Characterizing Changes of Heavy Metals in the Soils from Different Urban Location of Borujerd, Lorestan Province, Iran

Abstract

As more people live in cities and urban areas, evaluation of urban environmental quality is nowadays an unavoidable necessity. Urbanization gives off heavy metals into urban soils and threatens the human health. In this study, urban soil samples were acquired from different locations (Public parks, streets, and squares) from Borujerd, Iran. The levels of Cd and Pb in the soils, along with soil pH, electrical conductivity (EC), and particle size distribution (texture), were analyzed. Kriging method by Surfer software was employed to create the spatial distribution maps of Cd, Pb, and geoaccumulation index (Igeo). The average Cd and Pb concentrations in the surface soil samples were 2.50±1.14, and 50.37±34.77 mg/kg dry weight, respectively. The highest mean concentration of Cd was found in street soils and as for Pb in square soils. The interpolation maps illustrated the same behavior for Cd and Pb with elevated concentrations located in the southeast. The mean values of geoaccumulation index (Igeo) showed that soils are moderately/strongly contaminated with Cd and moderately contaminated with Pb. In this study, traffic emission, textile industries and probably released untreated municipal wastewater into the soil are anthropogenic sources of Pb and Cd.