Integration of water pollution indices and DRASTIC model for assessment of groundwater quality in El Fayoum depression, western desert, Egypt

Groundwater is an important water resource in Egypt for many purposes. Heavy metal pollution index (HPI), heavy metal evaluation index (HEI), pollution index (PI) and DRASTIC model were used to assess the ground-water quality and the aquifer vulnerability in El Fayoum depression, Western desert, Egypt. Depths to groundwater surface were measured in 27 observation wells. Groundwater samples were collected from 38 wells of depths less than 60 m. Physiochemical parameters; pH, TDS, EC, Al, Ba, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Sb and Se, of the collected samples were measured using standard analytical methods. Multivariate statistical analysis and GIS techniques were used for processing the obtained results. The HPI results indicated that 74% of groundwater points have HPI values exceed the critical pollution level. The HEI values indicated that the majority of the groundwater samples are affect by heavy metal pollution. The PI values revealed that the groundwater samples are slightly affected by Pb and Sb, and are moderately affected by Se. The vulnerability index (VI) results, which were calculated by DRASTIC model, revealed that the groundwater aquifer vulnerability increases radially from the depression center to the peripheries of the study area. An agreement is revealed from comparison of spatial distribution maps of HPI, HEI and VI results. The integration between water pollution indices and DRASTIC model is a valuable and applicable approach for assessment of groundwater quality using physiochemical parameters of the groundwater and the aquifer characteristics.