Search Results (6)

This paper evaluates an experimental wetland as part of a pilot soil reclamation project in a mining area. The wetland was constructed using materials of mining origin from the area; most reactive materials of acid pH were stabilised using limestone filler. The study selected macrophytes that are tolerant to potentially toxic elements (PTEs) and resistant to salinity, namely Phragmites australis, Juncus effusus, and Iris pseudacorus. These macrophytes were then placed in pots containing substrates composed of different mixtures of topsoil, peat, and mining waste (black or yellow sand). A thorough analysis of the physicochemical and mineralogical characteristics of the materials included studies of PTE mobilisation. This study emphasises the significance of the rhizosphere in directing the transfer of PTEs to the plant and the correlation between the substrate and the development of plant defence mechanisms, such as the formation of Fe-plates. Scanning electron microscopy was used to highlight these aspects and validate the results of the analytical determinations. These wetlands can be proposed as a phytoremediation strategy for areas affected by mining and maritime influence. They are easy to construct and remain stable, providing important ecosystem services such as the natural attenuation of acid mine drainage, support for vegetation development and fauna, and a clean ecosystem. Full article

Evaluating how different tree species and substrates affect the microbial and physicochemical properties of technosols from combustion wastes and reclaimed mine soil (RMS) is vital in species selection to enhance restored ecosystem services. This research aimed to evaluate the impact of pioneer and N-fixing tree species and substrates on the post-mining soil microbial and physicochemical properties. Common birch (Betula pendula Roth) and Scots pine (Pinus sylvestris L.), as the commonly introduced species on reclaimed mine soils (RMS) in eastern and central Europe, were selected as pioneer species, whereas black alder (Alnus glutinosa (L) Gaernt.) and black locust (Robinia pseudoacacia L.) were selected as N-fixer species. Soil samples were collected from different RMS developed from three substrates (fly ashes, clay, and sand) and measured for the content of total nitrogen (N_t), organic carbon (C_org), exchangeable calcium (Ca²⁺), exchangeable potassium (K⁺), exchangeable magnesium (Mg²⁺), C to N ratio (C:N), basal respiration rate (RESP), and microbial biomass carbon (C_mic). The research indicated that tested tree species influenced water holding capacity (WHC), N_t, C:N, and RESP value. The highest N_t accumulation in soil was observed under N-fixing, but it did not transfer into higher organic carbon content under N-fixers. The soil under pine had a greater C:N ratio than the soil under birch, alder, and locust. The RESP rate was highest under birch. In terms of substrate type, RMS developed on Miocene clays exhibited higher carbon and macronutrient contents followed by ashes, whereas sands exhibited the lowest values of both physicochemical and microbial properties. The study suggested that both tree species and substrates affect microbial activities and physicochemical properties of RMS; however, the substrate effect is stronger. Full article

Peatlands have been irreversibly destroyed by draining and mining for horticulture, in the course of which tremendous amounts of greenhouse gasses were released into the atmosphere. To avoid this in the future, sustainable alternatives are urgently needed to substitute peat as growing media. An appropriate alternative could be biochar, because it has beneficial effects on nutrient availability and retention, water holding capacity, and organic matter stability. In this study, we compared three different commercially available biochar-containing growing media (Palaterra, Sonnenerde, Terra Magica) with three commercially available peat-based growing media (CompoSana, Dehner die leichte, Dehner mit Vorratsdünger), in a randomized greenhouse pot experiment. Pure sand was used as a control and, to test a potential amount effect, we mixed the used growing media with increasing amounts of pure sand (0, 25, 50, 75, and 100 volume % of individual growing media). The consecutive yields of several agronomically relevant cereals (barley, wheat, and maize) were measured in the mixtures mentioned previously. Additionally, the contents of biochar, amino sugar, and polycyclic aromatic hydrocarbons were measured in each pure growing media before and after the growth experiments. Only Sonnenerde exhibited an increased plant yield of 30–40% compared with peat-based growing media. The growing media exhibited no significant differences of chemical soil properties during the experiment. Only slight tendencies are recognizable towards higher fungal community in biochar- and peat-based growing media. A clear fungi contribution was observed in Palaterra, most probably due to the fact that fungi was a production ingredient. Surprisingly, peat-based growing media also contained about 30 g kg⁻¹ black carbon, a polycondensed aromatic carbon typical for biochar. Overall, our results indicated that biochar-containing growing media, especially Sonnenerde, is a potential alternative for peat-based growing media in horticulture and can enhance degraded soils. Full article

