from the discrete sampling method at an annual resolution, was observed in 1936, the report elaborated.
The SCPs identified within the ice core were analysed using scanning electron microscopy and energy-dispersive x-ray to determine their surface chemistry and fuel source.
In the past, ice cores have been drilled from ice sheets worldwide and notably in Greenland and Antarctica. Scientists can unravel the compostition and timeline of accumulated samples as well measure the temperature and chemistry of air from another time by studying ice cores.
Russia’s nuclear power station at Chernobyl exploded in April 1986. The accident and the fire that followed released massive amounts of radioactive material into the environment. Less than two years later, scientists detected Chernobyl radioactivity in the snow in the South Pole.
Atmospheric transport is the main means by which contaminants reach Antarctica. The closest sources are furthest south in South America.
The Troll Observatory has been able to trace aerosols measured locally back to forest fires in Brazil four weeks earlier.
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