Comparative Study of Cd, Pb, and Ni removal potential by salvinia natans (L.) All. and Lemna minor L.: Interactions with Growth Parameters

Abstract

The aim of this study was to identify the biological responses and phytoremediation capability of two aquatic macrophytes: Salvinia natans and Lemna minor. Lemna and Salvinia species were exposed to different concentrations of Pb, Cd, and Ni for 7 days. The bioconcentration factors (BCF) of heavy metals from water to these two aquatic macrophytes were estimated and the removal potential of heavy metals was assessed. After 7 days, some biological parameters were measured, including metal accumulations in leaves, photosynthetic pigmentations, Lipid peroxidation activity, and growth rates. For S. natans, the highest Pb accumulation was found in 50 mg l-1 concentration. The amount of chlorophyll a (chl a) in L. minor was reduced to a minimum value of 0.120 mg g-1 with the 8 mg l-1 Cd concentration. The Relative Growth Rate (RGR) values of both plants were negatively associated with metal treatment. The levels of Malondialdehyde (MDA) in S. natans increased to a maximum value of 7.174 nmol/g with 50 mg l-1 at Pb concentration-dependent and time-depended action. S. natans was a more effective Pb and Ni accumulator than L. minor, but L. minor was a more effective Cd accumulator than S. natans. Our findings might be useful for the phytoremediation of water polluted with heavy metals.