In addition, both species are annual and fast-growing herbs, features
considered to be optimal for phytoremediation (Blaylock et al., 1997).
Other species from genera Tagetes and Bidens were reported for
phytoextraction of heavy metals from soils, but T. minuta and B. pilosa
have never been reported for this purpose. Most of the other studied
species also showed higher concentrations than plants growing on uncontaminated
soils, but with relatively low differences, indicating that
lead was transferred to plant tissues but not accumulated at concentrations
to be of interest for phytoremediation.