Spatial distribution and geochemistry of major and trace elements from Mohos peatland, Harghita Mountains, Romania

摘要

The Mohos peatland is used as environmental archives of deposition for major (Al, Ca, Mg, Fe, and Mn) and minor elements (Cr, Cu, Ni, Pb, Sr, and Zn). The intense mining activity of Cu-rich pyrite and polymetallic sulfide ore from Balan districts during the past centuries with a strong pollution impact was the reason why the Mohos peatland, located in the vicinity of a mining area, was selected for this study. The mineralogical and chemical compositions of the peat have been determined by inductively coupled plasma optical emission spectrometry (ICP-OES), scanning electron microscopy (SEM), and x-ray diffraction (XRD). The identification of the main processes affecting the concentrations of the elements in peat was statistically evaluated by principal component analysis (PCA), and the identification of the main groups was determined by hierarchical clustering analysis (HCA). Our results revealed that the source of chemical and mineralogical peat samples is mainly geogenic with most of the elements being accumulated following the disintegration of parental material and through volcanic activity. For Pb, Zn, Ni, Al, and Sr, the concentrations were influenced by both natural processes and anthropogenic activities, such as mining, burning of fossil fuels, traffic activities, and metallurgy. Copper was influenced by anthropogenic activities. The distribution maps of trace elements were built only for the area in which the samples were taken.