Ocena zanieczyszczenia osadów antropogenicznych zbiorników wodnych w centralnej części Wyżyny Katowickiej

The paper deals with sediments of anthropogenic reservoirs from the central part of the Katowice Upland. Over most of the area, the original relief was considerably altered due to many-years’ mining of hard coal, historical mining and processing of zinc-lead ores, smelting of iron and non-ferrous metals, and chemical and machinery industries. The changes in land surface give rise to mining collapse areas transformed to water reservoirs. Sediment samples (103 samples in total) were collected form artificial lakes, ponds and settling ponds. Samples were air-dried, sieved through a 0.2-mm nylon sieve and digested in aqua regia. Contents ofAg, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P Pb, S, Sn, Sr, Ti, Vand Zn in the samples were determined by the ICP-OES method. Mercury content was measured using the CV-AAS method. To assess the extent of sediment contamination the Index of Geoaccumulation (Igeo) and the ecotoxicological (Threshold Effect Concentration and Probable Effect Concentration) criterion were used. The sediments show very different chemical compositions. The content of trace elements varies from values lower than the regional geochemical background of the Silesian-Cracow region to extremely high concentrations. Distribution of many toxic chemical elements is characterized by high spatial variability and a strong dependence on the location of pollution sources. About 60% of analysed samples were heavily contaminated due to the very high concentration of cadmium (up to 905.9 mg/kg), lead (up to 25,081 mg/kg) and zinc (up to 45,361 mg/kg) as well as arsenic (up to 2,220 mg/kg), chromium (up to 901 mg/kg) and mercury (up to 11.80 mg/kg). Due to the concentration of metals (TEC and PEC values) almost 80% of the sediments can be harmful to aquatic organisms, as well as to wild animals that consume them. The main cause of harm is the very high concentrations of cadmium, lead and zinc, less of silver, arsenic, chromium, copper and nickel.