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 reported^2,3, 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.