Impact of vegetation on the mobility and bioavailability of trace elementsin a dredged sediment deposit: a greenhouse study

摘要

In France, high quantities of heavy metal contaminated sediments are dredged each year and deposited on soils without any protection. Despite their high pollutant content, a vegetal cover generally appears spontaneously on these deposits. However, the growth of plants on the sediments can have an impact on the heavy metal behaviour. In order to evaluate this impact, a greenhouse experimentation was designed to measure the heavy metal (zinc, cadmium, lead, copper) mobilisation during the growth of different vegetal species, and their absorption by vegetation. The results indicate that high concentrations of heavy metals are absorbed by the plants. Moreover, the establishment of a vegetal cover (maize, rape and rye grass) on dredged sediments is able to quantitatively modify the physico-chemical parameters of the sediments, and to increase the mobility of the heavy metals inside.