The evaluation of ground water pollution in alluvial and crystalline aquifer by Principal Component Analysis

In order to evaluate the groundwater pollution, the application of statistical principal components analysis (PCA) was used as one useful tool. PCA was based on the physicalchemical data of groundwater samples in the aquifers. Three components were obtained in the study area. PC -1 accounts for 36% of the total variance due to the high loadings in Na, CI, Ca, Mg, and HC03. PC -2 represents 24% of the total variance and shows high loadings for SSP, K Ratio, SAR and Na % and PC -3 is dominated by high loadings in K and S04. The principal components analyses indicate water-rock interaction process as the major mechanism responsible for the groundwater salinity (mainly sodium-bicarbonate type), invoking the lithological composition dominated by feldspathic mineral group. This analysis led to the conclusion is two major sources of contamination playa major in the groundwater pollution in the area: fertilizers, pesticides and insecticides used in agricultural activities, and non-point natural sources.