An assessment of surficial aquifer vulnerability and groundwater pollution from a hazardous landfill site, Torbali/Turkey

Abstract

The Torbali River Basin is an important part of the Kucuk Menderes Basin in western Turkey, containing a highly productive alluvium aquifer. Hazardous waste from urbanization and industrialization has been stored above the main unconfined alluvial aquifer for the last five years. This study is intended to determine the surficial aquifer vulnerability characteristics and to assess the groundwater pollution mechanism from the hazardous landfill site that is located above the surficial aquifer. Two main vulnerable zones of the aquifer were determined using a GOD vulnerability model. The hazardous solid waste was dumped on a moderately vulnerable zone without any precautionary measure. Leachate seepage from the landfill is a main contaminant for NaCl water types with electrical conductivity (EC) values of 4,275 to 4,575 μS/cm. The pH values of the leachate are between 6.3 and 6.6. Concentration of As, Al, Fe, Mn, Ni, Sb, Se and Cd in the leachate are above and Pb, Zn and Cu concentrations are below the drinking water standards. As a result, the waste leachate has a high contaminant content that is causing groundwater pollution in a highly productive vulnerable zone. In this case, this vulnerable zone is not suitable for waste disposal activities, and some improvement studies should be done immediately to protect the main aquifer from the hazardous landfill site.