The roles of different tree species and their impacts are key in assessing the dynamics of soil restoration in afforested post-mining sites. The objective of this study was to compare the effect of Scots pine (Pinus sylvestris L.), which is native to Central Europe and commonly used in afforestation, to that of the non-native black pine (Pinus nigra Arn.) on the development of carbon pools and the chemical properties of reclaimed soils after sand exploitation. The study was carried out in 20- and 35-year-old stands, and the results were compared to undisturbed forest sites. Samples of the litter horizon and mineral soils (0–5 and 5–20 cm) were analyzed for pH, soil organic carbon (SOC), and total nitrogen (Nt). In addition, electrical conductivity (EC), sorption complex properties, water-soluble carbon, and hot-water-extractable carbon were determined from the mineral soil samples. Scots and black pine had a similar effect on the properties of the reclaimed soils. However, the soils under Scots pine were characterized by lower pH values in the litter and 0–5 cm horizons, higher EC in the 0–5 cm horizon, and higher C stocks in the litter horizon. Changes in the C stocks and chemical properties with afforestation years were limited to the uppermost soil horizons (litter and 0–5 cm). For both pine species, soils under the older stands were characterized by lower pH, higher EC, higher exchangeable acidity, higher cation-exchange capacity, lower base saturation, higher SOC and Nt contents, and more stable soil organic matter than soil under younger stands. After 35 years, about 20% and 27% of the C stocks in the reclaimed mine soils had been restored under black pine and Scots pine, respectively (compared to undisturbed soils). This difference between the pine species resulted from the higher C stocks in the litter horizons under Scots pine. Pedogenesis in post-mining sites after sand exploitation under pine species tended to result in more acidic and oligotrophic soils in relation to the undisturbed soils in adjacent forest ecosystems with pine. Full article

Mining activities for mineral resources over the years have resulted in major soil damage. Due the removal process of desired mineral materials, soil textures have been destroyed, various nutrient cycles have been disturbed, and microbial communities have been altered, affecting vegetation and leading to the destruction of wide areas of land in many countries. Therefore, soil restoration of abandoned mining lands became a very important part of sustainable development strategies and also prescribed by law in several countries. The main aims of this study were to develop an ecological land restoration strategy to the degraded lands due former kaolin, quartz sand, and iron mining located in Aghireșu and Căpușu Mare in Cluj County, in the Northwestern part of Transylvania from Romania and monitor soil quality changes over 40 years. To assess the effectiveness of soil reclamation of mine lands, 30 soil profiles were examined and 450 soil samples were collected from three depths (0–20 cm, 20–50 cm, and 50–80 cm) and subjected to physical and chemical analyses, and compared for their sustainable and beneficial use. All the proposed plant covers (natural grassland, pasture cover, black locust, Norway spruce, and scots pine) significantly improved the overall soil quality with the increasing years of reclamation following various patterns. Pasture cover most significantly enhanced the soil’s microbial activity, organic carbon, nitrogen, phosphorus, and potassium content followed by natural grassland. The results of this study show that considerable changes in soil quality was reached by revegetation of these abandoned mine lands restoring their ecological integrity and self-sustainability. Full article

Magnetite is a type of iron ore and a valuable commodity that occurs naturally in black sand beaches in the Philippines. However, black sand mining often takes place illegally and increases the likelihood and magnitude of geohazards, such as land subsidence, which augments the exposure of local communities to sea level rise and to typhoon-related threats. Detection of black sand mining activities traditionally relies on word of mouth, while measurement of their environmental effects requires on-the-ground geological surveys, which are precise, but costly and limited in scope. Here we show that systematic analysis of remote sensing data provides an objective, reliable, safe, and cost-effective way to monitor black sand mining activities and their impacts. First, we show that optical satellite data can be used to identify legal and illegal mining sites and characterize the direct effect of mining on the landscape. Second, we demonstrate that Interferometric Synthetic Aperture Radar (InSAR) can be used to evaluate the environmental impacts of black sand mining despite the small spatial extent of the activities. We detected a total of twenty black sand mining sites on Luzon Island and InSAR ALOS data reveal that out of the thirteen sites with coherence, nine experienced land subsidence at rates ranging from 1.5 to 5.7 cm/year during 2007–2011. The mean ground velocity map also highlights that the spatial extent of the subsiding areas is 10 to 100 times larger than the mining sites, likely associated with groundwater use or sediment redistribution. As a result of this subsidence, several coastal areas will be lowered to sea level elevation in a few decades and exposed to permanent flooding. This work demonstrates that remote sensing data are critical in monitoring the development of such activities and their environmental and societal impacts. Full article