Environmental monitoring and ecological risk assessment of heavy metals in farmland soils

This study aimed to investigate the concentration of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, and As) and assess their ecological risk in agricultural soils of Kamfiruz district, Fras, Iran. Index of geo-accumulation (Igeo), Contamination Factor (CF), Pollution Index (PI), and Ecological Risk Index (RI) were used to assess the contamination status. Igeo indicated that the soil was not contaminated by Cr, Cu, Ni, Pb, and Zn, but was moderately contaminated by Cd and As. Moreover, CF revealed a low contamination range for Cr, Ni, and Pb and a moderate range for Cu, Zn, and As. The study area was remarkably contaminated by Cd based on the CF index. The PI index showed that Pb, Ni, and Cr with the PI values of 0.98, 0.61, and 0.98 fell into the “low contamination” category, Cu, Zn, and As fell into the “moderate contamination” class, and Cd fell into the high contamination category. RI showed a low potential ecological risk for the presence of heavy metals in the study area. Overall, the results showed that Cd was responsible for the highest level of contamination, which could be due to human activities such as using chemical fertilizers and pesticides in the soil of the study area.