Using trees to restore heavy metal values to within acceptable limits
This has the potential for low contamination scenarios only. It is unlikely if contaminant levels are moderate to high.
Metal uptake for some tree species is low when compared to the potential amounts of metals present in contaminated soils. However, not all of the pollutant has to be removed, as the ‘bioavailable’ part is the most important for minimising transfer of pollutants to crops or groundwater. This will be more effective for metals with greater lability, such as cadmium and zinc.
Removal of metals by short rotation coppice (SRC)
We have recently undertaken research examining the removal of metals by short rotation coppice (SRC) on a site which had been subjected to a heavy application of sewage sludge. Results indicated that the SRC was highly effective at removing zinc but less so for copper, nickel or lead.
This work was funded by Southern Water and the Forestry Commission.
Ongoing research
Further growth trials have recently been set up which will monitor metal removal by a broad range of tree species as part of the Bioindicators research.
