Soil microfungi in an area polluted by heavy metals

The microfungal species composition was studied in coniferous forest soils surrounding a brass mill at Gusum in southeast Sweden. Both the Cu and Zn concentrations were ca. 20 000 μg/g dry soil close to the mill. Pb concentration was ca. 1000 μg/g dry soil and the pH about 2 units above the normal of 3.5–4. The microfungal species composition (determined by the dilution plate technique) was strongly affected by the heavy-metal contamination. Close to the mill there was a decrease in isolation frequency of fungi common in coniferous forest soils, e.g., Penicillium spinulosum, P. montanense, P. brevicompactum, Oidiodendron cf. tenuissimum, O. cf. echinulatum, and O. maius. Other less common or rare fungi increased, e.g., Paecilomyces farinosus, Geomyces pannorum, Chalara constricta, C. longipes, and sterile forms. Fungi of the genus Mortierella seemed affected little by the heavy-metal contamination. Multivariate statistical analyses showed that the heavy-metal pollution was the dominating influence along the metal gradient and that soil moisture and loss on ignition accounted for little of the variation in the fungal data.