Heavy metal pollution index for groundwater quality assessment in Damascus Oasis, Syria

Heavy metal pollution index (HPI), is a rating method and an effective tool to assess the water quality with respect to heavy metals. Twenty-seven groundwater samples were collected from the municipal drinking water supply in Damascus Oasis. The metals such as cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) were considered. The metal concentrations showed a dominance in the order of Zn > Cu > Pb > Cd, respectively. The value of HPI based on the mean concentration was found to be 8.58, which is far below the critical pollution index value of 100. Most of the groundwater samples (74 %) have an HPI lower than the mean value of 8.58. Whereas, 26 % of the samples exceed this mean and only one sample reaches the limit of low pollution by heavy metal. Spatial distribution of HPI is in well agreement with the metals’ spatial distribution and showed the high values of HPI in the south eastern part of Damascus city to the center and especially in the northeastern part of the study area. This indicates the effect of industrial zone, agriculture and urban activity. It indicated that the groundwater at the northeast of the studied area is likely affected by leaching of heavy metal from the sewage water treatment station.