Application of the Stripping Voltammetry Method for the Determination of Copper and Lead Hyperaccumulation Potential in Lunaria annua L.

Abstract

Various species of the Brassicaceae family are known to hyperaccumulate metals. Lunaria annua L., a plant from the Brassicaceae family, is an oilseed crop known for its pharmaceutical and nutraceutical applications. In this work, Lunaria annua L. was investigated for its accumulation potential in copper and lead-contaminated soil. Concentrations of copper and lead were measured before planting (in seeds and soils) and after the plant was harvested (in soils and plant). Two types of soils were used: a soil sample collected from the Botanical Garden of the Faculty of Science, University of Split (soil 1, S1) and a commercially available organic mineral substrate (soil 2, S2). Measured pH values showed that the S1 (pH = 8.58) was moderately alkaline soil. On the other hand, the purchased organic soil, S2 (pH = 6.35), was poorly acidic to neutral. For the determination of copper (Cu) and lead (Pb), square wave anodic stripping voltammetry (SWASV), using a glassy carbon electrode modified with mercury film, was applied. The concentrations of Pb and Cu were determined and calculated in the sample using the standard addition method. Obtained results have shown that Lunaria annua L. is a lead hyperaccumulator (4116.2 mg/kg in S1 and 3314.7 mg/kg in S2) and a potential copper accumulator (624.2 mg/kg in S1 and 498.9 mg/kg in S2). Likewise, the results have shown that the higher the pH is, the lower the possibility that metal accumulation exists.