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Soil iron and manganese fractionation is evaluated in the soil profile sampled from a pine-covered area of Wielkopolski National Park (mid-western Poland), that for years has been exposed to acid rain. The soils studied are sands and loamy sands with a pH of 3.3-4.4. The content of iron and manganese was analyzed by sequential extraction in the following fractions: exchangeable, acid extractable, reducible, oxidizable, and residual. The soil profile displays a lithogenically dichotomous structure that is reflected in the iron and manganese content, especially in the Fe residual fraction and Mn oxidizable fraction. In terms of the lability of manganese, it can be stated that the amount of manganese in reducible fractions (Mnred) is higher than in exchangeable and acid extractable ones (except in the surface layer), while the amounts of manganese in fractions in which it is poorly available (Mnox) and unavailable (Mnres) are lower than that of Mnred. For iron, this sequence looks as follows: Feex
The total content and available forms of trace metals (Cd, Cr, Cu, Ni, Pb, Zn) in fluvial sediments has been determined for surface samples (0-30 cm) collected in 2009 and after the flood in 2010 from the flood plain of the Odra River in western Poland. Total metal concentrations were obtained after mineralization with HNO₃, and the available forms of trace metals were obtained by single extraction procedure using soft extractant – 0.01M CaCl₂. Measurements of physico-chemical parameters also were performed: grain size fraction analysis, Eh, pH, organic matter, and calcium carbonate contents. The conducted analyses revealed that metal samples collected after the flood in 2010 varied in terms of physico-chemical parameters, total contents, and actually available forms of the studied trace metals. It has also been stated that the total contents of Cd, Cr, Cu, Ni, Pb, and Zn are strongly correlated with the participation of very coarse-grained (from 2000 to 1000 µm) and medium-grained (from 500 to 250 µm) sediments as well as with the content of organic matter (excluding Cd). On the other hand, the actually available Cr forms may increase along with the increase in CaCO₃ content.
A laboratory simulation of acid rain was performed in which soil monoliths from the Wielkopolski National Park area were sprinkled with water solutions of sulphuric acid of pH 3.0 or 2.0, and for reference with distilled water of pH 5.6. The form and amount of the washed out aluminium as well as changes in the chemical properties of the soil studied were determined. The process of aluminium release proved particularly dangerous for acidic or slightly acidic soils which cover a large part of the National Park area.
Investigations were carried out on sandy forest soils from Wielkopolski National Park (west-central Poland), which have been exposed for a long time to anthropogenic pressure. Two comparative extract recovery methods were performed for aqueous soil extracts (ME) at ratios 1:1, and those obtained from so-called saturated paste (MP). Recovered extracts were analyzed for sodium, potassium, magnesium, calcium, aluminium, chloride, fluoride, nitrate and sulphate concentrations, at various depths of two slightly different soil profiles. Higher levels of alkaline cations were obtained in extracts recovered at ratios 1:1, in the case of sandy soils along the entire profile, whereas in profiles with variable lithology, the granulometric composition clearly affected the mechanism of ion release. The patterns of changes in the contents of chlorides and sulphates were similar to those of calcium and magnesium, while fluoride levels in the topsoil differed significantly, depending on the method applied. Differences between the two methods were also significant in the case of aluminium content. The elaboration of aluminium toxicity indices should consider such approaches.
Floodplains are places of accumulation and secondary release of metals. The polluted water sediments which are stable during normal river flows can erode in the times of floodings and high water stages. In such periods, the pollution of the bad sediments, river waters and the floodplains increases. In environmental research, determining the total metal content does not provide information about their mobility or availability. The toxic effects depend on their chemical form. In this paper, single extraction procedures have been used to determine the forms of easily available metals. Three types of extractants have been used: neutral salt solution (0.01M calcium chloride), mineral acid solution (0.1M chydrochloric acid) and complexing reagents (0.02M ethylenediaminetetraacetic acid (EDTA) and 0.005M deiethylene triamine pentaacetic acid (DTPA)), to determine the extraction effectiveness. The study presents the results of preliminary research of pollution with selected metals (cadmium, chrome, copper, nickel, lead, zinc, iron and manganese) of the Middle Odra Valley. Higher total concentraions of metals were found in the areas currently flooded by the Oder River.
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