Accumulation of metals by fungi has been known for a few decades and a number of works describing metal content in fruit bodies collected in different areas have been published (Mejstrik and Lepšová 1993). A key role in metal accumulation by fungi has been attached to cell wall polysaccharides, cysteine-rich proteins and pigments like melanin (Siegel et al. 1990). Some higher fungi are known to have the ability to accumulate toxic elements such As, Cd or Pb from the environment (Stijve et al. 1990, Vetter 1994, Tyler 1982. Heavy metal content in many terrestrial fungi correlates with metal concentration in the soil in which they grow (Gast et al. 1988). In the case of edible fungi, toxic metals may be incorporated into food chains.Fungal species growing on wood contain, in general, lower concentrations of heavy metals than fimgi growing on soil (Mutsch et al. 1979), probably due to limited contact of mycelia with the soil. Nevertheless, wood-inhabiting fungi growing in polluted areas may contain higher amounts of toxic metals than fungi growing in unpolluted areas, as we demonstrated for beryllium (Gabriel et al. 1995) previously. Wood-decaying fungi take up heavy metals by deposition of particles from the atmosphere and absorption from the substrate. Literature data indicate that heavy metal content decreases from soil through roots to stems (Salt et al. 1995). Earlier experiments (Brunnett and Zadrazil 1981, Gabriel et al. 1996a) confirmed translocation of heavy metals from substrate into the fruiting bodies of lignocellulose decomposing fungi. Atmospheric dry or wet depositions represent another considerable source of metals in plants and plant related parasites or saprophytes (Hovmand et al. 1983).The purpose of this work was to examine heavy metal content (Al, Cd, Cu, Pb and Zn) in six wood-decaying fungal species collected in polluted and unpolluted areas in the Czech Republic.

The ability of fungi to accumulate metals is a known phenomenon that is studied from both the industrial and ecological point of views. The biosorption and removal of various cations could be useful in recovery of precious or strategic metals (e.g. Nakajima and Sakaguchi 1993) as well as in the removal of toxic heavy metals from contaminated water (Siegel et al. 1990). The most frequently used group of organisms are filamentous fungi (e.g. Siegel et al. 1990, Pümpel andSchinner 1993) which are widely used in fermentation industries to produce varied metabolites. The application of mycelial wastes as adsorbents or ion-exchangers for the removal of heavy metals represents a possibility for further utilization of these biotechnological by-products (Voleský 1994). So far, little attention has been paid to interactions of heavy metals with higher fungi. Most of the work deals with metal translocation and uptake from various substrates or with the heavy metal content in fruiting bodies collected in different areas. In several cases this content seems to reflect the concentrations of atmospheric heavy metal.Most wood-rotting basidiomycetes can be found in high yields and are easily cultivated allowing various model experiments such as the investigation of metal translocation and uptake or the study of heavy metal induced changes in fungal morphology and biochemistry. The effect of Cd, Zn and some other metals on the growth of some ectomycorrhizal fungi (Darlington and Rauser 1988, Colpaert and Van Assche 1992) and hyphomycetes (Rózycki 1993, Failla andNiehaus 1986) have been investigated. Recently, element distribution in mycelium of Pisolithus arrhizus (PERS.) RAUSCH. treated with Cd dust has been described (Turnau et al. 1994). Some alterations in mycelial morphology were reported by Lilly et al. (1992) who found the loss of hyphae orientation and decrease of clamp connections in mycelium of wood-rotting basidiomycete Schizophyllum commune FR.:FR. treated with milimolar concentrations of Cd. When submerged mycelial pellets of this fungus where cultivated in the presence of lead, color change was documented (Gabriel et al. 1994).

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Conventional electrothermal atomic absorption spectrometric (ETAAS) equipment was extensively modified to enable automated in situ electrodeposition. The original autosampler injection Teflon capillary was replaced by a composite Pt/Teflon capillary which served as an anode in the electrodeposition circuit. Incorporation of a peristaltic pump and of a three-way solenoid under computer control into the sample dispenser circuit provided all necessary steps for automated electrodeposition-ETAAS determination. The automated sequence controlled addition of Pd modifier and of the analyte, electrolysis, withdrawal of spent electrolyte, rinsing, drying and atomization. Performance of the system was evaluated by analyzing Pb in 3% m/v NaCl. Optimization using factorial design yielded 3sigma detection limit of 20 pg Pb and reproducibility of 1.0-1.4% (for constant current electrodeposition), these values being superior to the results of conventional ETAAS of Pb in 0.5% m/v NaCl. Sensitivity of Pb determination is not affected by NaCl, NaOH, NaNO3 and NH4H2PO4, up to 4.6% m/v, demonstrating efficient matrix removal in the electrodeposition step.

Speciation and simultaneous preconcentration of Cr(III) and Cr(VI) is based on the sorption of the reaction product of Cr(III) with Chromazurol S in weakly acidic solution and the sorption of the reaction product of Cr(VI) with sodium diethylcarbamate in strongly acidic solution. Reversed C18 phase was used for sorption of both the products. Both the complexes were eluted from columns directly into an AAS nebulizer using methanol. All the processes were automated. This method can be used for initial concentrations of Cr(III) and Cr(VI) below 1 ppm. The detection limits were 0.2 μg l-1 for Cr(III) and 2.4 μg l-1 for Cr(VI). This method was tested for analysis of practical samples (drinking and surface waters and soil extracts).