Ecological risk assessment of metals and metalloid in bottom sediments of water reservoir located in the key anthropogenic “hot spot” area (Poland)

Abstract

Study was aimed to assess the potential ecological risk of nine metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) and one metalloid (As) in bottom sediments of the Dzierżno Duże Reservoir located in the key anthropogenic “hot spot” area—Upper Silesian Industrial Region (Poland). Sediments were collected in seven sampling sites, along the main axis of a reservoir. Statistical analysis revealed a significant correlation (p < 0.05) between the potentially toxic elements, which indicated that they plausibly originate from the same source of contamination or have a similar accumulation behavior. Several indices were used to assess ecological risk associated with examined elements, i.e., Enrichment Factor, Geoaccumulation Index, Contamination Factor, Potential Ecological Risk Factor, Probable Effect Concentration, Threshold Effect Concentration, Degree of Contamination and Risk Index. The values of analyzed indices indicate that sediments are highly to extremely highly contaminated, especially by Cd, Pb, Zn, and As, which simultaneously pose the highest ecological risk. The results of Cluster Analysis (CA) and Principal Component Analysis (PCA) indicate that Cd, Cr, Fe, Ni, Pb, Zn, and As in the bottom sediments are most likely of anthropogenic origin, while Mn rather from natural sources. The obtained results confirm the usefulness of different indices in assessing the ecological condition of water bodies and prove that the problem of toxic elements contamination in bottom sediments of the Dzierżno Duże Reservoir poses a serious environmental threat.