Impact of nanoparticles on the phytoremediation potential of Coleus amboinicus Lour.

Contamination of soil by toxic heavy metals is a serious environmental issue which requires an effective remediation method. Phytoremediation, a cost-effective plant-based technology, can be effectively used to clean up the soil, air and water that is contaminated. The present study was conducted to investigate the cadmium (Cd), nickel (Ni) and lead (Pb) phytoremediation potential of Coleus amboinicus, a terrestrial plant that has been reported to accumulate heavy metals efficiently. In addition, the effect of magnesium oxide (MgO) and zinc oxide (ZnO) nanoparticles on the accumulation of Cd, Ni and Pb in C. amboinicus was evaluated. The results revealed that C. amboinicus could effectively accumulate Cd, Ni and Pb proving it to be a good option for the remediation of soils contaminated with these heavy metals. The application of MgO and ZnO nanoparticles could enhance the accumulation of Cd in the roots (4% and 94% respectively) and shoots (137% and 276% respectively) of C. amboinicus compared to the Cd only treated plant. However, root and shoot accumulation of Ni and Pb was reduced by the application of MgO and ZnO nanoparticles. It was also found that Cd, Ni and Pb and MgO and ZnO nanoparticles reduced all the growth parameters, root volume and tolerance index compared to the control C. amboinicus plants. Further research is necessary to clarify the underlying mechanisms and to improve this strategy for phytoremediation.