Soil organic carbon (SOC) fractions are important input parameters for process-based models, while the distribution and influencing factors of SOC fractions in alpine permafrost regions remain largely unknown. Here we collected 150 soil samples from 50 sites for surface 30 cm depth in permafrost regions on the Qinghai-Tibet Plateau (QTP). We analyzed SOC content, particulate organic carbon (POC) and mineral-associated organic carbon (MAOC), and further investigated their relationship with environmental factors using regression and random forest models. The results showed that the POC/SOC ratios were significantly lower in alpine steppe (5

The levels of natural radionuclides (40K, 232Th, 226Ra) and 137Cs in the soil samples from three East Antarctic zones (near the Progress, Molodyozhnaya and Bunger Oasis field stations) were measured using background gamma spectrometry. The measured activity concentrations ranged from 513 to 1134 Bq/kg for 40K, 1.1 to 5.5 Bq/kg for 137Cs, 35 to 238 Bq/kg for 232Th, and 7.5 to 59 Bq/kg for 226Ra. Correlation analysis revealed a strong positive correlation between 226Ra and 232Th. To evaluate the radiological impact on station personnel, key hazard indices - including radium equivalent activity, external dose rates, annual effective dose, and excess lifetime cancer risk - were computed. At some locations, particularly near Progress Station the values of internal and external risk indices, exceed 1.0, indicating a possible radiological risk to human health. At all sites, except Molodyozhnaya Station, the absorbed dose rates exceeded the global reference value of 57 nGy/h. Although the mean activity concentrations of the radionuclides are consistent with, or lower than, those reported for other Antarctic regions, they result in slightly elevated terrestrial gamma dose rates compared to global soil averages. However, this increase is negligible in the context of total radiation exposure.

Resolving the global phosphorus (P) paradox-ensuring food production for growing population while preventing geological resource depletion and aquatic degradation-demands innovative strategies that move beyond simply reducing environmental discharges. Current solutions often overlook the synergistic benefits of source control and circular economy enhancement, leading to fragmented sustainability assessments. Here we investigate China's Yangtze River Economic Belt (YREB), a global socioeconomic nucleus exhibiting archetypal P imbalances. By integrating seven decades (1950-2020) of substance flow analysis with a novel systemwide evaluation module, we systematically quantified the sustainability potential of 15 interventions across production, processing, consumption, and waste disposal stages. Our finding revealed peak-plateau P flow dynamics characterized by a critical transition from organic nutrient recycling to inorganic P rock dependency (11.5 Mt/ yr). This shift has accelerated geological reserve depletion to less than 30 years while driving annual environmental discharges exceeding 2.65 Mt, particularly in socioeconomic hubs intersecting major hydrological networks. Forward-looking scenarios for 2050 indicate that comprehensive waste valorization (S4) could more than double regional P reserve longevity (+119.8%), while synergistic agricultural reform (S2) might halve peak environmental losses. This systemic mineral provisioning-water security framework provides a transferable policy design paradigm for P-vulnerable basins worldwide that face similar sustainability paradoxes.

This study investigates soil organic matter (SOM) mineralization rates and ecotoxicological state of major soil types in the Yamal region of West Siberia, Russia. Soil samples were collected from three sites: Lower Ob Basin, Rai-Iz mountain massif (Polar Urals), and southern Yamal Peninsula. SOM mineralization was assessed through 90-day incubation experiments at 10 and 25 degrees C, determining potentially mineralizable organic carbon (PMC) and basal respiration rates. Ecotoxicological assessment included analyses of heavy metals (Sr, Pb, Zn, Co, Ni, Cr, V, As, MnO) and the calculation of the total soil pollution index (Zc). The content of PMC varied from 279.50 mg/kg to 37,254.15 mg/kg, constituting 11.59%-2.74% of total soil organic carbon at 25 degrees C. Maximum mineralization occurred in upper organogenic horizons of Histosols and Podzols, while mineral and cryoturbated horizons showed lower rates. Temperature dependence was evident, with higher mineralization rates at 25 degrees C in most samples, though some mineral horizons showed the opposite pattern. Regarding ecotoxicological state, 32 of 47 soil samples showed low (acceptable) contamination levels (Zc < 16), 13 samples demonstrated moderate (moderately hazardous) levels, and only 2 samples showed high (hazardous) contamination. Priority pollutants were lead (Pb), vanadium (V), and cobalt (Co), with spatial patterns indicating vehicle emissions as a major contamination source near transport arteries. The radial differentiation coefficient revealed distinct redistribution patterns of elements across soil profiles. Overall, the soil cover of northern Western Siberia exhibits generally low anthropogenic contamination, though moderate to high contamination levels were found in areas associated with oil and gas production facilities and roadside territories. The integrative analysis suggests that areas of high anthropogenic pressure coincide with significant carbon stocks, warranting further investigation into the interplay between pollution and carbon cycle feedbacks.

