| Summary: | 碩士 === 國立臺灣大學 === 環境衛生研究所 === 100 === Chlorination is an important treatment at swimming pools. With human-introduced compounds, various disinfection by-products (DBPs) might be formed. Among the DBPs, trichloramine appears as gaseous form in the atmosphere at indoor swimming pools. Levels of trichloramine, and its health concerns among simmers and lifeguards at indoor swimming pools have been studied in many countries previously. The purpose of this study was then to describe the scenario of trichloramine exposures at indoor swimming pools in Taiwan and to discover the factors affecting the levels of trichloramine.
In this study, sampling and analysis method for airborne trichloramine was set up according to the methods published elsewhere. The trichloramine air sampler was composed with two components: the first one was 6mL cartridge tube filled with sulphamic acid coated silica gel, and the second one was 37mm sampling cassette with diarsenic trioxide and sodium carbonate coated quartz fiber filters. It was an active air sampling method, and the air flow rate was set at 1L/min. After sampling, the quartz fiber filter was desorbed by 10mL ultrapure water and further analyzed by ion chromatography. Questionnaires were administrated in this study and the information about swimming pool maintenance was also collected.
Ten indoor swimming pools in Taipei were included for field sampling. Concentrations of trichloramine were found to be ranged from 0.017 to 0.15mg/m3 (total of 78 samples). For the pool workers who completed the questionnaire, 51 out of 104 were male, and 48 of them were lifeguards. Among the reported prevalence of respiratory symptoms at work, experiencing eye irritation and cough were the highest. Besides, symptom of sore throat and phlegm were more likely to happen among the high-exposed group (i.e., lifeguards and swimming instructors) than the low-exposed group (odds ratio ranged from 1.44~88.33 and 1.16~15.4 for sore throat and phlegm, respectively).
On the other hand, the concentrations of free available chlorine (FAC) in pool water and the number of swimmers were significantly associated with the levels of airborne NCl3 (p-value= 0.003). It is suggested that the regulated FAC levels in different countries may cause the concentrations of trichloramine reported elsewhere to be nonidentical.
To lower the level of trichloramine at indoor swimming pool, well-functioned filtration and ventilation systems as well as hygiene code for swimmers are necessary. Changing parts of pool water regularly is also an efficient way. The relatiohship between the FAC value and the airborne trichloramine level should be further concerned.
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