Comparison of cadmium, nickel, lead and thallium translocation in Malva verticillata L. grown in hydroponic system

A wide range of agricultural lands has been contaminated with various heavy metals, severely impacting food security and human health.In this study, we investigated the uptake and translocations of cadmium (Cd), nickel (Ni), lead (Pb), and thallium (Tl), in Malva verticillata L, using different parameters, including bio-concentration factors in shoot and root (BCF-ST and BCF-RT) and the translocation index (TLI), under hydroponic conditions with 0, 5, 15, 30, and 50 mg L -1 of each target metal applied.Metal concentrations ranged from 21.1 mg kg -1 for Pb to 971.1 mg kg -1 for Ni in the shoots, and from 155.1 mg kg -1 for Ni to 2489.7 mg kg -1 for Pb in the roots.Metal accumulation followed the order Ni > Tl > Cd > Pb in the shoots and Pb > Tl > Cd > Ni in the roots.BCF-ST values for Cd, Pb, and Tl declined with increasing metal concentrations, whereas those for Ni tended to increase.Conversely, BCF-RT values for Cd, Ni, and Pb increased, while those for Tl decreased.Cd, Ni, and Pb concentrations in the shoots were positively correlated with their respective root concentrations, and BCF-ST values for these metals were also positively correlated with their corresponding TLI values (p < 0.1 to p < 0.05).Significant positive or negative correlations (p < 0.05 to p < 0.01) were observed among the measured parameters for Tl.Furthermore, BCF-ST values between Pb and Tl, as well as TLI values between Cd and Pb, were positively correlated, both with significance at p < 0.1.Thus, the movement and accumulation of heavy metals in Malva verticillata L. appear to be governed by metal-specific interactions within this plant species.