Phytoremediation Perspectives of Seven Aquatic Macrophytes for Removal of Heavy Metals from Polluted Drains in the Nile Delta of Egypt

SIMPLE SUMMARY: Some main drains in the Nile Delta of Egypt are subjected to heavy pollution loads and used to irrigate crops and vegetables. Here, we assessed the pollution level and the ability of some wild aquatic macrophytes (Cyperus alopecuroides, Echinochloa stagnina, Eichhornia crassipes, Ludwigia stolonifera, Phragmites australis, Ranunculus sceleratus, and Typha domingensis) to accumulate eight heavy metals (Fe, Cu, Zn, Mn, Co, Cd, Ni, and Pb) in three of the polluted drains (Amar, El-Westany, and Omar-Beck). The sediment in the three drains exceeded the worldwide permissible ranges of Cu, Zn, and Pb, but it ranged within safe limits for Mn, Cd, Ni, and Co. P. australis accumulated the highest levels of Fe, Co, Cd, and Ni, while E. crassipes contained the highest concentrations of Cu, Zn, Mn and Pb. The bioaccumulation factor was > 1 for the investigated heavy metals (except Cu) in all species, except C. alopecuroides. Accordingly, these species could be applied for the accumulation and phytostabilization of these metals. ABSTRACT: The current study addressed the heavy metals accumulation potentials of seven perennial aquatic macrophytes (Cyperus alopecuroides, Echinochloa stagnina, Eichhornia crassipes, Ludwigia stolonifera, Phragmites australis, Ranunculus sceleratus and Typha domingensis) and the pollution status of three drains (Amar, El-Westany and Omar-Beck) in the Nile Delta of Egypt. Nine sites at each drain were sampled for sediment and plant analyses. Concentrations of eight metals (Fe, Cu, Zn, Mn, Co, Cd, Ni, and Pb) were determined in the sediment and the aboveground and belowground tissues of the selected macrophytes. Bioaccumulation factor (BF) and translocation factor (TF) were computed for each species. The sediment heavy metals concentrations of the three drains occurred in the following order: El-Westany > Amar > Omar-Beck. The concentrations of sediment heavy metals in the three drains were ordered as follows: Fe (438.45–615.17 mg kg(−1)) > Mn (341.22–481.09 mg kg(−1)) > Zn (245.08–383.19 mg kg(−1)) > Cu (205.41–289.56 mg kg(−1)) > Pb (31.49–97.73 mg kg(−1)) > Cd (13.97–55.99 mg kg(−1)) > Ni (14.36–39.34 mg kg(−1)) > Co (1.25–3.51 mg kg(−1)). The sediment exceeded the worldwide permissible ranges of Cu, Zn and Pb, but ranged within safe limits for Mn, Cd, Ni and Co. P. australis accumulated the highest concentrations of Fe, Co, Cd and Ni, while E. crassipes contained the highest concentrations of Cu, Zn, Mn, and Pb. Except for C. alopecuroides and Cu metal, the studied species had BF values greater than one for the investigated heavy metals. Nevertheless, the TFs of all species (except Cd in L. stolonifera) were less than one. Hence, the studied species are appropriate for accumulation, biomonitoring, and phytostabilization of the investigated metals.