Authors: Ricardo Andreola, Péricles Martim Reche, Gervasio Tono,
Graciene de Souza Bido, Daniele Fernanda Felipe, Anny Rosi Mannigel,
André Ribeiro da Costa, Gisele Caroline Novakowski, Letycia Lopes Ricardo,
Flavia Helena de Moura Liborio, Stephane Raquel Almeida Velande da Fonseca,
Isabela Silva de Oliveira, Giuliano Patrick Rasera, Thaise Moser Teixeira
Chlorination is an efficient and low-cost technique in disinfecting water for public water supply. However, during the process, the formation of undesirable by-products called halogen compounds, such as trihalome-thanes (THMs), occurs. Some of these compounds are proven to be carcinogenic to laboratory animals. The goal of this study was to investigate the occurrence of THMs in household reservoirs and the influence of cleaning time of these reservoirs on the formation of THMs. A total of 103 households were investigated in the city of Maringá, State of Paraná, Brazil. The residences were classified according to the cleaning time of the reservoir into: up to one year, one to two years and more than two years. Samples were taken from the reservoirs and total trihalomethanes (THMt) were analyzed by gas chromatography (GC-MS), total organic carbon (TOC) by means of a Hach kit for low concentrations and free residual chlorine (CLres) by means of a kit for in loco determination. According to the results, the highest concentrations of THMt were observed in the reservoirs with cleaning time of more than 2 years. However, no amount has exceeded the maximum limit allowed by law. In general, the longer the time for cleaning the reservoir, the greater the degradation of water quality in THMt.
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