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•Weathered coal ash landfills exhibit pH decrease and formation of secondary minerals.•High sulfur content in CCR impedes pedogenesis and limits plant growth.•The presence of ...montmorillonite accelerates pedogenesis.•Particle properties such as SSA and CEC change with pedogenesis in coal ash landfills.•13C NMR spectra point to the unburned coal particles as the main origin of organic matter.
Coal combustion has been one of the most dominant sources of energy for the last two centuries, generating tonnes of coal combustion residue (CCR). Rapid soil formation has been observed at old CCR disposal sites, altering the physiochemical and mineral properties of CCR, affecting contaminant release mechanisms and nutrient availability. Although ubiquitous, pedological properties of weathered CCR have been studied at only a small number of disposal sites. This study characterized two CCR landfills of similar age (∼50 years) using a range of parameters, including pH, total nitrogen and organic carbon content, major oxides (Al2O3, CaO, and SiO2), and macronutrients (Ca, K, Mg, P, and S), as well as textural and mineralogical data. In addition, specific surface area and cation exchange capacity were determined to assess particle properties, and 13C and 29Si NMR spectra were examined to characterize the organic matter and degree of polymerization of the coal ash glassy phase. Such comprehensive approach aimed to determine indicators of soil formation and to characterize the capacity of such landfills to retain water, nutrients, and contaminants. Both landfills displayed evidence of pedogenesis reflected in the pH decrease, formation of secondary minerals (such as ettringite, hydrotalcite, gypsum, and calcite), and changes in the C:N ratio. The Plaški landfill seems to have a better capacity to hold water, nutrients, and contaminants evident by higher clay content, CEC, and SSA values, possibly explaining why it developed more rapidly than Štrmac despite their similar age. The presence of montmorillonite in Plaški could be one of the main factors accelerating pedogenesis. 13C NMR spectra point to the unburned coal particles as the main origin of organic matter and 29Si NMR spectra showed higher depolymerization of a non-crystalline fraction in bare ash samples than in vegetated ash samples.
Being critical to achieving Sustainable Development Goals (SDGs) of the United Nations, strengthening understanding of the properties and processes of soil at national and regional scales is ...imperative. The necessity to realize SDGs by 2030 also inspires a greater sense of responsibility and care for soils. Sustainable management of soil health is important to achieving several SDGs. Pertinent SDGs intricately connected with soil health include SDG 1 (End Poverty), 2 (Zero Hunger), 3 (Good Health and Wellbeing), 5 (Gender Equality), 6 (Clean Water and Sanitation), 7 (Affordable and Clean Energy), 9 (Industry Innovation and Infrastructure), 11 (Sustainable Cities and Communities), 12 (Responsible Consumption and Production), 13 (Climate Action), and 15 (Life on Land). Some of these SDGs rely considerably on plant production and others depend on soil processes. Pertinent among soil processes are water movement, heat transfer, sorption and physical filtration, ion exchange, and biochemical and biophysical transformations. In terms of specific accomplishments, 130 countries have aligned with the Zero Hunger Challenge, the globally available fresh water has decreased to 71% of needs, Technosols (soils whose formation is influenced by anthropogenic based materials) are used in urban ecosystems, food wastes are composted, specific targets of Land Degradation Neutrality have been signed by several countries, and soil C sequestration targets are widely implemented through initiatives such as the 4 Per Thousand (4P1000) initiative, Platform on Climate Action in Americas (PLACA), Adapting African Agriculture (AAA), Living Soils of the Americas (LiSAM), etc. In addition, policy and regulatory frameworks being widely promoted by several U.N. agencies (e.g., U.N. SDGs,limiting global warming to 1.5°C or 2 °C) can be supported by innovations in soil science including forensic soil science, remote sensing and other innovations.
