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In situ and ex situ bioremediation and rhizoremediation of PAH and PCB polluted sites Laura Bardi laura.bardi@entecra.it, Mario Marzona, Roberto Ricci, Raffaella Fabbian C.R.A. Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Istituto Sperimentale per la Nutrizione delle Piante, Torino Riassunto La bonifica di suoli ed acque per uso agrario costituisce una problematica di rilevante importanza ai fini della sicurezza e salubrità dei prodotti alimentari; difatti alcuni xenobioti organici, come alcuni idrocarburi poliaromatici (PAH) ed i policlorobifenili (PCB), sono recalcitranti alla biodegradazione e passano nella catena alimentare. La degradazione può essere migliorata ed accelerata con opportuni interventi tecnologici. La bonifica delle acque è drasticamente migliorata ex situ utilizzando consorzi microbici selezionati, aumentando la biodisponibilità degli xenobioti mediante l’uso di βciclodestrina e controllando la temperatura. La bonifica dei suoli può essere ottenuta in situ mediante rhizoremediation, associando una coltivazione non-food alla biodegradazione ad opera di microrganismi rizosferici. Summary The use of polluted lands for food crops is a main problem for human safety because several organic xenobiotics, such as polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) are recalcitrant and pass through the soil and water into the food chain. Biodegradation can be improved and accelerated by technological processes. Water bioremediation is strongly improved with ex situ processes by selected microbial consortia, by increasing bioavailability with β-cyclodestrin and by temperature control. Soil bioremediation can be reached in situ by rhizoremediation, that associates a non-food crop to degradative activity of rhizospheric microorganisms. 1. Introduction Organic xenobiotics are widespread in soils and water and through the food chain they become a main health risk for humans. In fact, some organic xenobiotics are rapidly degraded by microorganisms in soil, but the most recalcitrant among them remain for a longtime in soil, pass into the plant roots and accumulate in different vegetable tissues. The polluted agricultural soils should then be devoted to other uses for long periods, but this can be a social significant problem. The cultivation of industrial crops, such as biomassproducing plants as a source of renewable energy, as an alternative to food-producing crops, can become an important tool to contemporarily reach an efficient bioremediation process and get income. Most organic xenobiotics can be degraded by microorganisms that use them as energy and carbon sources. Several studies have been carried out to accelerate and improve their bioremediation by low-impact technologies, mainly aimed at maintaining the natural characteristics of soil, by stimulating the activity of autoctonous microorganisms; also the rhizoremediation, where the plant roots aid and increase the degradation activity of soil microorganisms, can improve biodegradation.

16 bioremediation pah and pcb ecomondo 2007  
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