This research was performed at Petrovsky waste rock dump, the Central part of the Kryvyi Rih iron-ore & metallurgical district (Dnipropetrovsk region, Ukraine). The macronutrients (K, Ca, Mg, P and S) and heavy metals (Fe, Mn, Zn, Cu, Pb and Cd) contents in the leaves of three species of the trees (Ash-leaved maple, Silver Birch and Black locust) that were collected on devastated lands were assessed. It was established that trees which grow on the Petrovsky dump take place under evident shortage of nutrients (especially K and P) and excess of metals (especially Fe, Mn and Zn). It is revealed that Ash-leaved maple and Black locust are more resistant to the geochemical conditions of devastated lands. In this regard, these species of trees can be recommended for forest restoration & reforestation on devastated lands.

he relevance of the research is due to the need to develop technologies for phytoremediation of the devastated lands in the mining and metallurgical regions of Ukraine and the world. In this regard, the creation of tree plantations adapted to the ecological conditions of such territories is considered by many experts as the most promising option for innovative technologies. However, the development of artificial woodlands requires knowledge of the pedogeochemical characteristics of devastated lands. The aim of the work was to carry out a comparative analysis of the macronutrients and heavy metals gross forms content in the soils of the devastated lands of the Kryvyi Rih mining and metallurgical region. The field studies focused on five contrasting monitoring sites of the Petrovsky dump (Central Kryvorizhzhya), which has a typical age and composition of rocks for the region. Soil sampling, drying, sieving, and sample preparation (sintering in a muffle furnace) were done in accordance with classical techniques. The concentrations of macronutrients (potassium, sodium, calcium, magnesium, sulfur, and phosphorus) and heavy metals (iron, manganese, zinc, copper, lead, and cadmium) were determined using an Inductively Coupled Plasma Mass Spectrometry (ICP- MS) X-Series 2 (Thermo Fisher Scientific, USA). The analytical part of our research was carried out on the basis of the laboratory of the Institute of Biosciences, Freiberg University of Technology and Mining Academy (Freiberg, Germany). At monitoring sites, significant differences were found in the content of macronutrients gross forms, and their variation relative to the control values as well. Potassium and sodium concentrations generally differed slightly or were close to control levels. The results of determining the content of calcium, magnesium and phosphorus indicate a significant deficiency or excess of these macronutrients in the soils of the devastated lands. An increased sulfur content was found in the soils of all monitoring sites, in some cases 4 times higher than the control level. The measured content of gross forms of iron, manganese, copper, cadmium and, partially, zinc in the soils of different monitoring sites exceeded the control values by 5.5 – 5.9 times. Thus, the analysis of the research results made it possible to establish that the soils of the devastated lands of the Petrovsky dump are characterized by unfavorable properties for the growth of most species of woody plants.

Assessment of heavy metals content in the initial soils of the post-mining landscapes plays an important role in pollution control, ecological protection, and safe-guarding human health. In this study, the site-specific pedogeochemical background contents of several metals in soils in Kryvyi Rih Iron Ore Mining & Metallurgical District (central part of Ukraine) were determined. The metal concentrations in the soils of Petrovsky waste rock dump were also quantified and were also assessed using indices of pollution. The field sampling was carried out at a depth of 0-10 cm in five plots in dump area and in one plot in control site. The 43 soil samples were collected. The results showed that local background concentrations of heavy metals in soils of studied area decreased in the following order (mg×kg−1): Fe (42 510) > Mn (761.7) > Cr (94.48) > Zn (90.51) > > As (31.85) > Cu (28.10) > Pb (18.73) > Co (16.21) > Sn (4.64) > Mo (0.28) > Cd (0.16). In the initial soils of devastated lands at Petrovsky waste rock dumps the predominance of increased Cd, Co, Fe, Mm, Mo and Sn content and the predominance of decreased As, Cr and Pb content were observed. Based on the mean values of the individual indices of pollution (Pollution index, Geoaccumulation index, Enrichment factor, Contamination factor) can be assumed that in these soils As, Cd, Fe, Mo, Pb and Sn are mostly coming from industrial activities. Co, Cr, Cu, Mn and Zn are mostly related to their natural occurrence in devastated lands. The values of integrated indices of pollution (Nemerow pollution index, Pollution load index, Degree of contaminated, Modified degree of contamination) indicated that the initial soils of post-mining landscapes can be evaluated as no polluted – and extremely heavy polluted.

Knowledge about the content of phenolic compounds in tree leaves growing on devastated lands may be important for foresting of the post-mining landscapes and for improving environmental quality in industrial areas. The object of this study was on standpoint of an ecosystem approach to determine the phenolic compounds concentrations in the leaves of the trees that grow naturally on the devastated lands at iron waste rock dump. Petrovsky waste rock dump areas at Kryvyi Rih Iron Ore Mining & Metallurgical District (central part of Ukraine) were chosen for the present research. During 2017–2021, the 5 research plots in the dump’s area and 1 research plot in the background area (natural ecosystems of the Hurivskyi forest, Kirovohradska oblast) were established. The content of phenolic compounds was investigated in the leaves of three woody plants species: silver birch (Betula pendula Roth.), ashleaf maple (Acer negundo L.) and black locust (Robinia pseudoacacia L.). The extracts of leaves were prepared by extraction of 80% isopropanol. The phenols concentration was determined using Folin-Ciocalteu reagent. The absorbance was measured by spectrophotometer at wavelength of 725 nm. The calibration curve was constructed using standard solutions of gallic acid. The phenols concentration was expressed as gallic acid equivalents in milligrams per gram dry weight of plant material (mg GAE * g-1 dw). The results showed that in background area the values for phenolic compounds content vary within minimal limits: from 26,90 to 27,49 mg GAE * g-1 dw in leaves of silver birch, from 17,53 to 18,11 mg GAE * g-1 dw in leaves of ashleaf maple and from 10,98 to 11,65 mg GAE * g-1 dw in leaves of black locust. In all the samples, the concentrations of phenolic in the leaves of silver birch and black locust were generally within natural limits. The concentrations of phenolic in the leaves of ashleaf maple were below the natural levels. According to the leaves analyses, the phenolic compounds content in all woody plants species from all research plots on the devastated lands were statistical significant differences than the reference samples (P < 0,05). The levels of phenolic in samples of ashleaf maple and black locust were found to be greater (P < 0,05) than the background values about 15–65% and 115–165%, respectively. The concentration of phenolic in leaves of silver birch was lower (about 10–28%, P < 0,05) than those values recorded as control. The woody plants species according to resistance to the devastated lands of the Petrovsky waste rock dump were in the following decreasing order: silver birch (Betula pendula Roth.) > ashleaf maple (Acer negundo L.) > black locust (Robinia pseudoacacia L.).