Soil health is becoming a central element of the research and innovation program of the EU, aiming to reach a 75% of healthy soils by 2030. In addition, the importance of soil health to human health and environmental issues is being widely promoted through educational books on soil science and secondary schools, as well as the revision of curricula. With continuous progress in movement into the digital world, transfer and communication of knowledge of the soil sciences can improve for the end users, policymakers, and the general public but additional efforts are needed. Soil science knowledge and research forms a significant contribution to specific aspects of food and nutritional security, human wellbeing, nature conservancy, and global peace and harmony. Achieving critical SDGs by 2030 can be facilitated by soil restoration and sustainable management.
•Soil restoration and management provide sustainable solutions to global challenges.•Soil management mitigates poverty, hunger, global warming, and land degradation.•Soil health is critical to plant, animal, human, environmental and planetary health.•Soil education is needed to increase understanding of soil's importance.•Soil education enhances humanity's connection to the land.
Coastal cities are major centers of economic activity, which at the same time has negative consequences for the environment. The present study aimed to determine the concentrations and sources of ...PTEs in the urban soils of Taganrog, as well as to assess the ecological and human health risks. A total of 47 urban and 5 background topsoils samples were analyzed by ICP-MS and ICP-AES. A significant excess of Cu, Zn, and Sb was noted in urban soils compared to the upper continental crust and average world-soil (1.7–2.9 times). Statistical analysis showed that the elements in soils were of geogenic, mixed and anthropogenic origin. According to the single pollution index (PI), the greatest danger of soil pollution was represented by anthropogenic elements, namely Cu, W, Pb, Zn, Cd, and Sn, the levels of which were increased in residential and industrial areas. The median contents of As, Mn, Cr, Sr, Mo, Sb, Cu, W, Pb, and Zn were 1.1–2.1 times higher, while Cd and Sn were 2.5 folds higher in the urban soils compared to the background ones. The total pollution index (ZC) showed that only 15% of the soils had high level of pollution, which is typical for the industrial areas. Overall ecological risks were negligible or low in 92% of soils, and were mainly due to elevated levels of Cu, Zn, As, and Pb. Non-carcinogenic risks to humans were mainly related to exposure to La and Pb. The hazard index (HI) values for all PTEs were less than ten, indicating that overall non-carcinogenic risk for adults and children was low-to-moderate and, moderate, respectively. The total carcinogenic risk (TCR) exceeded threshold and corresponded to low risk, with Pb, As, and Co being the most important contributors. Thus, the industrial activities of Taganrog is the main source of priority pollutants.
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•The abundance of Cu, Zn, and Sb in urban soils in Taganrog exceeds natural levels.•Anthropogenic PTEs represent the greatest danger of soil pollution within the city.•Metallurgical waste leads to very high total soil contamination by PTEs.•Low ecological risk was found due to pollution by Cu, Zn, As, and Pb.•Moderate non-carcinogenic and low carcinogenic risks have been established.
This paper examines the temporal dynamics of terrestrial mollusks of the Nikopol manganese ore basin technosols. The research was carried out at the Research Centre of the Dnipro Agrarian and ...Economic University in Pokrov (Ukraine). Sampling was carried out in 2012–2014 on four variants of artificial soil: formed on red-brown clays, on loess-like loams, on gray-green clays, and on humus-rich layer. The distribution of the number of individuals in a mollusk population was described by broken stick, Motomura, log-normal, Zipf, and Zipf-Mandelbrot models. It was shown that the series of models that best describe mollusk abundance distribution is specific for a particular species and technosols type and generally is invariant over time.
•After 42 years of reclamation, the humus horizon has developed from spoil material.•In humus horizon the physical properties have been improved.•In the parent material, the physical properties ...deteriorated.•Mineral fertilization had a significant indirect effect on the improvement of physical properties in humus horizon.
