Abstract

SARMIENTO, A. et al. Trihalomethanes in the drinking water of Carabobo State, Venezuela. Gac Sanit [online]. 2003, vol.17, n.2, pp.137-143. ISSN 0213-9111.

Objective: Disinfection of water with chlorine in water treatment plants leads to the formation of trihalomethanes (THMs). These compounds are associated with adverse health effects. The aim of this study was to analyze THM concentrations in the water provided for human consumption in the two main water treatment systems of Carabobo State: the Alejo Zuloaga plant and the Pao-Cachinche reservoir, which form the Central Regional System I (CRS I), and the Lucio Baldo Soules plant and the Pao-La Balsa reservoir, which form the Central Regional System II (CRS II). Methods: We analyzed 144 water samples collected in 6 samplings carried out in 2000 and 2001. THM concentrations were determined by gas chromatography using the headspace technique. The concentrations of the following THMs were measured: chloroform (CHCl₃), bromoform (CHBr₃), chlorodibromomethane (CHBr₂Cl) and bromodichloromethane (CHCl₂Br). Results: The concentration of total THMs was between 47.84 µg/l and 94.23 µg/l. CHCl₃ was the most commonly formed compound representing 83% of all THMs in the CRS I and 82% in the CRS II. The concentrations of total THMs in the CRS I, specifically in the Baja and San Diego networks, were significantly higher (p < 0.05) than permissible levels set by the American Environmental Protection Agency (80 µg/l) for the sum of all four THMs. Conclusions: The results show that in the area studied there is a risk of adverse health effects due to THMs in drinking water, especially in the Baja and San Diego networks.

Keywords : Chlorine; Disinfection; Trihalomethanes; Drinking water.

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