Radon and thoron emanation from various marble materials: impact on the workers

Uranium (238U) and thorium (232Th) concentrations were measured inside different pulverized marble material samples by using a method based on determining detection efficiencies of the CR-39 and LR-115 II solid state nuclear track detectors for the emitted alpha particles. Radon (222Rn) and thoron (220Rn) alpha-activities per unit volume were evaluated inside and outside the marble samples studied. Radon emanation coefficient was determined for the considered marble samples. Alpha- and beta-activities per unit volume of air due to radon, thoron and their progenies were measured in the atmosphere of a marble factory. Equilibrium factors between radon and its progeny and thoron and its decay products were evaluated in the air of the studied marble factory. The committed equivalent doses due to short-lived radon decay products were determined in different regions of the respiratory tract of workers in the considered marble factory.