Trends of contaminants in Antarctica
With few local sources, contaminant levels in Antarctica to some extent reflect global pollution trends.
Analyses of snow and ice cores from Coats Land, Victoria Land and Law Dome have shown that Antarctica was contaminated as early as 1880 by lead that could be traced back to the metallurgical industry in South America, South Africa and Australia. Another source may have been steamships. Lead levels then sank in the 1920s, and it has been speculated that this was related to the opening of the Panama Canal in 1914, which resulted in less shipping. Lead contamination then increased significantly during the Second World War (1939-1945) due to more activity in the metallurgical industry and a high lead content in petrol. The analyses of the snow samples have shown a reduction from the 1980s to the present day, probably because of the introduction of lead-free fuel.
A study of a number of organic pollutants (HCB, heptachlor, HCH, heptachlor epoxide) in air, seawater, sea ice and snow from the Antarctic Peninsula has shown that the levels of several of the substances have declined. Heptachlor epoxide levels, however, have not dropped during the past decade, suggesting that heptachlor is still being used in the Southern Hemisphere. It was used a great deal to combat termites in the 1960s and ‘70s. The USA banned its use in 1988.