The Effects of Copper and Lead on Growth and Zinc Accumulation of Thlaspi Caerulescens J. and C. Presl: Implications for Phytoremediation of Contaminated Soils

Abstract

Thlaspi caerulescens J. and C. Presl is a Zn-hyperaccumulatingplant which has aroused considerable interest with respect to its possible use for phytoremediation of Zn-contaminated soils. In this work, a British population of T. caerulescens, from a soil which was found to have relatively high concentrations of water-extractable Cu (0.22 mg L-1), Pb (0.99 mg L-1) and Zn (6.49 mg L-1), was studied. Its ability to grow and accumulate Zn from hydroponic nutrient solution in the presence of elevated concentrations of Cu and/or Pb was investigated. The chosen concentrations of Cu, Pb and Zn were based on reported water-soluble concentrations of these heavy metals in contaminated soils. When supplied with 32.7 mg L-1 Zn, plants accumulated 19 780 mg kg-1 Zn in their shoot dry matter. This concentration declined by 9.3, 87 and 84% respectively when 5.0 mg L-1 Pb, 1.0 mg L-1 Cu or 2.0 mg L-1 Cu were included in the nutrient solution. Despite the apparent adaptation of this population of T. caerulescens to a Zn/Pb/Cu-contaminated soil, these Cu treatments strongly inhibited growth, but the Pb treatment did not affect growth significantly.