Understanding historical phosphorus (P) cycling in crop production is essential for sustainable P management and water quality protection. This study adopts a comprehensive perspective of the crop production process, focusing on Jiangxi Province, an intensively farmed region in China. A bottom-up, multi-year dynamic phosphorus substance flow analysis (P-SFA) model was developed considering regional social diversity and P flow complexity. The P cycle in Jiangxi shifted from a natural-dominated steady state to a human-driven unidirectional system, with major changes occurring between 1978 and 2015. Agricultural intensification and livestock expansion have continuously increased P flows in the region. Total P input rose from 5.84 × 104 t in 1950 to 2.13 × 105 t in 2020, representing an almost fourfold increase. Since 1950, chemical fertilizers became the largest P source, reaching 1.25 × 105 t (58.86% of total) in 2020. Interpretability-based machine learning (ML) model quantified the influence of P flow drivers. SHAP (Shapley Additive Explanations) analysis confirmed that agriculture accounts for over 75% of P flow intensity, highlighting key socio-economic factors. This nonlinear identification method offers a new perspective for SFA. The SFA–ML model improves understanding of P flows and their role in watershed P cycling.

Founded in 1703, St. Petersburg was the capital of the Russian Empire. Its historic center and associated monuments are inscribed as a UNESCO World Heritage Site. Its components are classified as cultural rather than natural or mixed. We hypothesized that a part of them has an additional ecotourism value. We carried out field observations along with a review of the literature. Our results confirmed the hypothesis: many of these sites retain important elements of biodiversity that can be used for environmental education. Large congregations of birds can be observed in close proximity to Heritage monuments. Wintering bats occupy the interiors of historic fortifications, and in summer, concentrations of feeding bats can be found nearby. Seal haul-out sites have been documented on small islands near the city. The ecotourism and nature-conservation value of these Heritage landscapes is usually linked to the original logic of their selection. The best locations were chosen for palace construction—dry, scenic areas with fertile soils suitable for park creation. Proximity to bodies of water was equally important, both for aesthetic reasons and for sanitation. These same qualities also make such areas highly favorable for biodiversity. Even after centuries of development, many natural features have persisted.

Global anthropogenic phosphorus (P) cycle changes require active management with differentiated sustainability strategies across countries. This study developed a universal framework that integrates the comprehensive P flow process with sustainability scenarios to assess global anthropogenic P flow patterns and explore future sustainability pathways and potential. The results indicated that the global P flow imbalance intensified from 1961 to 2022, with over 80% attributed to croplands. Crucially, global trade serves as a significant driving force, redistributing P resources and reinforcing the global complexity of P-pollution footprints, driven by 35 key countries. Our model projects that by 2050, individual measures like reducing fertilizer applications, improving feed conversion efficiency, and recycling organic fertilizers could save 50% of P and reduce P losses by 39%. Crop-livestock integration significantly improved P use efficiency, potentially extending the global phosphate rock extraction period by 400 ± 87 y (mean ± SD). However, due to the low baseline P use efficiency in cropping systems, P recovery from waste in developing countries remains limited, necessitating additional measures alongside the above high-leverage measures. These findings underscore the indispensable role of human consumption and the transformative potential of dietary shifts, which are essential given that no country can achieve significant P sustainability gains solely by reducing food waste or processing losses. Coordinated supply and demand-side measures linking cropping, livestock, and consumption offer key strategies and benefits for systematically and differentially advancing P sustainability at both global and national levels.