Opencast mining destroys soils that have formed over many thousands of years. Their place is taken by post-mining areas such as external and internal dumps with materials whose physical and chemical properties are unfavorable from the point of view of plant growth and development. In order to minimize the negative effects of opencast mining, reclamation is necessary. In this work, we examined the impact of 42-year agricultural reclamation, in which three variants of mineral fertilization (0NPK, 1NPK, and 2NPK) were applied in the cultivation of alfalfa with the addition of orchard grass on changes in physical properties of Technosols. After forty-two years of agricultural reclamation, there has clearly been a differentiation of post-mining material into genetic horizons that differ in physical properties. The surface part of Technosols was converted to a humus-enriched surface horizon (Ap), which consisted of two subhorizons: Ap1 and Ap2, differing in structure, color, and consistency. In the 1978–2020 period in Ap1 of fertilized soils, there was a decrease in bulk density (BD, 9.0–10.9%) and particle density (PD, 1.5%), but an increase in structural stability index (SI, 243–337%), soil porosity (SP, 15.5–19.2%), air-filled porosity (AFP, 10.8–11.7%), field capacity (FC, 49–21.6%), plant available water capacity (PAWC, 46.4–48.0%) and S-index (46.9–50%). In the Ap2 subhorizon, there was a similar trend of changes; however, BD (for 2NPK), FC (for 1NPK), and PAWC (for 1NPK and 2NPK) were not significant. BD (5.4–14.3%) increased in most horizons of parent material (Cd) between 1978 and 2020, and SP (10.9–29%), AFP (16. 2–73.9%), and S-index values (9.4–34.4%) decreased. On the other hand, PD, SI, FC, and PAWC values did not change significantly.
Cultivation o alfalfa with orchard grass in the 1978–2020 period significantly affected the profile variation in physical properties of Technosols, which was not observed when the field experiment was set up (1978). In the Ap horizon, DB and PD had significantly lower values, while SI, SP, AFP, FC, PAWC, and S had significantly higher values compared to parent materials (Cd). This is related to the indirect effect of soil organic carbon (SOC), which was beneficial to improving the surface horizon properties of developing Technosols. The diversity of physical properties of the 42-years old post-mining Technosols in the Ap was dependent on fertilization, especially in the Ap1 subhorizon. In fertilized Technosols, the BD and PD values were lower, and SP, DP, AFP, FC, PAWC, and S values were higher compared to unfertilized Technosols. Parent material (Cd) horizons after 42 years of reclamation had similar physical properties regardless of fertilization.
Phytoremediation through forestry may be an effective means for reducing the metal loading in lands reclaimed after surface-coal-mining in the UK. Planted with mixed woodland, the soil loading of 5 ...key metals (Zn, Cd, Mn, Pb and Cu) decreased, significantly and progressively, compared to soils left as grassland through a 14 year forestation chronosequence on land reclaimed from the former Varteg opencast coalmine, South Wales. Fourteen years after initial tree planting, soil metal loadings decreased by 52% for Cd (4.3 mg∙kg−1 per year), 48% for Cu (2.1 mg∙kg−1 per year), 47% for Zn (7.3 mg∙kg−1 per year), 44% for Pb. (7.1 mg∙kg−1 per year) and 35% for Mn (45 mg.kg-1 per year). Analysis of metal loadings in the leaves of Alnus glutinosa (L. Gaertn) (Common Alder) and Betula pendula (Roth) (Silver Birch) found both to be involved in metal uptake with birch taking up more Cd, Cu, Zn and Mn and Alder more Pb. Concentrations of Zn, Mn and Cd (Birch only) increased significantly in leaves from, but not in soils, under older plantings. Since different tree species take up metals at different rates, mixed plantings may be more effective in forest phytoremediation.
