Ecological risk assessment and distribution of heavy metals (Pb, Cr, Ni, as, Co and Mn) in soil of Douroud city, Iran

Urban soil plays a unique role in the health and development of the ecosystem. The quality of the environment in urban areas, specifically industrial and semi-industrial cities, is seriously affected by heavy metal pollution. In this study, the streets of the city of Douroud were zoned, and 30 topsoil samples were collected. Then, while determining the concentration of heavy metals, their ecological risks were assessed. Geoaccumulation index, enrichment factor, pollution Index, and Modified Risk Index (MRI) indices were evaluated according to EPA standards. The percentage of nickel, chromium and lead samples were higher than the international standard, 83.3, 50 and 26.6, respectively. The results showed that among the 6 trace elements evaluated, the average concentration of nickel is higher than the standard. The average enrichment factor of nickel) Ni), Chrome (Cr), arsenic (As), manganese (Mn), and cobalt (Co) is 1.6, 1.25, 0.88, 1, and 0.8, respectively, and lead with an average of 3. 1. It has moderate enriched. And the contamination of heavy metals, especially nickel, lead, and chrome, around the cement factory and ring road is far more than other streets and needs more environmental attention.