Groundwater pollution with special focus on arsenic, Dera Ghazi Khan-Pakistan

Thirty-two representative samples of groundwater collected randomly from Dera Ghazi Khan (City)-Pakistan were analyzed for physical and chemical quality parameters with special attention to life threatening parameter arsenic (As). The arsenic (As) concentration in groundwater of study area was found from 1 to 29 µg L^-1, which lies in the satisfactory range recommended by WHO (i.e. 10 µg L^-1), for most of the samples examined except for few ones. This mild enrichment of Arsenic in few sites/wells is the result of most probably microbial contamination, metal leaching from the mine wastes and reduction of hydrous ferric oxide (HFO). The arsenic (As) trend with respect to physicochemical water quality parameters was observed during the study. Apart from arsenic (As), physical parameters (pH, EC, TDS, turbidity) and chemical parameters (alkalinity, CO3, HCO3, Cl, F, NO3, SO4, Na, K, total hardness (TH), Ca, Mg and microbial contamination) of potential concern for drinking water were estimated by using analytical techniques. Electrical conductance (EC) and total dissolved solids (TDS) values of groundwater were extremely high from WHO guideline values with no appreciable change in pH values for virtually all samples. Likewise, the chemical quality of groundwater samples also goes beyond the WHO guideline values for parameters such as chlorides, sulfates, sodium, calcium, magnesium and total hardness (TH). During the study it was discovered that the tropical or geographical reason works well behind this undesirable chemical behavior of groundwater.