Geo-Ecological Assessment of the Prospects of Using Coal Mining Waste as a Soil Substrate in the Arctic Conditions

The technogenic transformation and the natural potential of coal industry waste allow the latter to be used in the reclamation of disturbed lands. Technogenic soils are sources of chemical substances, which are included in natural processes and create a special kind of natural and technical systems. At the same time, the most sensitive indicator of the stress impact of anthropogenic factors in an urban environment are woody plants. The aim of the study was to investigate the ecological state of technogenic soils and the prospects of using coal washery rejects in land reclamation in the Arctic conditions. The objectives of the study were to determine the gross concentrations of heavy metals in Vorkuta technogenic soils formed by coal sludge, as well as to assess their impact on the growth and development of woody vegetation. Object and methods.
The object of the study was technogenic soils from flowerbeds installed in the central part of the city of Vorkuta. Microprobe X-ray spectral analysis was used to determine the gross concentrations of heavy metals in the samples. To assess the condition of tree seedlings, a visual inspection of the needle foliage (yellowing and defoliation) was performed, and the young shoot lengths were measured. Results. All of the studied soils are characterized by high total iron content. The zinc content in the soil samples taken from the flowerbeds located along Gagarina St. and near the City Administration building exceeds the approximate permissible concentration, APC (110 mg/kg). The soil from flowerbeds near the City Administration building contains increased copper and cadmium contents as compared to APCs (66 and 1.0 mg/kg, respectively). The concentration of lead in the soil samples does not exceed APC (65 mg/kg). The study of large-sized seedling showed that the best condition of large-sized seedlings of Norway spruce (Picea abies) with no signs of browning or defoliation was observed in the flowerbeds on Gagarina St. and near the City Administration building. Significant damage to needles was found in the sites opposite the ‘Olympus’ and in front of the ‘Vorkutaugol’ JSC building. Conclusion. The study revealed the possibility of using coal mining waste as a soil substrate for flowerbeds of the city. The gross concentrations of heavy metals in the technogenic soils of the flowerbeds located in the central part of Vorkuta were studied. The research of the impact of technogenic soils formed by coal mining waste on the condition of large-sized Noprway spruce seedlings did not reveal any unambiguous patterns.