The Niepołomice Forest is a large forestcomplex (110 km2) situated in southern Poland 10 to 30 kmto the east of the urban industrial Kraków agglomeration andsteelworks, which was built up on the outskirts of the city in1950. Due to prevailing westerly winds, the forest is affectedby pollutants emitted by both the steelworks and the city. Thelevel of heavy metal contamination in the Niepołomice Forestwas described using a sensitive bioindicator – the moss Pleurozium schreberi. Mean concentrations of metals in mosscollected in the Niepołomice Forest were Cd – 0.71, Cr – 2.4,Cu – 8.6, Fe – 673, Pb – 12.7, and Zn – 61 mg/kg.Concentrations of heavy metals in moss in the NiepołomiceForest decreased in time. As compared with the relatively cleanarea in north-eastern Poland (Puszcza Białowieska), the concentration of Fe was 2–9 fold and Pb 4–6 fold higher in theNiepołomice Forest in 1975, while in 1998 4 fold and 2 fold,respectively. In both 1975 and 1998 the most polluted by heavymetals was the western part of the Niepołomice Forest (closestto the pollution sources) and the area along the roads insidethe forest complex.