Occupational Hygiene around the World

Abstract
To conduct a retrospective exposure assessment for a study of silica, silicosis, and lung cancer, current exposure measurements and techniques were compared with industrial hygiene data that had been systematically collected in Chinese industries over the past three decades. Historically, sampling was usually confined to total dust evaluation and bulk silica determinations. For comparison, from 1988 through 1989, several special surveys were conducted in Chinese iron and copper mines in the Huangshi region of Hubei Province. In addition to the total dust and silica measurements using the traditional Chinese sampling system, data were collected using standard National Institute for Occupational Safety and Health (NIOSH) sampling equipment for respirable dust, total dust, particle size distribution, selected trace elements, radon, and fibers. Overall, total dust measurement using NIOSH sampling and analytical procedures were correlated to the corresponding Chinese measurement, r2=0.77. No statistically significant difference was observed between historical data from recent sampling cycles and the current measurements. Some current silica determinations using the Chinese phosphoric acid digestion method, with gravimetric analysis of the residue, were biased by the presence of insoluble oxides in the residues. Exposure to carcinogenic trace metals was limited in the copper and iron mines; however, substantial radon progeny levels were observed, in one case exceeding 40 WL. No installed asbestos was found in any of these mines nor were any fibers detected in the analyzed bulk samples. The completeness of the historical record of exposures in this group of workers makes it particularly well suited for epidemiological study of dust-related diseases. Wu, Z.; Heart, F.J.; Peng, K.; McCawley, M.A.; Chen, A.; Palassis, J.; Dosemeci, M.; Chen, J.; McLaughlin, J.K.; Rexing, S.H.; Blot, W.J.: Current Occupational Exposures in Chinese Iron and Copper Mines. Appl. Occup. Environ. Hyg. 7(11):735–743; 1992.