Changes in the natural lead, cadmium, zinc, and copper concentrations in the Vostok Antarctic ice over the last two glacial-interglacial cycles (240,000 years)

Abstract

We present new ice core records showing the temporal variation in the natural Pb, Cd, Zn, and Cu concentrations in the Vostok Antarctic ice over the past 240,000 years. Our data show that concentrations of these heavy metals have varied remarkably over the last two glacial-interglacial cycles. The concentrations ranged from 0.9 to 21.3, 0.04 to 0.62, 3.12 to 126, and 2.27 to 37.4 pg/g for Ph, Cd, Zn, and Cu, respectively. These profiles provide a better understanding of climate-related variation in the occurrence of these heavy metals in ancient Antarctic ice. The concentrations were much higher during cold glacial periods than during interglacials, and peaked at the coldest glacial stages. The contribution of rock and soil dust is estimated to be close to the measured concentrations of Pb, Zn, and Cu, but not Cd, in the ice during cold glacial periods.