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The land subsidence caused by underground mining results in land form transformations in the Silesian Upland, which is located in southern Poland. The aim of the research was to determine the role of subsidence basins as new sedimentary basins and local erosion bases. Detailed research was carried out in selected mining subsidence areas where most extensive and spectacular subsidence basins in the Silesian Upland have formed. As part of the field work, the geological structure of the area was examined and detailed geomorphological and hydrological mapping was conducted. Bottom sediment samples were collected from water bodies and were subsequently subjected to laboratory analyses in order to determine their basic composition and the presence of selected elements. Cartometric measurements were carried out on the basis of the cartographic material collected. The underground extraction of coal in the study area has resulted in far-reaching changes in land forms and in the water cycle. In extreme cases, the area has subsided by slightly more than 25 metres compared to the level prior to the commencement of underground coal mining. The emergence of subsidence basins has caused significant transformations in matter circulation, which are essentially local in their nature. The resulting depressions are endorheic basins where sediments accumulate which contain numerous substances, including toxic metals. [ABSTRACT FROM AUTHOR]

Situated in the central part of the country, Chott El Jerid is the largest periodic lake in Tunisia. The depression is a flat plain lined with Holocene lacustrine sediments, which mostly developed in the form of alluvia and evaporites. Geochemical properties of sediments were tested using the following methods: FUS-ICP, TD-ICP, INAA, Cold Vapour FIMS. As concerns the basic composition, the following substances were identified (average levels): loss on ignition (LOI) - 24.27%, SiO2 - 21.46%, CaO - 20.54%, Na2O - 5.23%, Al2O3 - 4.09%, MgO - 3.52%, Fe2O3 - 1.71%, K2O - 1.47%, TiO2 - 0.28%, P2O5 - 0.09%, MnO - 0.02%. The average sulphur content determined was 8.41%. The average content of trace elements was: 4.0 mg/kg As, 162.0 mg/kg - Ba, 61.5 mg/kg - Br, 25.0 mg/kg - Ce, 7.0 mg/kg - Co, 27.5 mg/kg - Cr, 1.25 mg/kg Cs, 8.0 mg/kg - Cu, 0.55 mg/kg - Eu, 3.8 mg/kg - Hf, 13.05 mg/kg - La, 0.18 mg/kg - Lu, 2.5 mg/kg Mo, 9.0 mg/kg Nd, 10.0 mg/kg - Ni, 9.0 mg/kg - Pb, 55.0 mg/kg Rb, 0.6 mg/kg - Sb, 3.8 mg/kg - Sc, 2.15 mg/kg - Sm, 1616.5 mg/kg - Sr, 4.1 mg/kg - Th, 1.45 mg/kg U, 31.0 mg/kg - V, 11.0 mg/kg - Y, 1.15 mg/kg - Yb, 24.5 mg/kg - Zn, 151.5 mg/kg - Zr. The content of basic components and concentrations of trace elements are good indicators of the quality of bottom sediments in periodic lakes. [ABSTRACT FROM AUTHOR]

Lake Ashi (also called Ashinoko Lake or Hakone Lake) is located on the Japanese island of Honshu near the town of Hakone. The aim of the study was to determine the chemical composition of the bottom sediments deposited in the littoral zone in the eastern part of the lake and to evaluate their qualitative characteristics. Tests were performed using the following methods: FUS-ICP, TD-ICP, INAA, Cold Vapour FIMS. As concerns the basic composition, the following substances were identified (average levels): SiO2 - 46.6%, Al2O3 - 18.7%, Fe2O3(T) - 10.5%, MnO - 0.2%, MgO - 3.2%, CaO - 5.4%, Na2O - 1.8%, K2O - 0.4%, TiO2 - 1.2%, P2O5 - 0.2%, loss on ignition (LOI) - 12.0%. The average sulphur content determined was 0.1%. The average content of trace elements was: 211.0 mg/kg - Ba, 231.0 mg/kg - Sr, 16.0 mg/kg - Y, 75.0 mg/kg - Zr, 296.0 mg/kg - V, 127.0 mg/kg - Cu, 13.0 mg/kg - Pb, 182.0 mg/kg - Zn, 30.0 mg/kg - Ni, 3.0 mg/kg - As, 26.0 mg/kg - Br, 37.0 mg/kg - Co, 73.0 mg/kg - Cr, 2.9 mg/kg - Hf, 0.7 mg/kg - Sb, 7.2 mg/kg - La, 15.0 mg/kg - Ce, 2.7 mg/kg - Sm, 0.4 mg/kg - Eu, 26.4 mg/kg - Sc, 2.4 mg/kg - Th, 2.2 mg/kg - Yb, 0.2 mg/kg - Lu, 176.0 µg/kg - Hg. Concentrations of several of the elements analysed (Be, Ag, Cd, Bi, Au, Cs, Ir, Mo, Rb, Se, Ta, W, Nd, U, Tb) were not determined because they were present at levels not exceeding the lower limit of detection of the determination methods used. In the case of most components, it was found that the chemical composition of sediments corresponds to their natural concentrations in the environment and supply from human sources is limited to certain elements, e.g. Br, Hg, Zn, Cu, As, Sb and V. [ABSTRACT FROM AUTHOR]

