Evaluation and Statistical Analysis of Groundwater Quality Parameters and Index for Drinking in Khorramabad Region

The statistical methods are used for investigation of water quality in different area that such as univariate and multivariate statistics methods. In the study area, according to cluster diagrams of groundwater quality parameters are plotted in two cluster that due to formations and geological factors. Principle component analysis methods are shown that effective factors such as electrical conductivity, material solution, HCO3-, Mg2+, Cl-, Na+ and total hardness in groundwater quality. According to major parameters and its source, groundwater quality related to geological formation, limestone and evaporated rocks in the study area. The coefficient factor of groundwater parameters in the study area are shown that high relationship between electrical conductivity with SO42-, Na- and Cl- due to halite solution from Ghachsaran formation and high correlation between electric conductivity and SO42- ,Na+,Cl- due to sulfate salt and sulfate calcium especially. Also correlation between HCO3- and Mg2+ can be considered for role of dolomite rocks solution in increasing Ca2+ concentration in water. The GQI of groundwater quality in the study area is evaluated that indicated groundwater quality of region are between 73% to 81%, which indicate the groundwater quality placed in suitable to acceptable class of quality that may be affected by geological factors such as lithology, current direction in the area. The correlation between groundwater quality index and quality parameters are shown that total hardness, bicarbonate and dissolved solids had the highest impact on groundwater quality in the study area.