Ecological impact and remediation of contaminated sites around lead smelters in Poland

Abstract

The contamination with heavy metals of soil and plants grown in the vicinity of a lead smelter has been assessed. Lead, zinc and cadmium content in soils and plants (cereals and vegetables) grown on cultivated land, in allotment and home gardens situated up to 5 km from the smelter (28 sampling sites) has been analyzed. The analysis of heavy metals content has been done both in cereal grain and in straw. In vegetables, the edible subsurface parts and leaves (in case of celery and parsley) have been analyzed (AAS method). Concentrations of heavy metals were determined after extraction with 10% nitric acid for soil samples und potassium sulfate solution in concentrated nitric acid for plant material mineralization. Zinc concentrations in soils were in the range of 180.8 to 10643.9 mg/kg of dry matter; lead concentrations — 128.9 to 1996.4 mg/kg; and cadmium — 3.30 to 102.20 mg/kg. The highest concentrations of metals in soil were observed 4 km from the smelter in the north-east direction. Metals concentrations in soils have been compared with admissible values in Poland. Maximum exceedances of these values were: for zinc — up to 36 times, for lead — up to 20 times and for cadmium — up to 34 times. Concentrations of metals in cereal grain were: 30.3–111.7 mg/kg of dry matter for zinc; 0.03-1.6 mg/kg for lead; and 0.10-2.16 mg/kg for cadmium. In vegetables the highest concentrations of metals have been found in celery and parsley leaves. They were: 136.3–1007.9 mg/kg of dry matter for zinc; 7.3–46.2 mg/kg for lead; and 1.30-17.64 mg/kg for cadmium. The concentrations of metals in the subsurface parts of analyzed vegetables were 47.0–1321.1 mg/ kg of dry matter for zinc; 1.8–10.7 mg/kg for lead; and 0.87-8.84 mg/kg for cadmium. The largest exceedances have been noted for cadmium (from several to 80 times). In order to assess the location of edible plants cultivations, land classification method was used. The method was developed at the Institute of Environmental Protection and it classifies the land used for agricultural purposes according to pollutant concentrations in the environment. Category A allows for production without constraints; category B points out the necessity of introducing certain restrictions in species of cultivated plants and using specific agricultural treatment; the land classified as category C should not be used for edible plants cultivation. The majority of the analyzed areas discussed in this paper have been classified as belonging to category C; a few belong to category B.