Radon-222 daughter concentrations in uranium mine atmospheres.

Abstract

THE principal radiation exposure of a uranium miner is to the lungs and results from inhaling short-lived 222Rn daughter products (Fig. 1) in the atmosphere1. The short-lived daughters (RaA, RaB, RaC and RaC′) decay in the lung to 22-year 210Pb, of which a fraction is absorbed into the blood stream and stored in the skeleton. Correlation coefficients of 0.84 and 0.77 between exposure to the short-lived daughter products and the 210Pb skeletal burden have been reported2,3, but these studies indicate that the concentration of 210Pb in bone may be as much as four times that expected from the inhalation of the short-lived radon daughter atoms alone3. Less than 10 per cent of additional skeletal 210Pb can be expected from inhaled 222Rn stored in body fat. In order that the concentration of 210Pb in bone should be a valid index of exposure to the 222Rn daughter products, it must be shown that 210Pb atoms supplied by other sources are proportional to the 222Rn daughter concentration.