This study aims to assess the extent of metal accumulation by plants found in a mining area in Hamedan Province in the central west part of Iran. It also investigates to find suitable plants for phytoextraction and phytostabilization as two phytoremediation strategies. Plants with a high bioconcentration factor (BCF) and low translocation factor (TF) have the potential for phytostabilization while plants with both BCFs and TFs greater than one have the potential to be used for phytoextraction. In this study, shoots and roots of the 12 plant species and the associated soil samples were collected. The collected samples were then analyzed by measurement of total concentrations of trace elements (Pb, Zn, Mn and Fe) using atomic absorption spectrophotometer. Simultaneously, BCF and TF parameters were calculated for each element. Results showed that although samples suitable for phytoextraction of Pb, Zn, Mn and Fe and phytostabilization of Fe were not detected, Scrophularia scoparia was the most suitable for phytostabilization of Pb, Centaurea virgata, Echinophora platyloba and Scariola orientalis had the potential for phytostabilization of Zn and Centaurea virgata and Cirsium congestum were the most efficient in phytostabilization of Mn. Present study showed that native plant species growing on contaminated sites may have the potential for phytoremediation.

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Environmental risk assessment is a step towards identification, analysis, and classification of risk factors and thus reduction of the possibility of adverse consequences. In this research, a novel approach for environmental risk assessment on groundwater pollution is applied. By combination of aquifer vulnerability DRASTIC map, pollution severity and prioritizing of the plain regions by the TOPSIS method, more sensitive regions of Qazvin aquifer in Iran are identified. In the first step, seven hydro-geological characteristics of the aquifer are overlaid to produce the potential vulnerability map. Nitrate is used as the pollution parameter and its value in monitoring wells is measured by sampling. Spatial distribution of nitrate concentration is investigated using the ordinary kriging method. The TOPSIS ranking method is also applied to estimate the probability of occurrence of pollution based on five affecting criteria defined and quantified in regions of the aquifer. By production of these three layers, the risk map of the aquifer is generated. Results indicate that 9% of the area of the aquifer is categorized in the high risk level which needs an emergency recovery action plan. Also, sensitivity analysis on the parameters of the aquifer vulnerability shows the effect of the soil media more than other parameters.

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