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The bioavailability of heavy metals in the soil is a function of their speciation. The speciation of Zn in Technosols of anthropogenic anomalies in Southern Urals and Southern Russia was studied using X-ray absorption spectroscopy and X-ray diffraction methods based on synchrotron radiation. The studied Technosols are characterized by exceedings of the lithosphere clark for Zn in hundreds of times. Hypergenic changes in the mineral composition of Technosols revealed different types of Zn surrounding. In the Southern Ural soils, six oxygen atoms forming a deformed octahedron coordinate Zn. For contaminated Technosols of Southern Russia, the longs of the Zn–O bonds were determined, which are close to the bonds in ZnSO 4 , and the mixed version of local surrounding with Zn–S and Zn–O bonds. Studies of metal speciation are of extreme importance for revealing the main mechanisms responsible for the mobility of trace elements such as Zn and understanding its consequences in terms of long-term potential emission by the Technosols. • The studied Technosols are characterized by the high level of Zn pollution. • Molecular-structural changes of Zn revealed in Technosols of anthropogenic anomalies. • Zn forms a deformed octahedron by six –О– atoms in Technosols of Southern Ural. • Local surrounding with Zn–S and Zn–O bonds revealed in Technosols of Southern Russia. [ABSTRACT FROM AUTHOR]

The determination of the bulk chemical composition of sulphide-containing soils and badland soils causes difficulties by X-ray fluorescence (XRF) analysis: the content of sulphur is underestimated. The inability to determine the main element, oxygen, is the reason for errors in the XRF bulk chemical analysis of the badland soil. A procedure is proposed for the adjustment of oxygen content in the solid phase of the badland soils using Mössbauer spectrometry data on the content of Fe minerals. The contents of total iron, sulphur, and oxygen in the soils can be corrected in the case of simple iron mineralogy. After correction, the total content of sulphur measured by XRF significantly increases and that of oxygen decreases. The clarified oxygen content of the solid phase of badlands soil can be used to characterize the degree of their degradation. [ABSTRACT FROM AUTHOR]

Human activity, such as mining, is often detrimental to the environment. For risk assessment of polluted soils, it is crucial to establish the speciation of the contaminants such as zinc. The aim of the work was to identify the Zn species in contaminated anthropogenically transformed soils known as 'spolic technosols'. The Zn speciation in technosols was studied using a combined fractionation scheme and a set of X-ray synchrotron methods. Spolic technosols within the Karabashmed Company zone of the southern Urals have a very high level of Zn contamination. The role of soil components in metal fixation in both the loosely and firmly bound states were revealed. Iron oxides actively participate in the immobilization of Zn. The stud? of the local structure of technosols by X-ray absorption spectroscopy showed that Zn is coordinated to six oxygen atoms forming a distorted octahedron with Zn-O bond lengths close to those in ZnSO4. The presence of short bonds, formed by Zn atoms, has been also revealed. Thus, the application of two independent methods can be helpful in defining Zn speciation in polluted soils. [ABSTRACT FROM AUTHOR]