| Summary: | 碩士 === 國立臺灣大學 === 公共衛生碩士學位學程 === 104 === Gallium arsenide is widely used in the microelectronics industry; workers involved in the cutting, grinding, sandblasting, and cleaning of gallium arsenide wafers may be exposed to gallium arsenide particles, leading to health hazards.
This study targeted the health risk assessment of semiconductor industry workers’ exposure to gallium arsenide particles from the manufacture of AlGaInP Light Emitting Diode (LEDs) chips. The health risk assessment process was conducted in four main parts: hazard identification, dose-response assessment, exposure assessment, and risk characterization. Chronic toxicity study found female rats developing alveolar and bronchial cancer when exposed to 0.1 mg/m3 and 1 mg/m3. The concentrations from chronic inhalation studies by NTP (2000) were converted to dosages and entered in the Benchmark Dose software for asssessment; the resulting estimation was 0.02 mg/kg-bw/day with a cancer slope factor (CSF) of 5(mg/kg/day)-1. To account for animal and human inhalation differences, a total uncertainty factor of 100 from inter-species extrapolation factor of 10 and human sensitivity factor of 10 was assigned. The resulting reference concentration and cancer slope factor (CSF) of gallium arsenide in human was 0.05(mg/kg/day)-1.
After a walkthrough survey, lithography stations and AlGaInP trimming sations were selected to collect short-term environmental samples to assess workers’ chronic exposure. The calculated cancer risk of exposure to gallium arsenide from working at the manufacturing process was 6.15*10-7; the cancer risk of working at lithography station was 3.91*10-9; AlGaInP trimming station was 1.23*10-6. The cancer risks of exposure to arsenic and gallium were 6.97*10-8 and 1.03*10-7, respectively. The risks were all within the acceptable threshold for occupational risk of10-4.
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