火力發電廠周界空氣微粒與兒童尿中重金屬濃度之評估研究

Levels of heavy metals in particulate matters and in urine of children in the vicinity of a coal-fired power plant

林右翎(You-Ling Lin)

指導教授 ： 詹長權

國立臺灣大學/公共衛生學院/職業醫學與工業衛生研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.02425

摘要

背景：
許多研究指出火力發電廠燃煤過程產生之煙塵附著之重金屬產生人體健康之危害。本研究藉比較台中火力發電廠周邊之高暴露區與低暴露區兩大地區孩童尿液中重金屬濃度之差異與分布趨勢，以評估台中火力發電廠對附近孩童尿液中重金屬濃度影響。

方法：
選取距離台中火力發電廠 7 公里內且位於下風處彰化縣伸港鄉 A 村及 B 村為高暴露區，以線西測站監測之 PM10、PM2.5、SO2和NOX 濃度做為該區的空氣污染暴露資料，另外選取出距離發電廠 7－10 公里且位於上風處的台中縣龍井鄉C村為低暴露區，並以沙鹿測站監測資料代表該區的暴露。以隨機抽樣方式選取兩區的 1－12 歲之孩童 224 名為對象，收集其尿液樣本，並以感應耦合電漿質譜儀（ICP－MS）方法偵測尿液中重金屬濃度（錳、鎳、銅、砷、硒、鎘、鉛），另外再輔以問卷調查，收集與重金屬暴露相關的孩童個人資料及其他環境暴露因子。同時在 2009 年四月及八月在高、低暴露區分別進行兩次空氣微粒實地採樣，除取得 PM10 及 PM2.5 的質量濃度之外，並以 ICP－MS 方法進行微粒中重金屬成分分析（錳、鎳、銅、砷、硒、鎘、鉛）。資料彙整之後運用 t－test 比較高、低暴露區孩童尿液重金屬濃度，Mann-Whitney U Test 比較空氣中 PM濃度之差異，及複迴歸模式分析控制干擾因子，使用 SAS 9.1 版進行資料分析，估計空氣中 PM 濃度對孩童尿液重金屬濃度之影響。

結果：
本研究共收集台中火力發電廠附近之高暴露區孩童尿液樣本 122 份與低暴露區孩童尿液樣本 71 份，回收率為 72.3 %。研究發現，孩童尿液樣本收集前一周空氣中 PM10 及 PM2.5 的暴露情形在高暴露區顯著高於低暴露區，但是從兩個地區 4 月及 8 月空氣微粒實地採樣結果顯示之 PM10 及 PM2.5 濃度在高、低暴露區未達統計上顯著差異。而微粒中銅、砷、鎘和鉛濃度雖然在高暴露區稍高於低暴露區，但未達顯著差異。以 t-test 比較則發現高暴露區孩童尿中錳和砷濃度顯著高於低暴露區孩童，高暴露區孩童尿中銅和鎳濃度顯著低於低暴露區孩童。以複迴歸模式分析，在控制性別、年齡、BMI、家庭收入、二手煙暴露、飲用地下水暴露、食用海鮮與鄰近工廠暴露等因子之後，發現高暴露區孩童尿中砷濃度顯著高於低暴露區孩童，高暴露區孩童尿中銅和鎳濃度則顯著低於低暴露區孩童。在複迴歸模式加入收尿日前一周空氣中 PM10 及 PM2.5 暴露之後發現，PM10 及 PM2.5暴露與孩童尿中錳、砷和硒濃度達顯著正相關。模式結果同時也發現，女生尿中錳濃度顯著高於男生，學齡前孩童尿中錳和硒顯著高於學齡孩童，低收入家庭之孩童尿中錳濃度顯著高於高收入家庭之孩童，然而高收入家庭之孩童尿中砷濃度顯著高於低收入家庭之孩童，飲用地下水的孩童尿中硒濃度顯著高於未飲用地下水的孩童。

結論：
居住在台中火力發電廠下風處之孩童尿中砷濃度及其PM10 和 PM2.5 暴露量皆顯著高於居住在發電廠上風處之孩童。

關鍵字

燃煤火力發電廠 ； 空氣污染 ； 金屬 ； 尿液 ； 孩童

並列摘要

Background：Many studies have shown that coal-fired power plants emit heavy metal particulate matters which could induce health hazards. The purpose of this study was to evaluate the impact of emissions from the Taichung coal-fired power plant on the urinay heavy metal levels of children living in communities at different distances from the plant.

Methods：Communities located downwind and within 7 kilometers from the plant, village A and B, in Shengang Township of Changhua County, were defined as the high exposure area (HE), village C, in Longjing Township of Taichung County, located upwind and 7 to 10 kilometers from the plant, was chosen as the low exposure area (LE). The concentrations of PM10, PM2.5, SO2 and NOX from the Siansi and the Shalu air quality monitoring stations were used to estimate air pollution exposures for children in HE and LE, respectively. Ambient air sampling for PM10 and PM2.5 was conducted in HE and LE in April and August, 2009, and metals in PM10 and PM2.5 were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Children aged 1 to 12 years were randomly sampled from HE and LE and were invited to participate in this study after signing an informed consent. One spot urine sample were collected from each child, and the urinary levels of seven metals (Mn, Ni, Cu, As, Se, Cd and Pb) were determined by ICP-MS. Questionnaires were used to collect the information about each child’s heavy metal exposures from different sources and other important factors. The Student’s t-test was used to compare the urinary levels of each metal and the Mann-Whitney U Test was used to compare PM10 and PM2.5 samples at specific time windows between children in HE and in LE. The multiple regression models were applied to assess the influences of PM10 and PM2.5 exposures on urinary metal levels, with adjustment for confounding factors.

Results：In total, 224 children participated in this study, with a response rate of 72.3 %. After excluding children with extreme urinary concentrations of creatinine, the data from 193 children were included in this study. The concentrations of PM10 and PM2.5 during the week before collection of urine samples were significantly higher for children in HE than for those in LE. The concentrations of Cu, As, Cd, and Pb in the PM10 and PM2.5 samples collected from HE were higher than those from LE but without statistical significance. Children in HE had significantly higher urinary Mn and As levels, but significantly lower urinary Ni and Cu levels, than did those in LE. After adjusting for gender, age, BMI, family income level, exposures to ETS, drinking water source, consumpsion of seafood and other potential confounding factories, children in HE had a significantly higher urinary As level than did those in LE. However, children in HE had significantly lower urinary Ni and Cu levels than those in those in LE. When exposure to PM10 and PM2.5 during the week before urine sample collection was included in the multiple regression models, there was positive significant associations between PM10 and PM2.5 and urinary levels of Mn, As and Se, respectively. Furthermore, the results of the regression analysis indicates a significantly higher geometric mean urinary Mn level in girls than in boys and a significantly higher urinary Mn and Se levels in pre-school children than in school children. There was a significantly lower urinary Mn level, but significantly higher urinary As level, in children with high family income level than in those with low family income. Children drinking underground water had a significantly higher urinary Se level than did those drinking tap water.

Conclusions：Children living in the downwind area of the coal-fired power plant had significantly higher urinary level of arsenic and higher exposures to PM10 and PM2.5 than did children in the upwind area.

並列關鍵字

coal-fired power plant ； air pollution ； metals ； urine ； children

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