Geochemical assessment of vulnerability of groundwater to contaminant at phuoc hiep landfill site, Ho Chi Minh city, Vietnam

A geochemical assessment on vulnerability of groundwater quality and shallow aquifer in the vicinity of the Phuoc Hiep landfill site was carried out with a hydro-chemical approach for identifying various geochemical processes and understanding the impacts of landfill leachate on groundwater quality. Results indicate that hardness, nitrate, fluoride, iron in groundwater and heavy metal in surface water are above the standard for drinking water. Leachate seepage from the landfill is a main contaminant source of groundwater of Na-Cl water type with electrical conductivity (EC) values of 4,275 to 4,575 μS/cm. The pH values of the leachate are between 5.8 and 6.6. Concentrations of Al, Fe and Mn and heavy metals (Pb, Zn and Cu) in the leachate are above the drinking water standards. As a result, the waste leachate has a high content of contaminant that affects groundwater quality in highly productive zones. Two main zones of the aquifer were determined to be most vulnerable using GOD vulnerability model. Thus, these vulnerable zones are not suitable for waste disposal and the aquifer should be protected from leachate.