Functional diversity of microorganisms in metal- and alkali-contaminated soils of Central and North-eastern Slovakia

Abstract

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<sup>®</sup> 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.

Response of soil environment factors and microbial communities to phytoremediation with Robinia pseudoacacia in an open‐cut magnesite mine

“…The high soil pH induced by Mg contamination is a major determinant affecting the plant's colonization and growth in this Mg‐contaminated soil (Wang, Zhao, Zeng, Hu, & Yu, ; Yang et al, ). Previous research by Fazekaš, Fazekašová, Adamišin, Huličová, and Benková () demonstrated that the original soil pH value of about five caused by magnesite dust contamination was changed to a pH of about 7.2–8.5. In addition, past research in northern Spain has investigated that the soil pH reaches 9.5 near the magnesite ore calcining plant, and the surface soil pH is most affected (Machín & Navas, ), which was similar to our finding.…”

Activity and Diversity of Microorganisms in Root Zone of Plant Species Spontaneously Inhabiting Smelter Waste Piles

“…Chemical stress caused by high concentration of heavy metals affects the number and metabolic activity of microorganisms in soils. High pollution with heavy metals in soils can decrease microbial diversity or disturb functional activity, which may affect nutrient availability for plants [17][18][19]. However, microorganisms that occur in contaminated soils demonstrate the ability to survive in toxic environments through the development of various adaptive mechanisms [20,21].…”

Secondary enrichment of soil by alkaline emissions: the specific form of anthropogenic soil degradation near magnesite processing factories and possibilities of land management

“…Currently, only several resistant species are present (Fazekaš et al, 2018). In localities most affected by alkaline dust deposition, the vegetation completely disappeared and a tight, solid Mg-rich, 5-8 mm thick crust was formed on the soil surface, inhibiting the proper soil functioning (Hronec et al, 1992;Fazekaš et al, 2019).…”