RESUMO
The problem of poisoning with thallium-containing substances continues to be of current concern. According to the Bureau of Forensic Medical Examination, Moscow, specimens of biological materials from more than 20 victims of such poisoning were delivered for analysis in 2006. The total number of thallium poisoning episodes during the period since 1996 exceeded 50. Materials for thallium determination in biological fluids (human blood and urine) using flame atomic absorption spectrometry were prepared by dry mineralization of accurately weighed samples; acidic solutions of the products of mineralization were used for analysis. Due to peculiar kinetic features of thallium ion absorption in the gastro-intestinal tract, blood could not be used as a biological marker of poisoning. The level of thallium in urine samples was found to vary from 1.00 to 4,600 mcg/l (with the estimation of confidence intervals in each case). Results of chemical analysis correlated with pathological symptoms derived from the patients' discharge summaries and literature reports on dose-effect relationships. Based on these findings, practically all the examined cases were characterized as severe acute poisoning.