Natural radioisotopes 210Pa and 210Pb in human hair as an indicator of exposure

The potential of naturally-occurring polonium (Po-210) and radioactive lead (Pb-210) in human hair as bio indicators for internal contamination by uranium series nuclides was investigated through analysis of hair samples in 87 individuals. The hair samples were collected in three groups of the Portuguese population, namely workers of the uranium mining industry, inhabitants of a county in a high radiation background region of the centre-North of Portugal, and inhabitants of the Lisbon area, a region of low environmental radioactivity. Radio nuclides were determined by alpha spectrometry. Results allowed for a comparison of radionuclide concentrations amongst these groups, being the uranium miners the group with higher concentrations and the Lisbon group the one with lowest concentrations of radio nuclides in the hair. Furthermore, Po-210 and Pb-210 concentrations were investigated as a function of individuals' age. Results show a significant increase of Po-210 concentrations with the age, while Pb-210 concentrations remain nearly constant with the age. The excretion of Po-210 incorporated in the hair reflects the size of the internal Po-210 deposit and the increase of the deposit of Po-210 parent radio nuclides with age. It is suggested that analysis of hair may enable the detection of elevated concentrations of Po-210 parent nuclides accumulated in the body.