Title: Phytoremediation as a promising approach for reusing wastewater

Abstract

An excessive concentration 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 main wastewater channel of Soran City. Outdoor sand pot experiments were conducted in-situ and the selected macrophytes were applied. At the end of experiment, the macrophytes were harvested and prepared for heavy metal analysis using ICP-MS. The particular mechanisms of phytoremediation were 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 (bio-accumulation factor for roots, BAFroot >1 and translocation factor, TF 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.