Isotopic and hydrochemical study of the effect of tannery effluents on groundwater quality in Kasur area

Isotopic and conventional techniques were employed to study groundwater recharge mechanism, and the effect of tannery effluents on the quality of groundwater in Kasur area. Water samples were collected from hand pumps, deep wells and pond water. The physico-chemical parameters were measured in the field and stable isotopes of H/sup 2/ and O/sup 18/ were analysed by using GD-150 gas source isotope ratio mass spectrometer. Depleted isotopic contents of delta H/sup 2/ and delta O/sup 18/ characterize canal recharge, enriched isotopic values are associated with rain recharge and intermediate values show the mixing of water from different sources. The shallow groundwater has depleted isotopic values and is being recharged by the canal. However, isotopic signature of shallow groundwater in the surroundings of the pond has been modified by the seepage of the pond water. The deuterium excess values are low showing the effect of evaporated pond water and these values increase as the distance from the pond increases. Electrical conductivity values and chloride contents decrease along the depth. The deep groundwater that can be termed as the native groundwater is being recharged by rains at piedmont area/bedrock outcrops. Results indicate that the quality of shallow groundwater has been deteriorated in the vicinity of stagnant pond water but quality of deep groundwater is good. Chromium is absent in groundwater, its penetration is limited up to a maximum depth of 10 meters. (author)