EN
The paper analysed Cd, Cr, Cu, Pb, Ni and Zn concentration in bottom sediments of fourteen retention reservoirs located in the Oborniki and Taczanów forest districts (western Poland). The sediments were collected in March and April 2018 from a surface layer with a thickness of 5 cm. Heavy metal determination was performed using inductively coupled plasma with mass detection (ICP−QQQ) method. The aim of the work was to analyse the concentrations of heavy metals in bottom sediments of small forest retention reservoirs with respect to their pollution and toxic impact on the aquatic environment. In addition, the sources of heavy metals and factors influencing their accumulation in bottom sediments were assessed. The contamination of bottom sediments with heavy metals and their toxic effects on aquatic environment were determined using the index of geoaccumulation (Igeo), contamination factor (CF), pollutant load index (PLI) and toxic risk index (TRI). The cluster analysis and principal component analysis were used to divide the reservoirs into groups with a similar contamination of bottom sediments and to identify heavy metal sources. The heavy metals concentrations in reservoirs bottom sediments can be put in ascending order Cd.