| Summary: | 碩士 === 長榮大學 === 職業安全與衛生學系碩士班 === 99 === In this study welding workers’ exposure to four metals including manganese (Mn), nickel (Ni), chromium (Cr) and iron (Fe) from metal fume were measured. Two groups (exposed and non-exposed groups) of study subjects were recruited for this study. The exposed group included welding workers from the welding processes of a high-tech plants manufacturing factory and the non-exposed group consisted of administrators in the same factory. Personal air exposure samples and environmental air samples and were collected on 3~5 workdays of a week in each month in a half year. Personal biological monitoring samples (urine) were also collected at different time spots during the air-sampling period. The air samples were taken by using an IOM sampler with a MCE filter. All the samples were digested in a microwave oven system. The content of the metals in the samples were quantified by using an atomic absorption spectrometry equipped with a graphite furnace. During the exposure sampling period, work activities of the workers were observed and recorded and a self-administered questionnaire was used to collect the demographic information and work history of the workers. In the study, 26 personal air exposure samples and 30 area air samples were obtained. The numbers of urine samples collected from the exposed and non-exposed groups were 109 and 30, respectively. The concentrations of Mn, Ni, Cr and Fe in the air of the work environment of two welding areas (A and B) were 0.00323, 0.00102, 0.00111 and 0.00567 mg/m3 for Area A and 0.00971、0.00092、0.00099 and 0.03144 mg/m3 for Area B. The concentrations of Mn, Ni and Fe in the pre-shift urine samples collected from the exposed group in each month of the half year (long-term measurement) were higher than those in the post-shift urine samples, but the concentration of Cr in the post-shift urine samples was higher then that in the pre-shift urine samples. The concentrations of these four metals in the pre-shift urine samples collected from the exposed group in each work day of a month (short-term measurement) were higher than those in the post-shift urine samples. Based on the results of paired-t tests, the metal concentrations of both long-term and short-term urine measurements showed statistically significant differences between the pre-shift and the post-shift urine samples. The Mn, Ni and Cr concentrations of the pre-shift urine samples of the non-exposed group were higher than those in the long-term measurements of the exposed group. But, the Mn and Fe concentrations of the post-shift urine samples of the non-exposed group were only a little bit higher than those in the long-term measurements of the exposed group. In comparison with the metal concentrations of the short-term measurements of the exposed-group, the metal concentrations of the pre- or post-shift urine samples of the non-exposed groups were lower than those of the exposed-group. The metal concentrations of the pre-shift urine samples with creatinine adjustment were lower than those of the post-shift urine samples. This indicated that the welding workers were exposed to welding metal fume. However, the metal fume exposure level of the workers was lower than the permissible occupational limits.
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