Mining activities have resulted in the existence of dumps, which generally present a perpetual danger of moving and transforming toxic elements. The experimental study was carried out in Nizna Slana (Slovakia) where the main source of emission was the iron-ore mining–processing factory focused on siderite mining. Siderit from Nizna Slana is highly ferrous with an increased level of the Mn content. Among the undesirable impurities on the deposit are mainly As, S, Pb, and Zn. According to the environmental regionalization of the Slovak Republic, the surveyed area represents a region with a slightly disturbed environment. The BIOLOG® Eco plates method was used for ecotoxicological evaluation of contaminated soils, where soil enzymes (acidic and alkaline phosphatase and urease) were also monitored in soils and soil contamination was evaluated according to Hakanson (1980). Based on the results obtained, it can be concluded that the content of Hg, Cd, Cr, Cu, As, Fe, Mn, and Mg is above the toxicity level. As, Fe, Mn, and Mg are the most serious pollutants in the area under investigation, and their pronounced excess indicates contamination, where harmfulness and toxicity can be expected. Based on the evaluation of the contamination factor and the degree of contamination, the soils in the emission field of old mining works are very highly to slightly contaminated with heavy metals. The experimental results in the real environment showed that the activity of soil enzymes showed considerable differences, and, regarding the functional diversity of soil microorganisms, we have not seen significant spatial variability.

This paper is focused on the impacts of alkaline and metal deposition on soil and vegetation in the immission field of magnesium factory Jelšava-Lubeník (Slovakia). Soil samples and the foliage of vegetation were obtained from the Jelšava-Lubeník area with specific alkaline pollutants. The examined area is one of the most devastated regions of Slovakia. From the point of view of environmental regionalization, it belongs to an environmentally damaged area of Category 3. The total content of heavy metals in the soil and vegetation (Pb, Zn, Cr, Mn, Mg) were determined by atomic absorption spectrometry and X-ray fluorescence spectrometry. Soil reaction was determined in a solution of 0.01 M CaCl2. Vegetation was assessed by the Braun-Blanquet scale. In conclusion, we can say that spray particles of free magnesium oxide (MgO) strongly influence soil reaction, diversity, and vegetation cover. The research showed that the investigated sites were mostly strongly alkaline; the contents of Cr, Mn and Mg were over the toxicity limit, while the measured values of Pb and Zn did not exceed the limits set by the law. The values that measured significantly above the set limit show contamination that can be considered harmful and toxic. In the monitored species, that is, Agrostis stolonifera, Elytrigia repens and Phragmites australis, an over-limit content of Pb and Zn and toxic contents of Mg and Mn were found.

A high content of heavy metals in the soil and plants of a magnesite mining area might cause serious damage to the environment and can be a threat to the health of the surrounding population. This paper presents the results of research that focused on analyzing the heavy metal content in soil and plants in the dumping grounds of the magnesite mining factory Jelšava-Lubeník (Slovakia). The analysis focused on the content of heavy metals in soil (X-ray fluorescence spectrometry, atomic absorption spectrometry), in plants (inductively coupled plasma mass spectrometry, inductively coupled plasma atomic emission spectrometry), and pH (1M KCl solution). The results showed that the soil in the study area was slightly acidic to strongly alkaline and the content of Cr, As, Mn, and Mg exceeded by several times the limit values for the Slovak Republic. The results of the hierarchical cluster analysis and the correlation analysis show that the grouped metals come from the same sources of pollution. The content of heavy metals in plants was high and the highest concentration was found in the roots of Elytrigia repens > Agrostis stolonifera > Phragmites australis and flowers of Phragmites australis. The findings confirmed the suitability of the used plants in the process of phytoextraction and phytostabilization. The acquired knowledge can help in planning and realization remediation measures and improve the state of the environment in areas exposed to magnesite mining.

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Landfills, old and abandoned mines, industrial sites, heaps, sludge ponds and other sources of pollution represent environmental threats and are characterized as chemical time bombs. This work is focused on the evaluation of soil contamination by risk elements using various indices (geoaccumulation index—Igeo, enrichment factor—EF, contamination factor—Cif and degree of contamination—Cd). These selected agrarian problem areas are located in Slovakia, especially in the air pollution field of landfills consisting of power plant fly ash, tannery and footwear wastes, leachate (lúženec), iron ore slag, waste from metallurgy and sludge ponds in which coal sludge waste is deposited and waste from ore treatment. Nine research sites in the agrarian region of Slovak Republic were monitored. Ten risk elements (Fe, Mn, Zn, Cu, Co, Ni, Cr, Pb, Cd and Hg) and pH/H2O were included in this study and were determined in surface soils (of 0.05 m to 0.15 m) using atomic absorption spectrometry (AAS). Our study showed the highest exceedance of the limit values of risk elements in the order Ni (51.85 times) > Co (25.47 times) > Cd (13.70 times) > Cu (12.78 times) > Cr (8.37 times) > Fe (8.26 times) > Hg (7.94 times) > Zn (5.71 times) > Pb (4.63 times). The content of risk elements increased based on the average values of Igeo in the order of Cr < Hg < Zn < Pb < Ni < Cu < Cd. Igeo values for cadmium indicated mild-to-extreme contamination at all sites. We found the most significant enrichment in the order of Cd > Cu > Pb > Ni > Zn > Hg > Cr. EF values for cadmium indicated extremely high enrichment; the Cif and Cd values indicated a very high degree of soil contamination near the nickel smelter landfill, an industrial metallurgical plant and old but active mines. The studied areas pose a serious danger not only to the soil but also to groundwater and biota due to the prevailing low soil reaction, which increases the mobility of toxic elements. The study provides important results for the development of effective strategies for the control and remediation of endangered areas.

