A 20-year follow-up study on the effects of long-term exposure to thorium dust.
OBJECTIVE
To investigate the possible effects of long-term exposure to dust containing thorium and thoron progeny on dust-exposed miners.


METHODS
A negative, high voltage, exhaled thoron progeny measurement system was used to estimate the miners' thorium lung burden.


RESULTS
The highest thorium lung burden of 638 miners was 11.11 Bq. The incidence of stage 0(+) pneumoconiosis was higher among dust-exposed miners. Lung cancer mortality of the dust-exposed miners was significantly higher than that of controls (P < 0.005).


CONCLUSIONS
There is a difference in cancer rates between those who have long-term exposure to dust containing thorium (in which carcinogenic ThO(2) and SiO(2) exist) and thoron progeny and those who have not.
Chen
Xing'an
X
Laboratory of Industrial Hygiene, Ministry of Health, Beijing 100088, China. chenxing_an@hotmail.com
Cheng
Yonge
Y
Xiao
Huijuan
H
Feng
Guodong
G
Deng
Yunhui
Y
Feng
Zhiliang
Z
Chen
Lian
L
Han
Xuanmao
X
Yang
Yingjie
Y
Dong
Zhihuan
Z
Zhen
Rong
R
D000396:Air Pollutants, Radioactive / Q000009:adverse effects; D001822:Body Burden; D002681:China / Q000453:epidemiology; D004391:Dust; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology*; D008906:Mining; D009784:Occupational Diseases / Q000453:epidemiology*; D016273:Occupational Exposure / Q000009:adverse effects; D013910:Thorium / Q000009:adverse effects*
D000396:Air Pollutants, Radioactive; D004391:Dust; D013910:Thorium