Transportability of industrial plutonium aerosols as an objective characteristic of lung clearance for Mayak PA workers

The procedures recommended in ICRP Publications 30 and 66 for calculating radiation doses from inhaled radionuclides include classification of material on the basis of different parameters, among which transportability plays a major role. This paper contains a description of a dialysis method by which potentially inhaled workplace plutonium-containing aerosols are classified on the basis of in vitro measured transportability in Ringer's solution for worker dosimetry assessments. Transportability is measured as the fraction of plutonium alpha-activity, deposited on a collecting filter, that passes through a semi-permeable membrane in Ringer's physiological solution during two days of dialysis, First order kinetic equations are used to explain the dialysis results. Study of the dialysis kinetics have shown the correlation between the dialysis rate and chemical characteristics of plutonium compounds. According to the research of more than 700 postmortem cases of Mayak workers, it was revealed that the relative plutonium content in the respiratory tract determined at autopsy is inversely correlated with transportability of industrial aerosols, measured by the dialysis method. The dissolution characteristics of alpha-active aerosols are important in interpretation of their transfer processes in the lungs after inhalation.