Variations in lead isotopes in Antarctic snow from northern Victoria Land during 2012-2015

To evaluate recent changes in anthropogenic Pb pollution and its sources and origins in Antarctica, Pb and Ba concentrations and Pb isotopic compositions were determined in a continuous series of 40 snow samples from a 2-m deep snow pit, covering 4 full years from 2011/12 summer to 2015/16 summer, at the Hercules Névé plateau in Victoria Land, Antarctica. The results show that more than 90% of the atmospheric Pb deposited in Victoria Land was of noncrustal origin. This result implies the persistence of a significant human impact on the atmospheric cycle of Pb in the most remote places on Earth, despite a substantial reduction in anthropogenic Pb emissions in the Southern Hemisphere during recent years. The Pb isotopic fingerprints indicate that South America, particularly Brazil and Chile, has become a major source of anthropogenic Pb reaching Victoria Land. Our data highlight the need for both national and international measures to further reduce Pb emissions.