Formation, Occurrence and Health Risks of DBPs in Drinking Water (I)

本年度計劃針對含鹵乙酸之分析及其在水中之流佈 加以探討。結果顯示含鹵乙酸前處理之測試最佳條件 如下：使用4 ml MTBE 做為萃取溶劑，以2ml 10 ％硫 酸甲醇溶液，75 ℃，30 分鐘之水浴進行衍生後，衍生 之乙酸甲酯以4ml 10 ％硫酸鈉溶液萃取，最後樣本添 加1ml 的正己烷後，再經吹氮濃縮，並注入氣相層析 質譜儀（GC-EIMS）以SIM mode 設定分析。本研究之 9 種含鹵乙酸之方法偵測極限介於0.25-1.48 μg/L 之間。台灣各地區9 種含鹵乙酸採樣分析結果顯示，HAA 總濃度大約分佈在ND-117.44 μg/L 之間，大多都符合 美國現階段HAA5 總濃度60 μg/L 之標準。然而不同地 區由於水源特性的差異，使得各地區含鹵乙酸物種及 濃度的分佈上也有所不同。HAA 與THM 有類似之季節 性變化趨勢，在夏季之濃度高於冬季，且外島地區濃度高於台灣本島。This year’s project focus on the analysis of HAAs in drinking water. A procedure was proposed for best HAA analysis. In sample preparation, 4ml MTBE is use for the extraction of 60 mL water sample, and the methylation is conducted with 2ml of 10 ％sulfuric acid in methanol. The derivatization temperature is set at 75 ℃ for 30 minutes. After methylation, the acidic methanol mixture extract with 4ml 10 ％ sodium sulfate solution. At last step, 1ml hexane was added to the mixture. After concentration to 0.3 mL, the mixture was then injected to GC-EIMS with selected ion monitoring (SIM) mode. The MDLs for all nine HAAs are between 0.25µg/L and 1.48µg/L. It was observed that total HAAs concentrations (HAA9) are between ND and 117.44 µg/L in Taiwan. Most of the HAA5 concentrations are below the MCL specified by US EPA (60µg/L). However, due to various raw water qualities, huge variation was observed for HAA concentrations in different water treatment plants. Both HAAs and THMs have similar trends: their concentrations vary seasonally and are typically highest in the summer. Water treatment plants in King-Men have highest HAA concentrations than in Taiwan