An Assessment of Water Quality and Classification in Karaj River

Water quality index (WQI) is a mean to summarize large amounts of water quality data into simple terms for reporting to decision makers and the public in a consistent manner. In this study, the quality of water in 9 sampling stations with respect to ten water quality parameters(pH,EC,TDS,Nitrate,Nitrite,COD,Turbidity,Sulfate,Total coliforms,Fecal coliform) was considered. Cluster analysis was utilized to separate the stations based on the levels of pollution and the classification of stations was implemented by Naïve bayes classifier method.The overall quality of water was studied by water quality index and the associated health risk of nitrate and nitrite was investigated through hazard quotient calculations.The results indicated that misclassification error of Naïve bayes for the two groups created by cluster analysis were 0,0.33 and 0.66 for the training,2-fold and hold-out cross-validation methods,respectively.The WQI results showed that the quality of water was between permissible and slightly polluted. The health risk of nitrate was higher than nitrite and for children was higher than that of adults, accordingly.However, even though, since the hazard quotient was lower than one so,there is not any immediate threat due to the consumption of water at the moment.