Un Sistema vegetato per la biorimediation di un suolo inquinato da metalli pesanti e idrocarburi: "Il caso di Madonna dell'Acqua in Toscana"

This work is a part of a project carried out by CNR-ISE – Pisa, in collaboration with S. Giuliano Terme (Pisa) Municipality. Aim of the project was to test and apply bioremediation techniques to a heavy metal and hydrocarbon contaminated site (Madonna dell’Acqua, Tuscany). The bioremediation system studied included the use of plants, earthworms and organic matter. The final objectives were dual: decontamination and biophysical regeneration of soil in order to recover its ecological functionality. The experimental design were: soil (T); soil + manure (M); soil + manure + earthworms (ML). Three different species were used for each treatment: two trees (Populus nigra, var.italica and Paulownia tomentosa) and a bush (Cytisus scoparius). During a year of experimentation, total petroleum hydrocarbons (TPH) and heavy metals (Pb, Zn, Ni, Cu, Cr, Cd), were determined along with parameters related to soil metabolic processes. All plant species were able to grow in polluted soil activating C, N, P element cycles and promoting heavy metals solubilisation and plant uptake. The experimentation demonstrated the effectiveness of the plant-microorganisms-earthworms combination for the bioremediation of Madonna dell’Acqua polluted site. Heavy metal and hydrocarbon content was reduced by 30% and the biochemical functionality of the soil was improved.