High altitude cold snow and ice cores from midlatitude mountain ranges have been used very little to obtain historical records of environmental contamination by heavy metals. Co, Cr, Mo, and Sb have been measured by DF-ICP-MSMCN (double focusinginductively coupled plasma mass spectrometry with microconcentric nebulizer) in various sections of a 140 m snow/ice core drilled at a high altitude location near the summit of Mont Blanc in the French-Italian Alps. The bottom of the core is older than200 years. It gives the first snow and ice time series for these metals of high environmental interest for the post Industrial Revolution period. Measured concentrations range from 26 to 433 pg/g for Co, from 8 to 469 pg/g for Cr, from 0.2 to 50 pg/g forMo, and from 0.2 to 109 pg/g for Sb. For all four metals, concentrations in recent snow are found to be, on the average, significantly higher than concentrations in ice dated from before the middle of the 19th century. There are however differences in the timing and the amplitude of the observed increases from one metal to another. Mo shows the greatest increase (×16), followed by Sb (×5), and Co and Cr(×2-3). Contribution from natural sources is, on the average, limited except for Mo in ice dated frombefore the middle of the 19th century. For recent snow, contribution from oil and coal combustion is the dominating source for Co, Mo, and Sb. For Cr, on the other hand, the most important contribution is from iron, steel, and ferroalloy industries.
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