Floods and wildfires are two extreme environmental events with significant yet different impacts on soil health and on two particularly important soil pollutants, heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs), which are directly associated with ishytoxic properties and their ability to enter the food chain. The present study includes a methodological approach that was based on a literature review of published studies conducted worldwide regarding these two phenomena. The main forms of both pollutants, their possible sources and inevitable deposition onto the soil surface, along with their behavior–transport–mobility, and their residence time in soil were investigated. Furthermore, the changes that both HMs and PAHs induce in the physicochemical properties of post-flood and post-fire soils (in soil pH, Cation Exchange Capacity (CEC), organic matter content, porosity, mineralogical alterations, etc.), are investigated after a literature review of various case studies. Wildfires, in contrast to floods, can more easily remove large quantities of heavy metals into the soil ecosystem, most likely due to the intense erosion they cause. At the same time, floods appear to significantly burden soils with PAHs. In wildfires, the largest mean increases were observed for Mn (386%), Zn (300%), and Cu (202%). In floods, Pb showed the highest mean increase (534%), with Cd also rising substantially (236%). Regarding total PAHs, mean post-event concentrations reached 482.3 μg/kg after wildfires, compared to 4384 μg/kg after floods. Changes in the structure and chemical composition of flooded and burned soils may also affect the mobility and bioavailability of the pollutants under study. Overall, these two phenomena significantly alter soil quality, affecting both ecological processes and potential health impacts.

Heavy metal contamination of soils represents a persistent environmental challenge, for which in situ immobilization has emerged as a cost-effective and technically viable alternative to conventional invasive remediation technologies. This review comparatively evaluates three distinct categories of soil amendments—biochar, zeolite and attapulgite—within a unified analytical framework integrating extractable fractions (TCLP, DTPA, and CaCl₂) and geochemical fractionation approaches (BCR and Tessier). The novelty of this study lies in the systematic assessment of the dominant immobilization mechanisms associated with each amendment in relation to soil properties and the chemical speciation of the target metal, as well as in distinguishing between an apparent reduction in metal extractability and a genuine shift toward more stable geochemical fractions. The findings identify ion exchange as the primary immobilization mechanism in zeolites (NaA zeolite, 1–5% w/w, 96% reduction in TCLP-extractable Pb and 91% reduction in TCLP-extractable Cd), the synergistic action of adsorption, complexation, and precipitation in biochar systems (manure-derived biochar, 0–5% w/w, 97.4% reduction in the exchangeable Pb fraction according to the Tessier scheme), and the critical role of surface modification in attapulgite-based amendments (C-ATP, 4% w/w, 95.1% and 74.3% reductions in TCLP-extractable Pb and Cd, respectively). Because these efficiencies were obtained using different extraction protocols, they are not directly comparable. At the same time, cases of adverse responses were identified, including increased As extractability following the application of phosphate-modified biochar and the redistribution of Pb and Cd after amendment with natural zeolite in industrially contaminated soil. These observations highlight that amendment performance is not an intrinsic property of the material itself, but rather the outcome of specific geochemical interactions occurring within the soil system. Increased soil pH emerged as the principal common factor promoting metal stabilization across all amendment categories, whereas substantial variability in amendment dosage, incubation period, and analytical methodology limited direct quantitative comparisons among studies. Consequently, the selection of an appropriate soil amendment should be based on the integrated evaluation of soil physicochemical properties, contaminant speciation, and the intended scale of application, supported by long-term monitoring under field conditions.

The present study investigates the presence, sources, and impacts of microplastics (MPs) in different soil types, including agricultural, urban, and forest areas, through a synthesis of results of published scientific papers. MPs originate from a variety of human activities, such as the widespread use of plastic mulch in agriculture and the application of organic fertilizers and treated sewage sludge, as well as from vehicle tire wear, industrial processes, and the gradual degradation of plastic products in the environment. In urban soils, the main sources of MPs are related to road traffic, industrial activity, and landfills, while in forest soils, concentrations are generally lower. However, MPs in forest areas are thought to be carried there by the air, by runoff, or from nearby areas with human activity. Available data show that larger MP particles tend to remain in the surface layers of the soil, while smaller particles can penetrate deeper soil layers, increasing their bioavailability and the likelihood of interaction with microorganisms and plant root systems. In terms of their chemical composition, polyethylene (PE) and polypropylene (PP) polymers dominate in agricultural soils, which is directly linked to agricultural practices, while polystyrene (PS) and polyvinyl chloride (PVC) are more frequently detected in urban soils. The morphological types of MPs include fragments, fibers, and films, while their color characteristics provide clues to possible sources of origin, such as plastic ground covers, tire wear, and packaging materials. Overall, the study’s results underscore the growing environmental significance of MP soil pollution and highlight the need for more effective management and recycling of plastic materials, as well as for further interdisciplinary research aimed at understanding the mechanisms of transport, accumulation, and long-term ecological effects of microplastics in terrestrial ecosystems.

