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Phytoremediation of contaminated sediments: evaluation of agronomic properties and risk assessment

Bianchi, Veronica, Masciandaro, Graziana, Ceccanti, Brunello, Peruzzi, Eleonora, Iannelli, Renato
Chemistry in ecology 2011 v.27 no.sup1 pp. 1-11
Eisenia fetida, Paspalum vaginatum, Trifolium alexandrinum, breathing, copper, earthworms, grasses, heavy metals, humans, indicator species, land management, legumes, marine sediments, microbiology, phytoremediation, risk, risk assessment, shoots, soil, texture, vapors, zinc, Italy
This study evaluates the possibility of reusing marine sediments in land management. The sediments, dredged from Livorno port (Italy), had previously been phytotreated, using a salt-tolerant plant cover and earthworms, with the aim of reducing the salt level and improving the texture and microbiology. In this study, sediments were investigated in order to: (1) test their capability to be used as a revitalised soil-like substrate (techno-soil), and (2) assess the human exposure risks associated with sediment management. Results obtained after 6 months of experiments performed with biological indicators composed of an association of graminae grass (Paspalum vaginatum), legumes (Trifolium alexandrinum) and earthworms (Eisenia foetida), showed that the substrate behaves like a natural soil capable of supporting biological life (total N=0.2%; total P=0.7%; EC=1.5 mS·cm ⁻¹; β−glucosidase=20 μ g PNP·g *h ⁻¹). It was also found that plants accumulate small amounts of heavy metals in shoot tissues (120 mg Zn·kg⁻¹; 25 mg Cu·kg⁻¹). In detail, risk analysis was performed considering: (1) sediment storage in a sealed disposal basin inside the Livorno port area, and (2) off-site phyto-remediation. The maximum hazard index was found for workers inside the port area, with values of 1.7 and 25 for dermal contact and vapour inhalation risks, respectively.