an investigation on as, cd, mo and cu contents of soils surrounding the meyduk tailings dam

the contents of as, cd, cu and mo were determined in soil surrounding meyduk tailings dam based on 21 surface soil samples. assessment of toxic element pollution in studied soil samples needs knowledge of pre-anthropogenic metal concentration to act as a reference against which measured values could be compared. estimating the background values was executed by sampling rocks adjacent to soil sampling stations. various indices including enrichment factor (ef), pollution load index (pli), modified contamination degree (mcd) and geoaccumulation index (igeo) were used for determining the contamination level of soil in the vicinity of tailings impoundment under the effect of the tailings dust. anthropogenic pollution was diagnosed from natural one by sequential extraction done by tessier et al. method and calculating pollution intensity index (ipoll). the results indicate a significant upward enrichment in northeastern and southwestern surface soil around the tailings dam for cd and cu. the dominant wind direction demonstrated that only the contamination of southwestern soil around the tailings dam would be attributed to tailings dust while the dispersive dusts scattered after the mine explosions generally affected the northeastern part.