Risk of soil and water pollution by heavy metals in landfill leachate.

Abstract

Environmental pollution due to landfill leachate has been studied extensively for inorganic and organic pollutants. This study investigates the risk of soil and water pollution by heavy metals in leachate from a selected landfill in Gampola, Sri Lanka. Leachate and soils from the landfill were collected and analyzed for heavy metals. The results reveal that the heavy metal concentrations in leachate is relatively low and highest quality rating scales of 620, 108 and 74 % were resulted for Cd, Pb and Cr, respectively. Heavy metal concentrations in soils were higher than that of leachate and showed a decreasing trend with increasing distance from the landfill. The highest content of Cd, Mn and Cu were 21,173 and 2493 mg kg-1, respectively at the landfill whereas highest content of Zn, Ni, Pb and Cr (1619, 76, 1003 and 239 mg kg-1, respectively) was found within 1 m distance from the dumpsite. Interestingly, Lead, Cadmium, Copper and Zinc were exceeded the Sri Lankan standards limits of heavy metals for compost. Moreover, heavy metals in soil samples showed higher concentrations than concentrations in leachate. The concentrations of 0.038, 0.14 and 0.037 mg L-1 were resulted for Cd, Pb and Cr, respectively in landfill leachate. It can be concluded that the soils are highly contaminated with heavy metals from landfill leachate indicating the potential of the soils to be a natural attenuating agent. However, when the soils’ capacity exceeds there is a possibility of ground and surface water contaminations by heavy metals in landfill leachate.