pollution index and ecological risk of heavy metals in the surface soils of amir-abad area in birjand city, iran

conclusions it can be concluded that residential-road land uses show the considerable pollution index and ecological risk. materials and methods soil samples were collected from a depth of 0-20 cm at 16 stations with different users. the samples were passed through a 2-mm sieve after air drying. to determine the concentration of heavy metals, the samples were extracted by acid chloride and nitric acid and total concentrations of toxic elements were read using the atomic absorption spectrophotometry. the pollution index and ecological risk assessments were calculated for each element. background in the present era, the concentration of heavy metals in the environment is increasing. due to the deleterious effects of these metals on human health as well as their dangerous consequences on ecosystem, special attention should be paid to remove them from the environment. objectives the purpose of this study was to assess the ecological risk of heavy metals including lead (pb), cadmium (cd), copper (cu), zinc (zn), chromium (cr) in surface soils of an amir-abad area in birjand city, iran. results the results showed that the ecological risk of surface soil for the users of the road-residential was high (1370.72) and notable (505.04), and the agricultural land use and livestock had the moderate ecological risk and dairy farm had low ecological risk. when the results of this study were compared to world standards, it was suggested that the areas with the road-residential areas were considered to be dangerous to health; this was directly related to developments of technology and pollution.