Fractionation and Speciation of As, Cd and Zn in Aboveground Biomass of Alpine Pennycress (Thlaspi caerulescens J. & C. Presl)

Abstract

Fractionation and speciation of selected hazardous elements (As, Cd, Zn) in alpine pennycress (Thlaspi caerulescens J. & C. Presl) growing in extremely contami­nated soil were investigated using coupled analytical techniques. A semipreparative RP-HPLC followed by determination of the elements in chromatographic fractions by inductively coupled plasma mass spectrometry (ICP MS) was applied to identification of interactions of the elements with plant pigments. The elements in plant extracts were detected by SEC coupled on-line with ICP-MS. For determination of As species HPLC – ICP MS was used. Total contents of the elements in T. caerulescens biomass confirmed hyperaccumulation of Cd and Zn, their contents reaching up to 719 and 10 570 μg g^–1 of dry matter, respectively. A predominant part of extractable Zn (ca 99 %) and Cd (ca 98 %) was present in ionic forms and labile complexes. A possible phytochelating synthesis was not confirmed as the dominant mechanism of plant tolerance to enhanced Cd and Zn concentrations. Inorganic As species were also identified. The results indicate the presence of stable complexes but require further research.