Within the framework of the Protection of the Environment programme of the JRC-Ispra of the European Community, research on trace metal exposure and health effects is concerned primarily with the toxicological assessment of present levels of trace metals in the tissues of exposed and unexposed populations. Main activities are: (1) microdetermination of trace elements in human tissues in order to generate an accurate and reliable data base on the levels and biochemical forms of trace metals in differently exposed humans; (2) metabolism and biochemical mechanisms involving trace metals to assess the toxicological significance of the current levels of the elements in the human body. Few selected applications related to the different steps of the biochemical toxicology research are shown. They concern the long-term behaviour of trace metals at the target tissues of laboratory animals, the biological monitoring of vanadium in workers during maintenance operations at an oil fired power plant for energy production, and the biochemical mechanism of methylation of arsenic in vivo.
Authors:E. Sabbioni, R. Pietra, J. Edel and L. Goetz
In order to prepare scientifically accurate health protection criteria documents for trace metals integrated multidisciplinary research is necessary. In particular, the rational for structuring the documents should be based primarily on the two major questions of exposure and response. Unfortunately, in a majority of cases there is a paucity of relevant data to the establishment of dose-effect relationships. This work intends to show the role that neutron activation analysis and radiotracers with very high specific radioactivity have in solving problems relevant for establishing dose-effect relationships for trace metals. Typical applications in the different research areas involved in the preparation of the protection criteria, from source and exposure to levels and forms of trace metals in humans, are presented.
Authors:L. Goetz, E. Sabbioni, E. Marafante, J. Edel-Rade, C. Birattari and M. Bonardi
Carrier-free201+202Tl have been produced in the cyclotron by (p, xn) reactions on mercury targets and used as a trcer for thallium in metallobiochemistry
of heavy metal pollution. The separation of201+202Tl radioisotopes from Hg involved a solvent extraction method leading to labelled univalent Tl(I) ions. This radioactive solution
was used to prepare different201+202Tl labelled compounds such as inorganic Tl(III) ions and organic dimethylthallium. Quality controls have been applied directly
on the different radioactive solutions immediately before their administrations to rats in order to ensure that thallium had
the chemical form expected. A summary of the main results concerning different aspects of the metabolic investigations on
rats such as absorption, retention, excretion, transplacental transport and influence of the different chemical forms of thallium
on its metabolism is also reported.