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

Abstract

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-aquatica L.; Mentha longifolia L. (Hudson) and Cyperus iria L. and one free-floating; Nasturtium officinale R. 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-aquatica and C. 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 by C. iria (>1000 mg/plant root), BAFs > 1, and TF < 1, and the revealed mechanism was phytostabilization. Mentha longifolia accumulated similar patterns of Zn in shoots and roots (BAFs >1 and TF >1), the involved mechanism was phytoextraction. Free-floating N. officinale showed the highest percentage of metal uptake and removal capacity for Pb (∼60% and ∼10 mg/d/g, respectively). Synergetic and plant genetic abilities need to be optimized to develop commercially useful practices.

Keywords:

• Accumulation
• hyperaccumulator
• removal capacity

Disclosure statement

No potential conflict of interest was reported by the author(s).