An observation on the clearance of thorium dioxide from the lung of a miner

• Published in: Journal of radiological protection 1995-12, Vol.15 (4), p.343-346
• Main Authors: Chen, Xing-An, Xiao, Hui-Juan, Cheng, Yong-e, Yang, Ying-Je
• Format: Article
• Language: English
• ISSN: 0952-4746; 1361-6498
• DOI: 10.1088/0952-4746/15/4/006

In this account we report the results of exhaled thoron activity measurements and thorium lung burden estimates performed on a subject during the period 1983 to 1990. Our findings are very interesting in that they point clearly to a very very slow turnover of part of the intake by the lung. In view of the rarity of such data for human subjects, except for those injected with Thorotrast, the investigations and results are presented in some detail. The subject was a miner in the crushing workshop of Baiyan Obo Iron and Rare Earth Coexistence Mine during the period 1958-92. The dust concentration in the crushing workshop is in the range 9.30-875.0 mg m super(-3), mean 188.71 mg m super(-3). The composition of the dust contains not only iron, rare-earth elements, silica dioxide but also thorium. Thorium is at 0.04%. In 1983, we had found that the thorium lung burden of this subject was the highest in this mine. The follow-up study of his thorium lung burden before and after his leaving the dust post has been carried out since then.