Correlation Study and Regression Analysis of Drinking Water Quality in Kashan City, Iran

Chemical and statistical regression analysis on drinking water samples at five fields (21 sampling wells) with hot and dry climate in Kashan city, central Iran was carried out. Samples were collected during October 2006 to May 2007 (25 - 30 °C). Comparing the results with drinking water quality standards issued by World Health Organization (WHO), it is found that some of the water samples are not potable. Hydrochemical facies using a Piper diagram indicate that in most parts of the city, the chemical character of water is dominated by NaCl. All samples showed sulfate and sodium ion higher and K + and F - content lower than the permissible limit. A strongly positive correlation is observed between TDS and EC (R = 0.995) and Ca 2+ and TH (R = 0.948). The results showed that regression relations have the same correlation coefficients: (I) pH -TH, EC -TH (R = 0.520), (II) NO 3 - -pH, TH-pH (R = 0.520), (III) Ca 2+ -SO 4 2- , TH-SO 4 2- , Cl - -SO 4 2- (R = 0.630). The results revealed that systematic calculations of correlation coefficients between water parameters and regression analysis provide a useful means for rapid monitoring of water quality.