UPTAKE OF CADMIUM, LEAD, NICKEL AND ZINC FROM SOIL AND WATER SOLUTIONS BY THE NICKEL HYPERACCUMULATOR BERKHEYA CODDII

Berkheya coddii Roessler (Asteraceae), an endemic herbaceous and perennial nickel-hyperaccumulating plant growing on Ni-enriched ultramafic soils in South Africa, is perceived as a promising species for phytoremediation and phytomining due to its large biomass production and high Ni content. Total concentrations of a number of elements in mature leaves, soil and related bedrock were obtained. The average Ni concentration in leaves was 18,000 µgg -1 dry mass, whereas in soil and bedrock the total amount of Ni was 1,300 µgg -1 and 1,500 µgg -1 , respectively. Exceptionally high average Ni concentrations (55,000 ± 15,000 µgg -1 , n = 6) were found in B. coddii leaves from Songimvelo Game Reserve, including the highest-ever reported concentration of Ni in leaves (76,100 µg  g -1 - maximum value in a single sample). Young plants grown in pots with ultramafic soil accumulated small quantities of Cd, Pb or Zn, but the concentrations of these elements increased after the addition of metal solutions to the soil. Excised shoots immersed in concentrated solutions of Cd, Ni, Pb or Zn accumulated large amounts of these metals in the leaves.