Aim of the proposed research is to study the applicability of tracer techniques, developed in the geosciences, to the field of environmental toxicology. Lead isotope systematics, lanthanide systematics and selected trace elements will be studied in soils, dust, food, human blood and toe-nails in selected and well constrained cases of environmental exposure of human populations to heavy metals. Transferroutes of pollutants in the environment and levels of endogenic exposure to these pollutants are still poorly understood. Tools enabling the identification of sources, transferroutes and also quantification of the levels of the exposure would be of great value both scientific and legally, as identification of sources of pollution would enable authorities to take adequate action. Training of the applicant will be twofold: by training in the analysis lead isotopes, lanthanides and selected trace elements at low concentration levels in human blood, dust, food and soils, and by attending a post graduate course in toxicology at the University of Vienna. As part of the toxicological training biological effect parameters will be determined in blood from selected subjects.