Pb. Zinc uptake was high, and was accumulated in a linear fashion in root tissue across the
sediment Zn concentration range applied. Zinc translocation to leaf tissue exhibited a dose
dependant relationship with both root and sediment Zn levels. Emergence decreased with
increasing sediment Zn concentrations, with 1000 mg/g sediment Zn showing 100% mortality.
Significant reductions in seedling height, leaf number, area, biomass and root growth inhibition
were found at concentrations of 500 mg/g sediment Zn. The LC50 for emergence and EC50
for biomass was 580 and 392 mg/g Zn respectively. Lead and Zn in combination resulted in an
increased accumulation of both metals in leaf tissue and increased toxicity than individual
metals alone, and is the first noted occurrence of a Pb and Zn additive response in angiosperms.
Possible mechanisms of accumulation and toxicity are discussed. # 2002 Elsevier
Science Ltd. All rights reserved.