Does Iron Plaque Improve the Uptake and Translocation of Lead by Broad-leaf Cattail in Lead-contaminated Soils

The inhibited or enhanced uptake of heavy metals by iron plaque has been observed. The relationship between amounts of adsorption and accumulation of heavy metals and iron plaque on roots of wetland plant is still unclear. This study examined the effects of iron plaque on lead (Pb) absorption and translocation between underground and above-ground parts of a wetland plant species. Broad-leaf cattail (Typha latifolia L.) was grown in soil for four weeks under waterlogged conditions in a greenhouse. The soils were treated by Pb as lead nitrate at four levels (0, 100, 500 and 1000 mg Pb·kg

−1

) and waterlogged for two weeks. The results showed that the amount of iron plaque in the treatment with addition of 500 mg Fe·kg

−1

was general higher than that of the treatment with addition of 100 mg Fe·kg

−1

, Lead concentrations in both shoots and roots treated by 500 mg Fe·kg

−1

was more than that of the treatment with 100 mg Fe·kg

−1

. When the ratio of added Fe and Pb was 1, the accumulation of Pb in plants was higher than that of other treatments at the same Pd level. Appropriate amount of iron supplied will benefit lead accumulation in plant, which help the removal or stabilization of lead in constructed wetland.