Tobacco (Nicotiana tabacum) cultivation generates millions of tons of stalk waste annually. This review explores the potential of tobacco stalks as a renewable resource, emphasizing sustainable applications within a circular economy framework, and highlights the key innovative advances. Composting and biochar production from tobacco residues can substantially enhance soil structure, nutrient availability, microbial activity, and heavy metal immobilization, supporting soil restoration and climate-smart agriculture. With 30–36% cellulose and moderate lignin contents, stalks can be converted into bioenergy, biogas, compost, and biopesticides and enable the production of cellulose derivatives. Despite promising results, challenges remain in nicotine detoxification, process optimization, and industrial scalability. Future research should focus on integrated technologies and life-cycle assessments to fully realize the environmental and economic benefits of tobacco waste valorization.

Soil salinization affects more than 424 million hectares of topsoil worldwide and is associated with yield losses of 18–43% in drylands, yet its long-term dynamics have rarely been compared across regions on a common basis. This work synthesizes nine case studies from a systematic, PRISMA-guided search, selected purposively to maximize variation in climate, scale and method. ECe (dS/m) and total salt content (g/kg) have no general conversion, so the eight ECe-based studies are compared class by class using their own figures; the single g/kg study contributes direction only, and no values are pooled. The largest transfers occur between the intermediate and higher classes, while the non-saline class changes little in most settings; intensification of already salt-affected land therefore predominates over conversion of new land, though the latter also occurs (Bachu County). The drivers reported by the source studies are irrigation expansion, inadequate drainage, and shallow saline groundwater, with rising evaporative demand and reduced leaching as amplifiers; since no study partitions the change between climatic and management causes, this ordering is descriptive, not a causal attribution. The synthesis is hypothesis-generating; its main product is a direction-of-change summary table separating observed trends from projections.

Heavy metal contamination poses a major threat to soil quality and agricultural sustainability, particularly in Mediterranean regions affected by both anthropogenic activities and naturally metal-rich parent materials. This study evaluated the potential of iron oxide nanomaterials (Fe₃O₄) as a soil amendment for reducing heavy metal mobility in three agricultural soils from Western Macedonia, Greece, representing contamination from (i) lignite-fired power plant emissions, (ii) mining activities, and (iii) geogenic enrichment associated with ultramafic (ophiolitic) parent material. Fe₃O₄ nanomaterials were applied at rates of 0.5 and 1.0% (w/w), followed by a 45-day laboratory incubation alongside untreated controls. The application of Fe₃O₄ nanomaterials modified selected soil physicochemical properties, with the strongest response observed in the acidic mining soil, where soil pH increased from 5.80 ± 0.08 to 6.02 ± 0.07 and cation exchange capacity increased by approximately 10%, indicating more favorable conditions for metal retention. Changes in metal mobility and fractionation, assessed using calcium chloride (CaCl₂) and diethylenetriaminepentaacetic acid (DTPA) extractions and the Community Bureau of Reference (BCR) sequential extraction procedure, showed a marked reduction in the most readily extractable metal fractions, although the magnitude of the response varied according to soil properties, initial metal mobility, and geochemical distribution. The strongest immobilization response was observed in the mining soil, where the 1.0% rate reduced CaCl₂-extractable Cu, Zn, Cd and Pb by approximately 50, 40, 47 and 68% relative to the untreated control, whereas the changes in the geogenic soil were small. Metals lost from the exchangeable and acid-soluble fraction were recovered mainly in the reducible fraction, indicating redistribution among soil fractions rather than removal from the soil. Overall, Fe₃O₄ nanomaterials effectively immobilized potentially toxic metals under the conditions examined, although their efficiency depended on soil properties, contamination source, initial metal mobility, and geochemical distribution. These findings indicate that remediation performance cannot be predicted solely from pseudo-total metal concentrations and highlight the need to adapt Fe₃O₄ application strategies to site-specific soil characteristics and contaminant fractionation. As these results derive from a 45-day laboratory incubation, longer-term and field-scale evaluation is required before wider agricultural application can be recommended.