About 5 years ago, we did a pilot phytoremediation
project in Boston. In one sense the pilot was very successful. Lead
levels were reduced 50% in one growing season and then 50% again the next.
However, when we costed out the effort, straight soil removal would have been
much more costly and definitely take a lot less time. This is because
there is a cost associated with raising the mustard and then with disposal of
the lead-laden plant material. We have had much better results with
designing the garden/park as a remediation strategy because generally the higher
lead levels are not uniform on the site.
Betsy Johnson, Boston Natural Areas Network,