Ecological risk assessment of potentially toxic elements (PTEs) in agricultural soils of western Iran using geochemical data and statistical analysis

Environmental pollution is a serious problem in many parts of the world, especially in developing countries such as Iran. This study was conducted to investigate chemical pollution by selected heavy metals in the southern cities of Hamadan province, west of Iran including Malayer, Toyserkan, and Nahavand. A total of 90 soil samples were collected from a depth of 0 to 30 cm of agricultural lands. The state of soil pollution was analyzed using geochemical indicators, pollution coefficient, pollution level, and potential ecological risk indices. The highest concentration of arsenic and cadmium in the soil of city of Toyserkan with an average of 19.46 and 0.25 mg kg-1 respectively, and the highest concentration of iron, cobalt, chromium, and antimony in the soil of city of Malayer with an average of 4.36, 20.8, 114.67 and 4.62 mg kg-1 respectively, and the highest concentrations of manganese, copper, and nickel in the soil of city of Nahavand were 268.95, 38.58, and 81.83 mg kg-1, respectively. The results showed that there was a significant difference between the average concentrations of the measured metals in the three cities. In all the studied cities, Mueller's geochemical index was in the non-polluted category, the pollution coefficient was in the low to medium pollution category, the pollution index was in the very low to high pollution category, and the environmental risk index for metals was in the low to very high environmental risk category. Investigation of pollution indicators showed that the soils of the studied areas are about to be polluted with heavy metals. Therefore, it is necessary to consider environmental aspects to reduce and prevent irreparable damage to the soil and the environmental cycle in the long run.