ABSTRACT

ABSTRACT: The study of the hydrogeochemical processes in the vicinity of Bhalswa landfill was carried out with an objective to identify the geochemical processes and its relationwith groundwater quality besides understanding the impact of landfill leachates on groundwater quality and to get an insight into the hydrochemical evaluation of the aquifer system. The various graphical plots and statistical analysis has been carried out using chemical data to deduce a hydrochemical evaluation of aquifer system based on the ionic constituents, water types, hydrochemical facies and factors controlling groundwater quality from May 2003 to January 2005. Total thirty three groundwater samples were collected from shallow and deep aquifers around the landfill covering an area of 15 km2. Groundwater sampling was carried out twice during pre-monsoon and postmonsoon seasons each in these periods. The study also reveals the suitability of groundwater for irrigation and drinking purpose as well as water quality variation of groundwater. The contour line around landfill indicates that the landfill is a point source of pollutant. Geology of study area is mainly made up of alluvium; there is a high probability of leaching of pollutant into groundwaters. The concentrations of metal contaminants in the landfill leachates are generally high with maximum concentrations of Fe (∼22 mg/L), Mn (∼20 mg/L), Cu (∼10 mg/L), Pb (∼2 mg/L), Ni (∼0.25 mg/L), Zn (∼10 mg/L), Cd (∼0.2 mg/L). The concentration of the major ions such as Cl− (∼4000 mg/L), SO2−4 (∼3320 mg/L), PO3−4 (∼4 mg/L), NO−3 (30 mg/L) and F− (∼50 mg/L) were also much higher than the regulatory standards. The study reveals that landfill is in depleted phase and it is affecting groundwater quality in the vicinity of landfill and surrounding area due to leaching of contaminants and posing a serious threat to the groundwater in the adjoining areas.