The Kamchatka Peninsula, located in a subduction zone, is among the most seismically active regions of northeastern Asia. Tenerife is the largest island of the Canary Islands. In August 2008, a fieldwork exercise was performed on a small number of volcanic lakes near the Mutnovski and Gorely volcanoes in southern Kamchatka. For comparison purposes, analogous chemical compounds and elements were determined in marginal deposits collected from three sites in a volcanic area of Tenerife in 2010. Bottom sediments were sampled for laboratory testing. The peculiar morphological characteristics of the lakes and physico-chemical properties of their waters have a profound influence on the chemical composition of their bottom sediments in Kamchatka. Silica was found to dominate at an average content of 53%, followed by aluminium oxides at ca. 15% and by iron oxides at 7.5%. No significant differences were found between the lakes in this respect. Other chemical compounds were found in much smaller quantities, whose presence is demonstrated by the losses during heating that varied from 4.7% to 18.29%. The presence of increased quantities of many rare elements (e.g. barium, strontium, vanadium and zirconium) suggests a violent geological past in an area where the products of volcanic eruptions emerged to the surface and that the geology of the area is varied. In the sediments collected in Tenerife silica dominated. In two samples, it accounted for more than 50% of total sediment mass, and in one case its content was close to 33%. In all samples, aluminium oxide content was comparable to that present in the sediments collected in Kamchatka. In general, this also applied to iron oxides; in sediments collected from the lake located in the caldera in Tenerife, their amount was slightly larger and exceeded 10% of sediments by weight. In two cases, loss-on-ignition values were almost identical to those obtained for the sediments found in the lakes located in the crater of the Gorely Volcano in Kamchatka. A much higher organic substance content of nearly 25% was exhibited by sediments in the aforementioned lake in the caldera in Tenerife. However, a completely different pattern emerged with respect to individual elements in the samples collected in Tenerife. In these samples, sulphur only had a marginal share and zirconium was found in the largest quantities. Much higher concentrations were found for elements such as zinc, rubidium, lanthanum, cerium, neodymium and hafnium. This significantly differs from the sediments analysed in Kamchatka. Only barium and strontium were present in comparable amounts in both Tenerife and Kamchatka. [ABSTRACT FROM AUTHOR]

The Silesian Upland (southern Poland) is an area where underground coal deposits as well as zinc and lead ores are mined (in the past, iron ores were exploited there as well). Subsidence basins form in places where minerals are mined below the ground surface. Purposes of the study included assessing the impact of underground mining on the rate of surface subsidence, examining the conditions in which water bodies form in subsidence basins and determining the role of such basins in shaping habitat conditions and biodiversity. Within the framework of field work, detailed geomorphological and hydrological mapping was carried out, floristic composition was determined and the animals present in the area were characterised. Cartometric analyses were carried out based on the cartographic material collected. Laboratory tests were also conducted with respect to both water (using the potentiometric, spectrophotometric, turbidimetric and flame photometry methods) and sediments (using sieve analysis, the combined areometric-sieve method, INAA and ICP). The study revealed that in the region, a total area of more than 1000 km² is threatened with ground deformation and the depth of some basins exceeds 30 meters. Water bodies at the bottom of subsidence basins exhibit morphometric parameters that depend on the size of the subsidence and their shorelines are most often oval in shape. Very small and small water bodies prevail. A vast majority of them have areas which do not exceed 10 hectares. They are also fairly shallow (usually up to 2-3 metres) and greater depths are very rare. Water bodies in subsidence basins alter the local water cycle significantly. These hydrographic phenomena are undoubtedly a new element that contributes to changes in the direction of water migration in the area in question. The water bodies examined were subject to transformations at each stage of the development of the subsidence zone. It has been found that they set a new erosion base level and act as local sedimentary basins. The bottom sediments accumulated in such water bodies are significantly contaminated, particularly with heavy metals such as lead, zinc and cadmium. The studies conducted have demonstrated that these water bodies may fulfil functions similar to natural lakes. The changes triggered by land subsidence affect the evolution of vegetation, and in the final stage, aquatic and land vegetation ecosystems are shaped. In the wake of these changes, many new animal species, both vertebrates and invertebrates, migrate into the area. [ABSTRACT FROM AUTHOR]

The paper covers transformation processes taking place in subsidence basin lakes in the Silesian Upland, southern Poland. In the Silesian Upland collapsing underground cavities produced in the process of the mining of mineral deposits (hard coal, zinc and lead ores and iron ores) cause gradual or violent subsidence of the ground surface. Geomorphological and hydrological mapping and map-based surveys reveal that the combined area exposed to this type of deformation covers more than 1000 km² and that this deformation results in the formation of basins 30 metres deep or more. The morphometry of water bodies filling subsidence basins is similar to that of the cavities themselves and the waterlines tend to be oval in shape. Small and very small water bodies dominate and a clear majority are 10 hectares in area or less. They are very shallow with very few examples deeper than 2-3 metres. The hydrochemical diversity of these water bodies is determined by the nature of their catchment areas. Research shows that their waters are commonly eutrophic. The presence of biogenic compounds is also a characteristic feature. The severe degradation of water quality is also evidenced by high salinity levels. The water bodies are also characterised by high levels of heavy metal pollution in their bottom sediments. Zinc, lead and cadmium stood out particularly with their concentrations often exceeding the geochemical background levels adopted. [ABSTRACT FROM AUTHOR]