Laboratory Determination of the Solid Phase Composition of Technogenically Salinized Peatlands: Possibilities and Limitations

Abstract

A laboratory study of the solid phase of saline peats by X-ray fluorescence (XRF) analysis has revealed the presence of organic halogen compounds. Cl-organic compounds were found in one-third of peat samples; however, their proportion was low: 14–15% of the total chlorine content. In contrast, Br-organic compounds are formed more often and the Brorg proportion is higher (from 12 to 23% of total Br). The relatively weak development of the halogenation of organic matter in the saline peatlands is explained by recovery conditions that prevent the synthesis of organic halogen compounds. An X-ray diffraction analysis (XRD) of the ash of saline peatlands has revealed four main minerals: halite, quartz, calcite, and gypsum. Halite absolutely prevails in low-ash peatlands. The XRD confirms the salinity of peatlands and gives the quantitative content of three minerals: halite, quartz, and calcite. However, analysis of peat ash may involve errors both due to the growth of minerals (gypsum) and due to the incomplete identification of the number of phases in high-ash peat samples. The second type of error can be corrected using data on the chlorine content in peat ash by X-ray fluorescence analysis. In addition to the construction of profiles of salt distribution in solution, it is necessary to determine the amount and composition of organic halogen compounds (some of them have herbicide properties) for characterizing the contamination of peatlands.