The environment is polluted day by day and it is very much expensive to remediate the environmental pollutants by physicochemical process. Therefore, using plants as a process to remediate pollutants is essential. In this study, phytoremediation of root and leaf tissues of Indian mustard (Brassica juncea), rice (Oryza sativa) and wheat (Triticum aestivum) against three most environment pollutants viz. lead (Pb), chromium (Cr) and cadmium (Cd) of Buriganga riverbank soil of Dhaka city, Bangladesh were assessed. The highest amount of Pb was found in the leaf (11.6755 mg/kg dry weight) and root (51.4251 mg/kg dry weight) of B. juncea. However, the highest amount of Cr was found in the leaf (5.9871 mg/kg dry weight) of B. juncea; and in the root (46.4739 mg/kg dry weight) of O. sativa respectively. Although the highest amount (0.9624 mg/kg dry weight) of Cd was found in the leaf of B. juncea; the amount of Cd in the root was approximately same in all the three plants. This research also found more amounts of heavy metals compared to other studies using Indian mustard, rice and wheat against the three most environmental pollutants viz., Pb, Cr and Cd. Moreover, this study revealed that B. juncea is the highest hyperaccumulator species regarding Pb, Cr and Cd accumulation and can be used to clean up the polluted Buriganga riverbank soil.

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Buriganga, an economically important river of Dhaka, Bangladesh, is highly polluted by different toxic heavy metals. In this study, phytoremediation of EMS induced Indian mustard (Brassica juncea L) genotypes against three pollutants viz. lead (Pb), chromium (Cr) and cadmium (Cd) of Buriganga riverbank soil was assessed in field condition. Among 1-, 2- and 3% EMS induced genotypes, better seed germination rate, germination speed and plant survival rate were observed in 1% EMS induced genotype, BE21. The highest concentration of Pb, Cr and Cd were also obtained in the leaf of BE21 genotype and therefore was considered as a super-hyperaccumulator genotype. Concentration of Pb in the next generation of this genotype was approximately two-fold higher in the root (91.53 mg/kg dry weight, DW); three-fold higher in the shoot (33.31 mg/kg DW) and leaf (28.35 mg/kg DW), and more in the fruit (5.59 mg/kg DW) than the control. Concentration of Cr was approximately two-fold in the root (57.02 mg/kg DW), shoot (18.51 mg/kg DW) and leaf (14.98 mg/kg DW), and more in the fruit (6.15 mg/kg DW) of BE21 genotype compared to the control. Cd concentration was more in the root (1.96 mg/kg DW), leaf (0.52 mg/kg DW) and fruit (0.19 mg/kg DW) and less in the shoot (0.19 mg/kg DW) of BE21 genotype than the control. Root, shoot, leaf and fruit of BE21 altogether accumulated 98-, 73- and 87% Pb, Cr and Cd, respectively and can thus be utilized to remove heavy metals of Buriganga River. As like root, shoot and leaf, fruit also accumulated heavy metals; hence those plants which are used in phytoremediation should not be used as food or fodder. To the best of our knowledge, this is the first report of developing EMS induced hyperaccumulator genotype of B. juncea for phytoremediation of Buriganga riverbank soil of Bangladesh.