Cyperus longus to bioremediate heavy metals in aqueous solutions

Finding environmentally friendly methods for the bioremediation of the environment, including water, contaminated with heavy metals is of utmost significance. The ability of 50 Cyperus longus species, harvested from Shadegan International Wetland, Iran, for the phytoremediation of heavy metals in contaminated water was investigated. The plants were transplanted in the aquariums contaminated with one of the heavy metals (0-20 mgL-1) at the pHs of 4 and 7 for 30 days. Plant removal of heavy metals was determined. The single and double interactions of plant tissue, heavy metal type and concentration, and pH significantly affected the absorption of plant heavy metals. The highest removal of heavy metals including Pb (45.9%) > Zn (36.1%) > Cr (32.8%) > Cd (27.5%) > Ni (25.9%) was related to the 20 mgL-1 and pH4 treatments by the order of root> stem> leaf> flower. The 5-10 mgL-1 concentration resulted in the highest removal efficiency resulted by stems (Ni, 44.12%), flowers (Zn, 44.00%), leaves (Cr, 44.14%) and roots (Cr, 44.36%). The highest bioconcentration (BCF) and translocation factors (TF) of 4.106 and 2 (Zn), 2.124 and 1.461 (Cd), 1.815 and 1.289 (Ni), 5.291 and 2.460 (Pb), and 2.811 and 1.885 (Cr) were resulted. Although with increasing heavy metal concentrations, the plant absorbed higher heavy metals, its removal efficiency decreased as it was the highest at the heavy metal concentration of 5-10 mgL-1. According to plant removal efficiency and the BCF and TF factors, it is possible to efficiently bioremediate water contaminated with heavy metals using C. longus.