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Heavy metals have ecological importance due to enter into food chain. In this study, in order to investigate the heavy metal pollution status and the effect of the dominant plant in Gelerood river, the concentrations of heavy metals Pb, Zn and Cu were investigated in sediment and plant species of Phragmites australis. Then, the Bioconcentration Factor (BCF) and the Translocation Factor (TF) were used to investigate the phytoremediation potential. Samples were collected from sediment, root and leaf in five stations with three replications in autumn of 2014. The results showed that the mean concentrations of Cu, Pb and Zn in aboveground organs of plants were 7.4, 11.17 and 11.87 (in μg/g of dry mass), respectively, and in the underground organs of the plant were 6.71, 9.29 and 17.81 (in μg/g of dry mass), respectively. In addition, the mean concentrations of Cu, Pb and Zn in sediment samples were 16.2, 7.5, and 41.77 (μg/g), respectively, that the concentrations of heavy metal in sediment were relatively lower than toxicity level. The result indicates that the heavy metals are not serious contamination for the living organisms of the region. Based on the results, the mean BCF of underground organs were 1.32 (Pb), 0.41 (Cu), and 0.42 (Zn), respectively, and for the aboveground organs were 1.49 (Pb), 0.45 (Cu), and 0.28, respectively. According to BCF result, P. australis is known as a hyper-accumulator plant for Pb, and the plant is known as an accumulator plant for Cu and Zn. In addition, the mean TF for Pb, Cu, and Zn were 1.2, 1.11, and 0.66, respectively. The results show that the value of the TF in relation to Pb and Cu is greater than 1, which indicaes the effective role of roots in transferring these metals to different parts of the plant. According to the coefficients of indexs, Phragmites australis are recommended for the phytoextraction of Pb and Cu, and the phytostabilization in relation to Zn metal in the study area.

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Aquatic plants have a high and different capacity to absorb heavy metals. Therefore, their use is recommended as an inexpensive and environmentally friendly method to remove metals from contaminated environments. In this study, accumulation, bio-concentration and transfer factors of two heavy metals nickel and cadmium by three plant species Scirpus tabernaemontani, Phragmites australis and Typha latifolia by applying three levels (nickel with levels of 20, 50 and 150 mg/kg and cadmium levels of 10, 35 and 85 mg/kg) cultured in pot culture medium with a sandy bed for 60 days in winter of 2017 were studied. After preparing the substrate, adding nutrient chemicals and concentrating the substrate to the studied metals, each culture medium was randomly assigned to one treatment in three replications. The results showed that the effect of different levels of concentration of both metals and type of aquatic plant on accumulation in plant organs was significant. Also, the accumulation of the two studied metals in the underground organs was far more than the same values in the aerial organs. Maximum amount of nickel accumulation was observed in underground and aerial organs related to Typha latifolia with values of 71.6 and 35.8 mg/kg and 34.6 and 12.5 mg/kg in dry matter for cadmium. The highest transfer factor about nickel and cadmium were recorded for Typha latifolia with values of 0.44 and 0.34. In terms of bio-concentration factor, Phragmites australis and Typha latifolia with values of 0.68-0.78 and 0.71-0.84 for cadmium, and 0.48-0.70 and 0.58-0.70 for nickel are in ranges are considerable. Due to the fact that the present experiment was conducted in the warm season in Khuzestan, due to the high air temperature, high evapotranspiration of aquatic plants can be a good reason to absorb more heavy metals.