Abstract
Heavy metal pollution is one of the negative impacts deriving from municipal solid waste landfills. Due to the multiple pollution transport pathways (including leachate, runoff, and waste gas) and complex and co-existing potential pollution sources (such as agricultural activities) around landfills, a combination of different pollution assessment methods and source identification tools are required to address pollution distribution and potential risks. In this study, the distribution of eight heavy metals (chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), arsenic (As), cadmium (Cd), and mercury (Hg)) around a landfill were analyzed using 60 topsoil samples. There are no environmental pollution and human carcinogenic risk posed by the heavy metals for the time being. However, high concentration of Cr in soil would cause non-carcinogenic risk for adults in the study area. Besides, the geo-accumulation indices of Cr, Cu, Ni, Zn, As, and Hg confirmed anthropogenic accumulation of these heavy metals in soils. Additionally, the potential ecological risk index indicated that Hg posed considerable risk to the eco-environment around the landfill. Sources of the heavy metals in the study area were attributed to natural sources (22.1%), agricultural activities (27.6%), and the landfill (50.3%). As the greatest contributor, the landfill affected heavy metal distribution in nearby surface soils mainly via surface runoff and waste gas. The continuous accumulation of heavy metals and non-carcinogenic risk for adults suggests the necessity for continuous monitoring of heavy metal content and migration around the landfill. This study provides a reference for local authorities in the study area.
Characterizing pollution and source identification of heavy metals in soils using geochemical baseline and PMF approach