Heavy metals in ancient tropical ice: initial results

Although a wealth of fascinating data have been obtained through the invest igation of heavy metals in Greenland, Antarctic and Alpine snow and ice cor es, heavy metals have until now never been measured in tropical snow and ic e cores despite the great interest of such low latitude cores. We present h ere preliminary data on the occurrence of Al, Na, Ti, V, Cr, Mn, Co, Cu, Zn , Mo, Pd, Ag, Cd, Sb, Ba, Pt. Au, Pb, Bi and U in a dated ice core drilled at an altitude of 6542 m on the top of Sajama in Bolivia. These data were o btained by analysing four core sections dated 22,000 BP (Last Glacial Maxim um, LGM), 8000 BP (early Holocene, EH), AD1650 and AD1897, using ultrasensi tive ICP-SF-MS. Concentrations observed in LGM ice are similar to those mea sured in EH ice. Al. Na, Ti, V, Cr, Mn, Co, Ba and U are found to derive ma inly from rock and soil dust. For the other metals, additional contribution s from other sources are needed to explain the observed concentrations. (C) 2001 Elsevier Science Ltd. All rights reserved.