TRACE-METAL CONTAMINATION OF SOILS AND CROP PLANTS BY THE MINING AND SMELTING INDUSTRY IN UPPER SILESIA, SOUTH POLAND

Mines, smelters, power plants and other industries are sources of metal emissions to the Upper Silesia environment. The ranges of concentrations of the primary metallic contaminants in the arable soils of the region are broad (in mg/kg, dry wt.): Cd 0.1-143.0; Pb 4-8,200; Zn 5-13,250. The geometric means of concentrations of these elements in the soils are as follows (in mg/kg, dry wt.): Cd 3.2; Pb 102.3; and Zn 270.2. Only 10% of the arable land has natural concentrations of the trace metals, that is concentrations up to 0.6, 25, 100 mg/kg for Cd, Pb, and Zn, respectively, and about 60% of the soils have concentrations of Cd and Zn higher than critical values (Cd 2 mg/kg, Zn 200 mg/kg). Concentrations of Pb exceeded the critical level (100 mg/kg) in about 45% of the studied soils. Cereals and potatoes produced in the Tarnowskie Gory region, the most contaminated area of Upper Silesia, are contaminated with Cd, Pb and Zn. About 95% of the cereal and all potato samples had Cd concentrations higher than limit level in food (0.1 mg/kg). However, only 25% and 20% of cereal grain and potato tubers (peeled), respectively exceeded the metal limit in forage (0.5 mg/kg). Contamination of the crops with Pb and Zn is of smaller importance because concentrations of these metals in the cereals and potatoes are usually within ranges tolerated by animals.