survey of chloroform concentration in the water distribution system of isfahan, iran, and zoning by gis

background: the goal of this study was to survey the total residual chlorine and chloroform in the water distribution system of isfahan, iran, and zoning of obtained results using gis. methods: in this cross-sectional study, total residual chlorine was tested in the sampling points of the water distribution system of isfahan and chloroform was measured with standard methods and after transferring the samples to a laboratory under standard conditions. chloroform detection was done by gc-ms. the zoning of obtained results was performed by gis. findings: total residual chlorine and chloroform concentrations were obtained undetectable to 3.3 ppm and 10-28 ppb, respectively. high range of chloroform concentration was related to the end points of the water distribution system. moreover, the center of the city had a chloroform concentration less than other points. the reason for these problems could be more water consumption in central points of the city and stagnant water in other areas of the city. conclusion: the results of this study showed that the water production of the isfahan water treatment plant had an acceptable quality in relation to its cl - and dbps content, at the sampling time. the obtained concentrations followed the who and usepa guidelines. however, it is necessary to detect probable concentration of thms production, continuously. furthermore, by using integrated and appropriate water treatment methods, dbps can be reduced considerably.