| Summary: | 碩士 === 中國醫藥大學 === 公共衛生學系碩士班 === 101 === 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.
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