The activity of selected soil enzymes, and soil contamination with zinc, cadmium and lead in the vicinity of the zinc smelter "Miasteczko Slaskie"”

Abstract

Heavy metals are a serious source of soil pollution, especially in the vicinity of metal smelters. This study examines the effect of selected heavy metals on the activity of soil enzymes (acid phosphatase, dehydrogenase, β-glucosidase, urease and protease) in topsoil (0–30 cm) in the vicinity of the zinc smelter "Miasteczko Slaskie". Soil enzyme activity in the polluted site was compared with a non-polluted site in the outskirts of the Pazurek nature reserve (near Olkusz). Soil samples were collected in coniferous communities. The activity of soil enzymes were compared at distances of 0.5 km, 1 km and 1.5 km from the emitter. In the vicinity of the emitter (all distances) Cd, Pb and Zn levels in topsoil exceeded acceptable limits. Also, Pb content at a non-polluted site (Pazurek nature reserve) was higher than permissible levels. Zn (HNO3 extracted) were the highest in the topsoil samples collected at a distance of 1.5 km from the Miasteczko Slaskie plant, Cd (HNO3 and CaCl2 extracted) and Pb (CaCl2 extracted) contents were highest at the distance 1 km from the emitter. However, the pollution index in the superficial soil layer (0–10 cm) was similar at all three distances from the emmiter. The Zn, Cd and Pb bioavailable concentrations (CaCl2 extracted) ranged: 15–220, 0.1–7.2, 2.8–55.7 mg . kg–1 respectively. The greatest decreases were found for acid phosphatase, dehydrogenase and protease activity at the distance of 0.5 km from the emitter. Results show that soil enzymatic activity should accompany basic chemical analysis to track disorders and adverse effects in polluted soil.