COMPARISON OF METHODS FOR DETERMINATION OF TRIHALOMETHANES IN DRINKING WATER

SUKEO ONODERA, CHERDCHAN SIRIWONG, AND MONTHIP TABUCANON

ABSTRACT: Comparison of 2 methods (head space analysis and liquid-liquid extraction methods) were carried out in this work for determination of trihalomethanes (THMs) in drinking water supplies in Bangkok. Both methods are applicable for determination of the haloform concentrations ranging 0.1 to 200 g/l. Sampling apparatus and procedure for both head space analysis and liquid-liquid extraction methods are very simple. and easy, but possible disadvantages for liquid-liquid extraction are its somewhat low sensitivity and time consumption because the co-extracted non-volatile compounds require several minutes to be eluted from the column with late analysis. A priminary survey for THMs in drinking water supplies in Central Bangkok Metropolitan was conducted using head space analysis. The survey demonstrated that trihalomethanes, chloroform, bromodichloromethane, and dibromochloromethane were found in drinking water supplies obtained from the surface water, but none of these chemicals was detected in the chlorinated water from groundwater. The range of total concentrations of trihalomethanes detected was 25 to 75 g/l and the mean value was 44.9 g/l.

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Environmental Quality Standard Division. National Environment Board, Rama 6 Rd., Bangkok 10400, Thailand

Received 14 September 1984