Biodiversity in metal-polluted soils

Description

The research was carried out in the abandoned Libiola sulphide mine (NW Italy). This site presents serious environmental problems due to active Acid Mine Drainage processes, which determine acidification and heavy metals pollution of soils and waters. In this area most of the soil related to waste-rocks deposits exceeds commercial and industrial limits for heavy metals elements, such as Cr, Cu, and Ni.We evaluated the plant and fungal diversity in these contaminated soils in order to select tolerant and hyperaccumulating plants and fungal strains.The study area is characterised by different successional plant communities ranging from herbaceous to arboreal stages; the latter is represented by few Pinus pinaster Aiton. A screening test with dimethylglyoxime (DMG) was carried out on 65 plant taxa to highlight possible Ni accumulation in plant tissue obtaining a positive response in Thlaspi caerulescens J. & C. Presl, well-known metal hyperaccumulator and in Alyssoides utriculata (L.) Medik.Soil samples belonging to A. utriculata rhizosphere and other soils were examined to determine microfungal flora. The majority of isolated colonies belonged to the genus Penicillium, a common feature for copper contaminated soils, while occurrence of other genera, including Aspergillus, Clonostachys, Trichoderma, and Botrytis was significantly lower.DMG-positive plants, macrofungi, and their respective soils were analysed for heavy metals content revealing Cu > 1000 mg kg-1 in Thelephora terrestris Ehrh., and Ag > 50000 g kg-1 in Scleroderma polyrhizum (J.F. Gmel.) Pers. The results suggest the use of these plants and fungi to develop experimental protocols of bioremediation and habitat restoration.

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