A field-based study and laboratory tests were undertaken to determine the functional diversity of microorganisms in metal- and alkali-contaminated soils in Central and North-eastern Slovakia where iron ore and magnesite have been mined and processed for a long time. To improve the understanding of the functional diversity of microorganisms, we examined the effects of environmental factors on the functional diversity of microorganisms in metal- and alkali-contaminated soils in the emission field of heaps and tailings impoundments of iron ore mines (Central Spiš) and magnesite factories (Jelšava and Lubeník). Biolog^® Eco Plates were used to determine and assess metabolic profiles of microbial communities. The examined area of Central Spiš showed extremely high values of Hg and Cu and the values of Zn, Cd, Pb and Cr exceeding the permissible limit were determined. Soil reaction was extremely acidic to strongly acidic. The Jelšava and Lubeník area was characterized by alkaline contamination and the soil reaction was slightly acidic to strongly alkaline. The values of Cr, Mn, and Mg exceeding the permissible limit were measured there. The results indicate harmful and even toxic contamination. Our results showed that the diversity of microorganisms was different in the investigated areas and it was significantly influenced by environmental factors such as soil reaction, bulk density, porosity, and heavy metals Hg, Pb, Cr, Zn, Cu, Mn and Mg. Based on the results of the Shannon index, we can conclude that the diversity was low to moderate (2.5–3.3) and medium (3.3–4.0). Correlations between functional diversity of microorganisms and soil reaction, Hg, Cr, and Cu were determined. Our findings are decisive for understanding the microbial diversity in metal- and alkali-contaminated soils and they can be used to assess the quality and health of soil, as well as for scientific applications of remediation techniques.

Phenological observations record the dynamics of vegetation in relation to meteorological conditions as well as the long-term trends in relation to climate change. We processed 20-year data of the flowering (BBCH scale 60), leaves unfolding (BBCH 11) and ripening of fruits (BBCH 86) of four woody species in south-west and central Slovakia. The phenological year begins with the flowering of the hazel. This phenophase has the largest amplitude of onset (52-65 days) as well as interannual variability (s x = 20.2-33.4%) as it enters an unstable condition in early spring. At all stations, the order of phenophases is the same from the end of April. We found the highest vertical phenology gradient of the BBCH 60 Tilia cordata Mill. (6 days/100 m) and the smallest of BBCH 11 T. cordata (2.4 days/100). The statistically significant trends (p < 0.05) in shifting to the earlier period were in BBCH 60 Crataegus oxyacantha L. (0.4-0.5 days per year), BBCH 86 Corylus avellana L. (0.6 days per year), BBCH 60 Prunus spinosa L. (0.5-0,6 days per year) and BBCH 11 Prunus spinosa L. (0.6-0.7 days per year). These shifts indicate the change in the onset of the phenophases in south-west and central Slovakia.

Mining activities, ore concentrations, and transport processes generate large amounts of pollutants, including hazardous elements, which are released into the environment. This work presents the results of experimental research aimed at evaluating the environmental risks of soil and plant contamination in two magnesite mining and processing areas in the Slovak Republic, and assesses the phytoremediation potential of dominant plant species. Eleven potentially toxic elements in the soil were investigated using X-ray fluorescence spectrometry (Cd, Pb, Cr, Zn, Cu, As, Ni, Mn, Mg, Fe) and atomic absorption spectrometry (Hg). In plants, potentially toxic elements were investigated using inductively coupled plasma mass spectrometry (Cu, As, Cd, Pb) and inductively coupled plasma atomic emission spectrometry (Cr, Zn, Mn, Mg). Selected soil parameters (pH, redox potential, and soil organic matter) were also investigated. Soil contamination was evaluated using environmental indices (geoaccumulation index—Igeo, enrichment factor—EF, contamination factor —Cf, degree of contamination—Cd). The phytoremediation potential of plants was evaluated using the bioconcentration factor (BCF) and the translocation factor (TF). The soil reaction in the studied areas indicated a strong alkalization of the soil. The soils in Jelšava-Lubeník were significantly contaminated with Cr, As, Mn, and Mg. The most significant enrichment based on the average values of EF was found to be in the order of Cd > Mg > Zn > Cu > As > Cr > Ni > Pb > Fe > Hg > Mn. The observed values of Cf and Cd indicated a high degree of soil contamination. In Košice, the soils were found to be significantly contaminated with Cr, Mn, Mg, and Ni. The most significant enrichment was found in the order of Cd > Mn > Ni > Pb > Zn > Mg > Cu > As > Fe > Cr > Hg. Very high Cf was found for Pb and Cr. The results of correlation and hierarchical cluster analyses suggest a similar origin of pollutants caused by significant anthropogenic interventions due to magnesite mining and processing. The investigated dominant plant species, Phragmites australis, Agrostis stolonifera, Elytrigia repens, and Taraxacum officinale are able to accumulate high concentrations of the monitored potentially toxic elements without more serious load or damage. The results of BCF and TF confirmed that P. australis and T. officinale appeared to be suitable accumulators in the phytoextraction process. In the case of E. repens and A. stolonifera it was confirmed that they accumulate and immobilize high concentrations of potentially toxic elements, especially in the roots, establishing the suitability of their use in phytostabilization processes.