| Summary: | 碩士 === 國立臺灣大學 === 職業醫學與工業衛生研究所 === 100 === Background：Previous studies have shown coal-fired power plants emitted arsenic (As) and mercury (Hg) into environment but studies on the extent of human exposures to these pollutants in their surrounding areas are limited. This study aimed to use the biological markers of urine arsenic and mercury to evaluate adult’s exposures to As and Hg living near a big coal-power plant in Taiwan and identify personal and environmental factors associated with the exposures.
Methods：Based on wind direction and distance to a coal-fired power plant, our study areas includes two downwind high exposure areas (HE1 and HE2) within 5 km radius of the power plant, and a upwind low exposure area (LE2) outside the 5 km radius of the power plant. A total of 273 adults, aged 20 to 65 years, were randomly sampled from the HE and LE areas. Personal information and potential metal-related exposure factors were collected by questionnaire. The first morning urine specimen was collected twice form each person in 2009 and 2011, and the levels of urinary As and Hg were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Ambient PM10 and PM2.5 were sampled by Harvard Impactor, and arsenic in PM10 was analyzed by ICP-MS. The bio-monitoring and ambient air sampling data in these different areas were compared by Student’s t test, ANOVA and ANCOVA. Multiple regressions were applied to determine difference in urine As and Hg among areas adjusting for personal factors.
Results：Among the 273 adults aged at 43.55±12.64 years that were in this study, there are 125 males and 148 females, and in 83 subjects in HE1, 115 subjects HE2 and 75 subjects in LE2. The geometric means of urinary As were 87.35 (2.58) μg/g creatinine in HE1, 65.48 (2.28) μg/g creatinine in HE2, and 57.28 (2.18) μg/g creatinine in LE2, respectively, for study subjects in 2011. The geometric means of urinary Hg were 1.78 (2.16) μg/g creatinine in HE1, 1.04 (2.05) μg/g creatinine in HE2, and 0.88 (2.04) μg/g creatinine in LE2, respectively. Urinary As and Hg levels in HE1 were significantly higher than those in LE2. Higher urinary As levels were associated with subject’s distance to power plant, age, length of residence, and lack of education. Higher Hg levels were associated with subject’s distance to the power plant, gemder (female), age, lower education, non-smoking status and consumption of local fish. After adjusted for those confounders by ANCOVA and multiple regression, levels of urinary As and Hg in HE1 were still significantly higher than those in HE2 and LE2. The concentrations of As in PM10 were 1.45±0.68 ng/m3 in HE1, 2.49±0.96 ng/m3 in HE2, 0.76±0.27 ng/m3 in LE2, respectively.
Conclusion：Adult residents living within 5 km radius of a coal-fired power plant had significantly higher urinary As and Hg concentrations than those living beyond 5 km radius.
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