A record of the past and recent changes in the large scale atmospheric cycles of Pb and other heavy metals can be found in the successive dated ice and snow layers stored in the Antarctic and Greenland ice caps. Deciphering these frozen archives has however been possible only when using sophisticated ultrasensitive and ultraclean analytical techniques. The available data have allowed to demonstrate that the atmospheric cycles of heavy metals have been highly dependent upon climate during pre-pollution times. During the last few centuries, they have been significantly altered by man. This is especially the case for Pb, whose concentrations were found to have strongly increased in Greenland ice and snow from several millennia ago to the mid 1960's, then to have decreased from the late 1960's to present.
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