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•Isolates the effect of forestation in reducing soil metal loadings of five key metals.•14 year forestation chronosequence.•Foliar analysis provides a direct link between tree growth and reduced metal loadings in soils.•Mixed species plantings may be more effective in forest phytoremediation.•Decontamination of former surface-coal-mine land in Wales
Recultivation of disturbed lands is very important task of science and practice at large territories of mining in Siberia as in other regions of Russia and other countries. Condition of physical ...properties of new-formed soils technozems (Technosols) is one of key questions for future state and usage of these lands. Changes of technozem's physical properties over time as part of land restoration and reclamation at Nazarovsky brown coal mine wastes (Eastern Siberia) were studied at one, three, ten and twenty years after the beginning of reclamation. Technozems here are artificially formed soil-like formations, which were made by the method of filling a material of fertile soil layer (fertile soil material or FSM) on the leveled surface of technogenic deposits. In the process of keeping of FSM and mechanical formation of technozems, there was a marked deterioration of the physical state of the FSM. In order to restore physical properties of FSM, perennial herbs were sown on recultivated areas. Studies of physical properties at different age sites have shown that at the meliorative stage they are gradually restored by climatic, biological and pedogenic factors. Exposure to perennial herbs contributes to soil structure formation and reduction of compounding density. In case of prolonged (10–20 years) meliorative action physical properties are restored to norm of soils which are widespread in this geographical zone. However, the sharp interface between FSM and technogenic material remains, which can have a negative impact on the water regime of recultivated soils. In order to accelerate formation of optimal physical conditions in technozems it is necessary to carry out deep, irrevocable loosening, which contributes to reduction of density of both bulk layer and underlying technogenic rock. Some physical properties (bulk density, porosity) were gradually improving over time reaching Haplic Chernozems levels at the reference site.
•Recultivation of disturbed land by filling of fertile soil material forms Technosols.•The density of fertile soil material in Technosols is dynamic and varies intensively.•Long-term planting of perennial herbs contributes to restoration of soil properties.•Deep loosening helps to reduce density of soil layer and underlying man-made rock.
Post-mining land reclamation of Athabasca Oil Sands (AB, Canada) involves the reconstruction of soil profiles able to support a mosaic of boreal forest communities. However, the use of ...coarse-textured reclamation materials to recreate forest ecosystems represents a challenge in terms of soil water and nutrient availability. This work aimed to quantify nutrient leaching in reclaimed coarse-textured soils constructed with two coversoils (peat mineral mix and forest floor mineral mix) underlain by mineral materials, including a blended B/C subsoil reclamation material, lean oil sand overburden substrate, and tailing sand. Water retention and conductivity curves were estimated for each material, and their retention capacity for inorganic N and P was measured in sorption isotherm experiments. The redistribution of water, inorganic N and P five days after an intense rain event was evaluated in six different reclaimed soil profiles using a laboratory-controlled leaching experiment in 1.2-m deep columns. The redistribution of fertilizer nutrients was also measured following the addition of 15N-labelled ammonium and phosphate over the top 10 cm of the columns. In addition, a 25-day incubation experiment with the two coversoils enabled us to estimate the timing of N immobilization and nitrification processes. Our results show that, depending on the combination of materials used for land reclamation, the soil profiles may provide equal or higher amounts of inorganic N and P in the rooting zone compared to natural, coarse-textured soils of the region. Following the simulated intense rainfall, the peat-mineral mix was able to retain 44% of its initial inorganic N within the top 20 cm of the reclaimed soil profiles, while 84% of the inorganic N present in the forest floor mineral mix was leached down. Compared to the movement of water, the leaching of N down the soil profiles was slower and partly restricted by the presence of lean oil sand, and to a lesser degree tailing sand. Most of the introduced fertilizer-N remained in the first 20 cm of the soil profiles under the form of nitrate, although the incubation experiment suggested that nitrification only occurred after the simulated rainfall event. Based on our experimental data and on additional simulations of water and nutrient transport, we conclude that nutrient leaching in reclaimed soils can be significant if specific materials such as forest floor mineral material and coarse-textured subsoil are combined and when an intense rainfall occurs at a period coinciding with a high concentration of nitrate-N in the topsoil.
•The stock of nutrients was comparable between reclaimed and natural soils.•N leaching depended on the design of soil cover and on the underlying substrate.•The downward movement of N was slower than the movement of water.•Fertilizer-N remained in the top 20 cm after an intense rainfall.
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