High Specific Activity radioactive tracers: a powerful tool for studying Low Level and Long Term Exposure to different chemical forms of both essential and toxic elements

A review. Both essential and toxic elements are present in the biosphere in different inorg. and organo-metallic forms. Some trace elements like Cr, Cu, Mn, Rb, Se, Tl, V, Zn are essential to human life and are present in human tissues, body fluids, cells and sub-cellular components, bonded to enzymes, proteins, etc. Many trace elements are introduced daily in the body in amounts. ranging from ng to μg per kg. A powerful tool to set up analytical procedures, to evaluate the chemical separation yield and to follow the fate of different chemical forms of ultra-trace elements on living organisms is the use of high specific activity' radioactive tracers (RT). Amongst the more effective RTs for radio-analytical chemistry, there are short-lived medium γ-energy emitters. A review of the last 25 yr in the field of both cyclotron and nuclear reactors producing high specific activity radionuclides in radio-analytical chemistry is presented. As, Au, Cu, Ga, Mn, Np, Pd, Pt, Rb, Rh, Sb, Te, Ti, Tl, V, etc., γ- and β-emitting RTs have had interesting applications in the ultra-trace metallo-toxicological field. High-resoln. γ-spectrometry by HPGe detection and β spectrometry by liq. scintillation counting, have been used, hyphenated with elemental analytical, radio-analytical and analytical techniques. The high specific activity of the no carrier added RTs is the key factor of this powerful radio analytical technique.