Use of the native vascular flora for risk assessment and management of an industrial contaminated soil

potentially toxic elements (PTEs) to assess the relationship between spontaneous vegetation and pollution levels, the potential risks for biological communities and ecosystems, and the potential of native plant species for phytoremediation. PTE concentrations had negative effects on plant biodiversity, as determined through changes in the Shannon index, Pielou evenness index and species richness. Poaceae and Asteraceae were moderately affected by soil contamination, while PTE levels had a negative effect on the other species groups. Cadmium had the greatest effect on plant species diversity, followed by zinc and then lead. The ecological risk index showed a mean value of 4924, corresponding to a very high risk in most plants. Target PTEs for phytoremediation were Cd (3813 on average) followed by Pb (937 on average) contributing to the ecological risk index, respectively from 42 to 81% and from 11 to 24%, in spite of the much higher concentrations of Pb. The most frequent species were Holcus lanatus subsp. lanatus and Silene latifolia that showed good adaptability to contamination, growing in very high-risk areas. S. latifolia reported high concentrations of Tl both in shoot and in roots, at levels typical of hyperaccumulator species. High values of bioaccumulation (BACS, BACR) and translocation factors (TF) confirmed that this species may be considered a hyperaccumulator of Tl. Holcus lanatus and Silene latifolia proved the most suitable species respectively for Cd and Pb phytostabilization and can be used in association for soil cover during the summer when soil resuspension is generally more intense and for protecting groundwater from pollutant leaching.