During the mining process in mines, a problem arises with the formation of coal post-mining waste, which is waste rock. It is often stored by mines on various types of land to manage the resulting spoil. However, this is not without its impact on the soil. In this study, we determined the biological and physicochemical properties of rhizosphere soils of the podzolic type, subjected to waste rock reclamation and without the influence of waste rock (control), differing in the type of agricultural use and type of plant cover: field-monocotyledonous (oat cultivation), field-dicotyledonous (buckwheat cultivation), and wasteland covered with very species-poor vegetation. Research has shown that long-term cultivation (buckwheat) contributed to the elimination (leveling out) of the microbial and biochemical differences. The addition of waste rock significantly reduced the number of microorganisms synthesizing siderophore, especially on wasteland (decreased by 1.5 log₁₀/gDW). The abundant presence of the genera Acidocella and Acidphilum, absent in wasteland without waste rock, in the unused soil under the influence of waste rock was strongly associated with the effect of lowering the pH by waste rock in soil not used for agriculture. Increased levels of 77 types of bacteria were observed in samples from buckwheat cultivation compared to wasteland. The number of microorganisms resistant to heavy metals as well as microorganisms capable of producing specific Fe-binding ligands—siderophores—decreased under the influence of waste rock. Moreover, the dehydrogenase activity in long-term cultivation both under the influence of waste rock and without its influence was at a similar level. In contrast, an almost 100-fold decrease in dehydrogenase activity was observed in soils with oat cultivation and a more than 4-fold decrease in acid phosphatase (ACP) and alkaline phosphatase (ALP) activity. These parameters provide an effective system for monitoring soil health, from inexpensive and fast methods to advanced and precise techniques. The results can be applied to solve the problems associated with coal mining wastes by developing methods for their use in soils with long-term agricultural use.

Hard coal mining activity generates post-mining waste (waste rock). Waste rock is deposited in the environment in large quantities for reclamation of agricultural land. In this study, waste rock was treated as a potential source of metal pollutants. The research material (waste rock, soil, plant roots, and Lumbricidae earthworms) was obtained from sites that had been reclaimed using waste rock as well as sites without waste rock. From each site, 30 individuals (n = 30) were collected, divided into five groups, 6 individuals each. Within the group, individuals were analyzed collectively. The study tested whether selected metals (Cr, Ni, Cd, Ba, Pb, Zn, and Cu) are present in waste rock and whether they can be transferred to the soil, plant root systems, and representatives of Lumbricidae, which are important bioindicators and a source of biomarkers. Particular attention was focused on the assessment of the effects of metals deposited in situ on fatty acids in representatives of Lumbricidae and on selecting a set of fatty acids that can be used as biomarkers of physiological effects, including oxidative stress. A panel of biomarker fatty acids was used, which included a panel of 17 biomarker fatty acids from 35 fatty acids analyzed. To confirm or disprove the usefulness of the biomarker fatty acid panel in earthworms, superoxide dismutase (SOD), catalase (CAT), and thiobarbituric acid reactive substances (TBARS) were determined. The study enabled an effective comparison of reference locations with locations potentially burdened with anthropogenic sediment. The results indicate that selected metals present in the waste rock are transferred to the soil, plant root systems, and soil organisms such as Lumbricidae. Selected metals affected the lipid metabolism of Lumbricidae as stressors, leading to changes in the composition and oxidation of fatty acids. The effect on the physiological state of Lumbricidae depended on the duration of the deposit and the type of use (field, meadow, wasteland) of the land with the waste rock deposit. In earthworms obtained from sites with waste rock deposits, higher contents of biomarker saturated fatty acids and biomarker monounsaturated fatty acids and lower contents of biomarker polyunsaturated fatty acids were found compared to earthworms obtained from sites without waste rock deposits. Only Pb (lead) showed a statistically significant correlation with all analyzed parameters in earthworms obtained from sites with waste rock deposits. The results have significant practical implications for environmental protection management. The proposed set of biomarker fatty acids in Lumbricidae can be used to assess the impact of pollutants and environmental monitoring.

The study determined the effect of selected environmental variables (Cr, Ni, Ba, Zn and Cu) on the potential peroxidation of biomarker fatty acids (FAs) in snails Cepaea nemoralis, both in in situ and in vivo (in laboratory conditions). The following panel of biomarker FAs was used: C16:0; C18:0; C23:0; C18:1 n-9; C20:1 n-9; C18:2 n-6; C18:3 n-3; C20:2 n-6; C20:4 n-6; C20:5 n-3; C22:4 n-6; and C22:5 n-3. Field studies included samples obtained from a location potentially affected by anthropogenic sediment, containing a deposit of waste rock, and from a location without this influence. Waste rock, which is mining waste produced during extraction of bituminous coal, was treated as a potential source of metals. The study tested whether metals deposited in an anthropogenically contaminated environment whose main element is a waste rock deposit can be transferred to the body of land snails. In laboratory conditions, Cr³ ⁺, Ni²⁺, Zn²⁺ and Cu²⁺ ions were administered to snails separately, per os, using a pipette, in a volume of 10 µl per snail, in the form of independent solutions of prepared salts (CrCl₃x6H₂O; NiSO₄x6H₂O; ZnCl₂; CuSO₄). Separate experimental groups were created for each metal, in which three metal concentrations were used: 0.0005 mg Met/ml redistilled water; 0.00075 mg Met/ml redistilled water; and 0.001 mg Met/ml redistilled water. Due to the high toxicity of soluble barium compounds, poorly soluble BaSO₄ was used as the source of this element, which in solid form, in an amount proportional to the other metals, was added to the agar constituting the base of the medium. Regardless of exposure to individual metals, three additional experimental groups were also created in which snails were supplemented with a mixture of the tested metal ions, administered together in equal proportions, corresponding to the three concentrations used. The results indicate that metals affect the physiological response in snails associated with changes in the composition of biomarker FAs, peroxidation (PI) and unsaturation (UI) indices, including potential lipid peroxidation. It is possible to identify a group of FAs which can be useful biomarkers of exposure of snails (Gastropoda, Pulmonata) to these variables, in both natural and laboratory conditions. The search for this type of biomarkers in invertebrates is important in ecotoxicology even in the case of subthreshold levels of environmental pollutants. When using snails as a source of biomarkers in situ, after determining the levels of the pollutants in their natural habitat, in order to determine the synergy or antagonism of these pollutants with elements of the environmental background, for example climate and soil factors, it is worth carrying out comparative testing in a laboratory using supplementation with the same substances in controlled conditions.