加氯消毒為室內游泳池池水抑制微生物生長的主要管控方法，然而池水中的有機物質與水中餘氯所形成的消毒性副產物Disinfection by-products(DBPs），其中三鹵甲烷Trihalomethanes（THMs）被歸類於可能具有致癌性之物質，而游泳者在游泳池環境中活動中會因皮膚接觸以及呼吸與攝入等多重途徑暴露THMs。
本研究為了瞭解民眾在室內游泳池環境中活動時不同暴露途徑所造成的暴露差異，利用人體吐氣中的三鹵甲烷含量作為人員在環境中三鹵甲烷的暴露指標並以大專院校之游泳選手作為研究對象。研究中受試者分為三組並代表不同的暴露條件：岸邊活動人員代表室內游泳池室內空氣的背景暴露；穿著一般游泳衣游泳的受試者代表游泳過程中多重暴露途徑；穿著全身防水衣游泳的受試者代表僅受呼吸暴露。所有受試者分別在活動前後收集吐氣並分析其中三鹵甲烷濃度以了解暴露前後的差異，並比較各組受試者的暴露結果，以了解室內游泳池環境中THMs的主要暴露途徑為何。此研究亦對室內空氣樣本以及池水樣本進行採樣，人體吐氣樣本以及環境採集樣本皆以GC-MS進行分析。
所有環境樣本進行分析三鹵甲烷成分後僅檢測出三氯甲烷，進行分析受試者暴露前後的吐氣中三氯甲烷濃度後發現，進行游泳活動的受試者其暴露前後吐氣中三氯甲烷濃度變化皆有增加的現象並達到顯著差異性(p<0.05)；而在岸邊活動的受試者吐氣中三氯甲烷濃度並沒有發現顯著變化(p=0.7)，顯示人體在游泳過程中三氯甲烷暴露量大於岸邊走動。接著比較穿著一般泳衣的受試者與穿著防水衣隔絕水中皮膚暴露的受試者其吐氣中三氯甲烷變化量發現並無顯著差異(p=0.82)，顯示游泳過程中人體暴露三氯甲烷的主要暴露途徑可能來自於呼吸途徑。
Disinfection by chlorine is the major method to inhibit microbial growth in swimming pools. However, the organic matter in water will react with chlorine to disinfection by-products (DBPs), including trihalomethanes (THMs).
Trihalomethanes are classified as probable carcinogenic substances. During swimming in the pool, swimmers may exposed to THMs through multiple pathways, including contact with the skin, inhale from swimming pool air, and ingest of swimming pool water.
In this study, in order to understand that people exposure in the indoor pool, environmental monitoring of THMs in water and ambient air was performed. Biological monitoring of THMs by collect the concentration of THMs in exhaled breath to infer the relative internal dose received for the swimmers. Participants will be divided into three groups (wearing waterproof diving suit group, wearing normal swimming suit group, and non-swimmers group). To dissociate the different exposure route from dermal and inhalation, THM concentrations were measured in the alveolar breath of swimming subjects practicing in an indoor pool with and without by wearing waterproof diving suit.
After analyzing the composition of THMs in collected environmental samples, chloroform was the only chemical that can be detected in this study. The alveolar air sample from the subjects before and after 40 minutes of swimming activities were found that chloroform concentrations increased in exhaled air after performing swimming. In addition, the concentrations of chloroform in exhaled air before swimming are significantly different from those of after swimming (p <0.05). However, the concentrations of chloroform in exhaled air before and after swimming did not show significant variation in this study (p = 0.7). Then we compared the normal swimming suit group with wearing waterproof diving suit subjects whose skin is isolated to water. The results showed that the changes of chloroform concentrations before and after swimming in exhaled air samples for these two groups with no significant difference (p =0.82). It indicated that the concentrations of chloroform in exhaled sample due to exposure from skin pathway did not contribute significantly in this study. Therefore, we conclude that the main route of exposure is coming from the inhalation.
