contamination and ecological risk assessment of heavy metals in surface soils of esfarayen city, iran

Background: the urban soil characteristic is very important since numerous people live in cities nowadays. in recent decades, heavy metals enter into the urban environment due to the urbanization and different activities in cities. these metal contaminations can pose serious threats on community health. contamination factor is a suitable tool for ecological geochemistry assessment. objectives: the current study aimed to determine the distribution and concentration of heavy metals (ni, pb, zn, cd, cu and cr) in soil from urban soils, assess the pollution level and potential ecological risk of heavy metals. methods: forty surface soil samples from different areas with different functions in five districts of esfarayen, iran, were collected and transferred to laboratory, after drying the samples at laboratory temperature, they were analysed to measure ni, pb, zn, cd, cu and cr using inductively coupled plasma optical emission spectrometry. results: the results showed the mean contents of cd, cu, cr, ni, pb and zn in soil of esfarayen were 0.21, 33.27, 39.9, 32.3, 25.2 and 106 mg/kg, respectively, which were more than the natural background content. the potential ecological risk index ranged from 21.0 to 651 with a mean value of 159. conclusions: among different functional areas, the industrial areas had the maximum metal concentrations. according to the potential ecological risk indices, industrial region and city squares in esfarayen have serious metal contamination and belong to the considerable pollution level. the results of the current study are very important for managers who define development strategies in cities and are also good to source pollution reduction.