[Halogenated by-products of chlorination in tap water].

The presence of trihalomethanes in the water systems of several Spanish cities has been demonstrated. The aim of this study was to analyze trihalomethane concentrations in the water provided for human consumption in the city of Barcelona. We analyzed 151 water samples collected in 1998. The analyses were performed in the Public Health Laboratory of Barcelona using the purge-and-trap method and subsequent determination by gas chromatography and mass spectrometry. The results are presented according to the source of the water: the rivers of Llobregat or Ter, or a mixture of these. Trihalomethane concentrations in the water from Ter were relatively low, with a predominance of chloroform and bromodichloromethane, while concentrations in the water from Llobregat were much higher, with a predominance of bromoform and dibromochloromethane. Mixed water showed intermediate concentrations. The total concentrations reached in the water from Llobregat were above 100 microg/l. The results show the need to continue reducing organic pollution and halogenated compounds in the water used for human consumption in Barcelona.