室內泳池加氯消毒副產物暴露與風險評估-以某大學泳池為例

Abstract

本研究對國立臺灣師範大學游泳池進行20次採樣，紀錄水溫、氣溫、pH值、餘氯濃度和游泳人數，分析總三鹵甲烷、鹵乙酸、總有機碳及濁度，發現池水總三鹵甲烷濃度介於31.75 - 182.33 µg/L，氣相總三鹵甲烷濃度介於13.70 - 63.86 µg/m3，池水鹵乙酸濃度介於48.09 - 126.47 µg/L。 用美國環保署開發之游泳者暴露模式評估總三鹵甲烷與鹵乙酸各暴露途徑之終身每日暴露量，結合致癌斜率係數，算出游泳暴露總三鹵甲烷之終身致癌總風險為1.85 × 10-6 - 1.05 × 10-5；暴露鹵乙酸之終身致癌總風險為4.21 × 10-7 - 1.18 × 10-6。結果顯示游泳暴露加氯消毒副產物之致癌風險，主要源自呼吸吸入總三鹵甲烷，建議室內泳池提高換氣率，降低氣相總三鹵甲烷濃度。 游泳人數與池水總三鹵甲烷、氣相總三鹵甲烷與池水鹵乙酸濃度呈正相關，池水總三鹵甲烷濃度亦與濁度呈正相關，建議泳池管理者限制每天入池人數，多對游泳者宣導入池前先沖洗身體，減少帶入的有機物量，並強化過濾系統之功能，以降低濁度。We sampled National Taiwan Normal University swimming pool 20 times, water temperature, air temperature, pH, concentrations of chlorine and number of swimmers were recorded. Concentrations of total trihalomethanes, haloacetic acids, total organic carbon and turbidity were analyzed. The results revealed that concentrations of total trihalomethanes in pool water ranged from 31.75 to 182.33 μg/L. Ambient air total trihalomethanes concentrations ranged from 13.70 to 63.86 μg/m3. Concentrations of haloacetic acids in pool water ranged from 48.09 to 126.47 μg/L. Swimmer exposure model developed by United States Environmental Protection Agency was used to assess lifeltime average daily dose from total trihalomethanes and haloacetic acids. Lifetime cancer risk was calculated by lifetime average daily dose times cancer slope factors. The results showed that lifetime cancer risk exposured to total trihalomethanes ranged from 1.85 × 10-6 to 1.05 × 10-5; while lifetime cancer risk exposured to haloacetic acids ranged from 4.21 × 10-7 to 1.18 × 10-6. According to the results, lifetime cancer risk exposured to chlorinated by-products, major contributed from inhaling of total trihalomethanes. Increasing ventilation rate of indoor pools may help decreasing the risk. The number of swimmers was positively correlated with concentrations of total trihalomethanes in pool water, total trihalomethanes in ambient air and haloacetic acids in pool water. Concentrations of total trihalomethanes in pool water were also positively correlated with turbidity. We recommended pool managers to limit the number of swimmers, advise swimmers that they wash their body before swimming to reduce the amount of organic compounds, and strengthen the function of filtration system to decrease turbidity.