Research Director, Department of Chemica l and Biological Work Environment, National Institute of Occupational Health in O slo, Norway, as well as professor in environmental chemistry, Department of Plant and Environme ntal Sciences, at the Norwegian University of Life Sciences outside Oslo. Thomassen is the author or co-author of 190 scientific publi cations, the majority focusing on atomic spectrometry and other spectrometric methods for t he determination of essential and toxic elements with special emphasis on electrothermal a tomic absorption spectrometry.