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.

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.

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