Native aquatic plants for phytoremediation of metals in outdoor experiments: implications of metal accumulation mechanisms, Soran City-Erbil, Iraq

An excessive amount of metals is toxic to plants, animals, and humans. The present study focuses on the efficacy of three local emergent aquatic plants;Veronica anagallis-aquaticaL.;Mentha longifoliaL. (Hudson) andCyperus iriaL. and one free-floating;Nasturtium officinaleR. Br. for removal of metals (Fe, Pb, Zn, Cu, Mn, and Ni) from the wastewater, in outdoor sand pot experiments. The particular phytoremediation mechanisms were also investigated. The selected plants adapted and properly grew, as determined by their high biomass production and survival rate. Emergent plants (V. anagallis-aquaticaandC. iria) accumulated high quantities of Fe, Cu, Ni, and Mn in roots (bioaccumulation factor for roots, BAF(root)>1 and translocation factor, TF <1), therefore credited as strong excluders. The highest concentration of Fe was taken up byC. iria(>1000 mg/plant root), BAFs > 1, and TF < 1, and the revealed mechanism was phytostabilization.Mentha longifoliaaccumulated similar patterns of Zn in shoots and roots (BAFs >1 and TF >1), the involved mechanism was phytoextraction. Free-floatingN. officinaleshowed the highest percentage of metal uptake and removal capacity for Pb (similar to 60% and similar to 10 mg/d/g, respectively). Synergetic and plant genetic abilities need to be optimized to develop commercially useful practices.

Automated summary

This study evaluated the efficacy of local aquatic plants in removing metals from wastewater. Different plants showed different capacities in accumulating or extracting metals, indicating the need for optimized strategies for commercial applications.