Soils in areas of mining and smelting of Pb-Zn ores in Southern Poland are strongly enriched in heavy metals (Zn, Pb, Fe, Cd, Tl, As). The highest concentrations of Zn (<55,506 mg kg −1 ), Pb (<8,262 mg kg −1 ), Cd (<220 mg kg −1 ) and Tl (<67 mg kg −1 ) are linked to the fine fractions of upper soil layers in sites contaminated by past exploitation and processing of ores. The high stress of metals, and the negative influence of acid waste drainage has limited the development of flora and fauna in these areas. The increasing ability of plants to grow is due to the positive symbiotic action of fungi and bacteria. The mycorrhizal communities were identified in rhizospheres rich in unstable ZnPb-Fe sulphides such as sphalerite, galena, pyrite and marcasite and carbonates of Zn (smithsonite) and Pb (cerussite). They occur in associations with sulphates, e.g., gypsum. In parts of fungi, secondary mineral phases containing Zn, Pb, Fe and Mn occur. Metalbearing aggregates formed during symbiotic action between myccorhiza and bacteria connected with them. They enhance the binding of bio-available ions of Zn, Pb and Mn in the most unstable phases. Metal contents in the mycorrhizal parts of the rhizospheric soils were determined by Atomic Absorption Spectroscopy. Mineralogical investigations involved X-ray diffraction, scanning electron microscopy with energy dispersive spectrometry.
A self-heating intensity index (SHII) based on the highest (pixel max.) and lowest (pixel min.) values taken from satellite thermal maps of burning coal waste dumps are proposed. The index enables the classification of such fires in Ukrainian- and Polish coal waste dumps. Both in Ukraine and in Poland, varying thermal intensities during 1985–2019 are revealed, using the SHII and following thermal intensity threshold values, namely, extreme thermal activity (> 7), advanced (3–7), moderate (3–1.5), initial (1.5–1), no activity (< 1). The SHII shows decreasing thermal activity in the selected Ukrainian coal waste dumps during 2017–2019. It aids in reconstructing the thermal history of the dumps. Analysis of satellite images revealed a large number of burning coal waste dumps in the Donetsk Coal Basin (Ukraine) with high thermal activity. Such burning likely reflects large amounts of organic matter and sulphides in the dumped material subjected to self-heating and self-burning processes, lack of compaction of the coal waste and/or high methane contents. Comparison of SHII values calculated from satellite- and drone thermal-camera images were compared to show that SHII from drone thermal images have much higher values than those from satellite images; the former have better resolution. Thus, SHII from Landsat- and drone images should be used separately in dump heating studies.
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