| Summary: | 碩士 === 中國醫藥大學 === 環境醫學研究所碩士班 === 98 === In 1997, crystalline free silica was classified by the International Agency for Research on Cancer (IARC) as a Group 1 carcinogen. Long-term exposure to free silica may cause serious injury to the respiratory system, such as the development of silicosis, bronchitis cancer, etc.. Foundry is the base of economic development in Taiwan, but its working place may generate particulates of different sizes in the fugitive dust, including the crystalline free silica. We conducted this study to comprehend the distributions of particulate concentrations and sizes at work. We sampld the respirable crystalline free silica using Micro-Orifice Uniform Deposition Impactor, and analyzed the crystalline free silica in different filters using X-ray Diffractometer. The results revealed that the dusts at the foundry in the air are coarse types (particle size >4 μm), consisting of 46.92-78.90% of the total dusts. In addition, the crystalline free silica in the air was also mainly coarse particle with the size >4 μm), consisting of 69.64-97.48% of the total crystalline free silica. Moreover, the silicosis risk for the foundry employees was estimated for 1.3-6.8×10-3, significantly higher than the risk level (10-3) defined by US Supreme Court. We also found a positive correlation between levels of urinary 8-OHdG and exposure level of crystalline free silica for workers at the foundry. In conclusion, the workers in foundry industry are recommended to wear an appropriate personal protective equipment or to follow proper ways of management to reduce the crystalline free silica exposure.
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