The effect of heavy metals on soil microorganisms may be obscured by other environmental factors, for instance, soil pH is known to affect mobility and thus bioavailability of heavy metals (McBride et al., 1997). Therefore in our study, we tried to limit vari- ability of factors other than heavy metal pollution by sampling soils developed from similar parent materials (sands), with the same water regime (no ground water present in the soil profile) and covered by similar vegetation (Scots pine forest, Vaccinio Myr- tilli – Pinetum). Nevertheless, the soils of the two sampled regions differed from each other in pH, which was on average one unit higher in the soils of the Olkusz region. We presume that higher soil pH in the Olkusz region compared with that in the Legnica region was due to differences in geology of the two regions. In both regions the studied Podzol soils developed from Quaternary sands of fluvoglacial deposition.