Oxygen isotope chemistry of the water from Peshawar basin, Pakistan

Peshawar basin, a largest basin in the foothills of Himalayas, is drained by three major rivers i.e., Kabul, Swat and Indus and their tributaries. These rivers have greater impact on the agricultural, hydrological and environmental conditions of the basin. In order to identify the source of water and its environmental impact on the groundwater system of the basin, the oxygen isotopic ratios (O-18/O-16) of both surface and groundwater of the basin have been studied. Kabul, Swat and Indus rivers have distinct eft signature with Indus river being the most depleted (delta O-18 = -13.17), Swat being the most enriched (delta O-18 = -7.79) and Kabul river midway (delta O-18 = -11.4) between the two. The oxygen isotopic data for groundwater system of the Peshawar basin indicate that the aquifers in the Peshawar basin are recharged both by rainwater and waters from Kabul and Swat rivers. This study suggests that the surface and groundwater of the basin have most of the chemical parameters within the permissible limits at present. However, if these rivers turned polluted in future, their impact will certainly reach to deep levels in aquifers, especially in the vicinities of Kabul and Swat rivers.