A study was carried out on 20 water bodies of the same origin in southern Poland. The study objectives included the assessment of toxic metal contamination in the bottom sediments of the water bodies in comparison with the geochemical background and sediments found in the substrate (i.e., vicinity) of the water bodies (i.e., the formations present in the surroundings of the water body itself), thus demonstrating the scale of anthropogenic enrichment of bottom sediments with toxic metals and assessing the cumulative impact on water bodies. The following amounts of toxic metals were found in the bottom sediments of the water bodies examined: 181.7-35200.0 ppm for zinc, 33.3-1648.8 ppm for lead, 1.8-359 ppm for cadmium, 14.0-271.5 ppm for copper, 45.3-167.5 ppm for chromium, and 12-128.5 ppm for nickel. Ratios of the values measured to the geochemical background were as follows: 0.7-135.9 (Zn), 0.6-53.0

Land subsidence caused by mining activities is an example of human transformation of the natural environment and leads to changes in land use. The study covers an area of 958 ha in the Silesian Upland, southern Poland. Records from the period 1890–1990 document the presence of subsidence effects in 82.9% of the study area and the maximum displacement figure is more than 30 m which translates to an average rate of 0.3 m per year. It was found that subsidence basins serve as the new local erosion base and new sedimentation basins. They are filled with sediments whose level of pollution ranges from moderate to heavy and extremely heavy. Subsidence has caused a dramatic change in the local hydrology, including the quality and quantity of the water. The specifics involve: the emergence of new closed drainage catchments with a total area of 651.1 ha; an increase in the total watercourse length (from 0.9 to 5.7 km); an increase in the river network density (from 0.09 to 0.56 km km−2); a decrease in the number (from 81 to 48) and an increase in the area (from 23.8 to 58.4 ha) of lakes and ponds; an increase in the lake coverage ratio (from 2.5% to 6.1%) and in water pollution. Subsidence has limited the potential land uses, which led to a decrease in arable land from 619.0 to 122.5 ha that gave way to other land uses, including those equivalent to wasteland. Copyright © 2016 John Wiley & Sons, Ltd.

An assessment was carried out of the anthropogenic enrichment of the chemical composition of the bottom sediments of water bodies situated in an area with an urban and industrial character (63.7% of the total area). The endorheic catchments of the water bodies studied are lithologically uniform with sandy formations accounting for more than 90% of the surface area. On the basis of geoaccumulation index values, it was found that the bottom sediments of the water bodies studied were contaminated with the following elements: Cd, Zn, S, As, Pb, Sr, Co, Cr, Cu, Ba, Ni, V, Be, in degrees ranging from moderate to extreme, with lower contamination (or absence of contamination) with the same elements being found in the formations present in the vicinity and in the substrate of the basins of water bodies. It was found that one consequence of the fact that these water bodies are located in urban and industrial areas is that there is anthropogenic enrichment of the chemical composition of bottom sediments with certain basic components (organic matter, Mn, Ca and P compounds) and trace elements: Cd, Zn, Pb, Sb, As, Cu and Co, Br, Ni, S, Be, Cs, Sr, V, Cr, Sc, Ba, U, Ce, Eu and Th, with virtually no enrichment of sediments with the other basic and trace components analysed (La, Rb, K2O, Nd, Sm, Na2O, Hf, SiO2, Zr).

Purpose Cadmium (Cd) is considered a toxic element and its concentrations are relevant to human health and the environment. Therefore, the purpose of the study was to determine the extent to which the bottom sediments of water bodies (artificial lakes and ponds) in the Silesian Upland in southern Poland are contaminated with Cd; an attempt was also made to determine the factors that condition spatial differences in the concentration of this element between individual water bodies in the region. Materials and methods Measurements of the Cd content in bottom sediments were carried out in 35 water bodies in southern Poland in 2011 and 2012. Depending on the surface area and morphometric characteristics, from two to nine samples representative in terms of sediment thickness were collected in each water body. Cadmium concentrations were determined for 92 0.25 g aliquots using the TD-ICP method. Results and discussion Cadmium content in all samples (0.7-580.0 mg kg ) and, with a few exceptions, was also higher than the preindustrial concentration (1.0 mg kg ) as the baseline for the geoaccumulation index (I geo ), the sediments examined can be classified as extremely and heavily contaminated (and moderately contaminated in a small number of cases). The assessment of sediment quality based on I geo, with the regional geochemical background (2.5 mg kg −1 ) adopted as the baseline, results in non-contaminated and moderately contaminated sediments being dominant with a far smaller number of heavily and extremely contaminated ones. Conclusions In the case of several water bodies, Cd concentrations were at record levels that have not been found anywhere else in the world. On the basis of the I geo , sediments of varying quality were found-from virtually uncontaminated to extremely contaminated. The I geo index as an indicator of the quality of bottom sediments is a measure that requires careful interpretation, especially when different concentration levels regarded as natural are used for determining its value.

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