My doctoral dissertation concerned the determination of a number of trace elements in dated snow and ice layers from the Arctic. Subsequently, I spent since November 1994 one year in Perth for gaining experience in isotopic analysis in the same area of glaciological research. During the proposed stay I want to expand first the results available for organolead compounds in Greenland by analysing various snow and ice samples (from now to 200.000 years ago) from central Greenland, East Antarctica and alpine mid-latitude glaciers. In addition, I intend to apply an adapted methodology for the determination of methylated organoselenium and organogermanium compounds. In a second stage I want to take part in the development of new procedures for the determination of organometal compounds with increased analytical characteristics detection limits based on the automation of the preconcentration steps and the development of novel methods of detection of the chromatography effluent with mass spectrometry detectors. In the course of my stay I will participate in the exploitation of methodologies available for microscopical characterization based on electron microprobe analysis and ion miroprobe analysis with dynamic and static secondary SIMS on particles collected from dated snow/ice layers.