Present status of polonium tolerance estimations

This report contains a summary of biological information on distribution, excretion, and toxicity of polonium; a comparison of results obtained when maximum permissible exposure rates for man are calculated from available data by different methods; and a critical evaluation of the present status of Po tolerance estimates. A maximum permissible body content of the order of 0.2 {mu}c/70 Kg man is obtained by two methods. Applying an urinary excretion rate of 0.1% of body content/day, effective half-life of 34 days, and certain corrections for the non-exponential nature of Pb excretion, maximum permissible air and water concentrations and urinary excretion rates have been computed. Extrapolation from present data to calculations of tolerance levels in man is still difficult, and there appears to be no substitute for actual long term experiments. On the other hand, permissible exposure levels quoted herein appear to be, to a large extent, consistent with conservative practice