Evaluating trihalomethanes in tap water and swimming pool water at Ho Chi Minh city

Abstract

Trihalomethanes (THMs) are byproducts of the process of disinfecting water with chlorine, in which, 4 compounds are most interested such as chloroform (CF), bromodichloromethane (BDCM), dibromochloromethane (DBCM) and bromoform (BF). These DBPs even at very low concentrations pose harmful health effects. These health risks may include cancers, reproductive disorders, birth defects and miscarriage. This study evaluates the  4 THMs in water supplied at 6 districts of Ho Chi Minh City and in swimming pool water at Tan Binh district. All samples were extracted by using liquid- liquid extraction method with n-hexane: diisopropylether (1:1) before analyzing by GC-ECD. The results showed that 4/4 THMs were found in water samples and 2/4 THMs (chloroform and bromodichloromethane) were found in swimming pool water samples. The results showed that there are differences in the THMs levels between sampling site. The average concentration of THMs in supplied water was 31.40 ±29.23 µg.L^-1 (20 – 110 µg.L^-1), in swimming pool water was 109.78 ± 15.21 µg.L^-1 (90 – 140 µg.L^-1). The sampling site which has the highest average concentration is Tan Phu district (102.45 ± 16.0 µg.L^-1) and the lowest is district 1 (23.74 ± 1.92 µg.L^-1). The results showed that the concentration of THMs in the supplied water and swimming pool water does not exceed the limit of national technical regulation on drinking water quality (QCVN 01: 2009/BYT), however, the  chloroform concentration of some sampling sites exceeds the limit given by the Environmental Protection Agency (EPA).