Soil micro- and nanoplastic contamination is escalating globally, yet its potential to interfere with routine agrochemical analyses remains poorly quantified. Standard operating procedures (SOPs) were calibrated for natural soil matrices and may not account for synthetic, carbon-rich polymers. This controlled model study quantified the analytical sensitivity of FAO/GLOSOLAN/ISO standard procedures to polystyrene nanoparticle (50 nm) contamination across a 0–0.5% (w/w) gradient in a Luvic Chernozem. Key parameters—pH, soil carbon, total nitrogen (TN), cation exchange capacity (CEC), and clay fraction—were measured following standardized protocols. The Walkley–Black method exhibited a strong dose-dependent increase in measured SOC (r = 0.93), reflecting systematic overestimation due to dichromate co-oxidation of polymer matrix, likely facilitated by exothermic heating above polystyrene’s glass transition temperature. The Dumas method showed moderate correlation (r = 0.59) but higher replicate variability driven by small aliquot size and heterogeneous nanoparticle distribution. The pH measurements displayed non-linear responses and elevated variability at low doses, whereas TN, CEC, and clay content remained statistically stable. These findings demonstrate that nanoplastic contamination can introduce significant analytical artifacts in oxidation-based SOC determinations, potentially leading to misinterpretation of soil carbon trends. Given the single-soil, single-polymer design, results represent a system-specific proof of analytical vulnerability rather than a universally quantified bias. Laboratories analyzing potentially contaminated soils should exercise caution with wet-oxidation SOC data, and broader SOP revisions must await multi-soil, multi-polymer validation campaigns.

Humic acids (HAs) represent structurally heterogeneous supramolecular systems whose characterization by CP/MAS 13C NMR spectroscopy strongly depends on experimental conditions. Among these, contact time is one of the most important parameters controlling the efficiency of polarization transfer and the relative contribution of individual carbon groups. The aim of this study was to evaluate the influence of contact time on the apparent CP/MAS 13C NMR signal distribution of HAs isolated from different horizons of a permafrost peat soil (Hemic Folic Cryic Histosol) and to characterize their cross-polarization dynamics using kinetic modeling. A series of CP/MAS 13C NMR spectra was acquired at contact times ranging from 0.01 to 10 ms. Signal intensities of major structural groups were analyzed using both the classical three-parameter model and an extended four-parameter model of cross-polarization dynamics. The results demonstrated pronounced contact-time-dependent variations in the apparent CP/MAS signal distribution among alkyl, aryl, and carboxyl/amide structural domains. Short contact times preferentially enhanced proton-rich aliphatic and carbohydrate structures, whereas longer contact times increased the relative contribution of aromatic and carboxyl/amide fragments. The extended model provided a better fit for selected structurally heterogeneous spectral regions, particularly aromatic and heteroatom-containing domains, whereas the classical model adequately described the relatively homogeneous aliphatic regions. The fitted CP-dynamic parameters provided effective comparative descriptors of the investigated HAs under the experimental conditions employed and demonstrated consistent depth-dependent differences within the investigated peat profile. These depth-dependent differences may reflect changes associated with peat accumulation and long-term cryogenic preservation; however, this interpretation requires confirmation using independently replicated peat profiles.

Changes in soil organic carbon (SOC), total nitrogen (TN), and metal elements (MEs) in permafrost regions may trigger climate feedback and human health risks under a warming climate. However, vertical distribution patterns of SOC, TN, and MEs in the active layer and deep permafrost remain unclear. Here, we collected three 0-600 cm soil cores from the central Qinghai-Tibet Plateau (QTP). The results showed that SOC and TN contents were significantly higher in the active layer than in the permafrost (p < 0.05), and MEs exhibited considerable fluctuations between the two layers. In the active layer, soil pH was the strongest predictor for SOC, TN, and MEs (p < 0.001), whereas in the permafrost, an unexpectedly strong coupling among SOC, TN, and MEs was observed (p < 0.001). Furthermore, most MEs posed a relatively low ecological risk, whereas cadmium (Cd) exhibited a moderate ecological risk at the threshold level. These findings provide novel insights for further exploring the deep biogeochemical processes of the permafrost ecosystem.

Glacial and periglacial environments in alpine regions are increasingly threatened by anthropogenic activities and climate change, yet the supraglacial-periglacial redistribution of trace elements and role of nature reserves in these fragile ecosystems remains understudied. This research evaluates contamination levels in cryoconites and soils of two adjacent gorges in the Central Caucasus: the strictly protected Tsey Gorge and the tourism-intensive Skazka Gorge. Trace elements (Cu, Zn, Ni, Pb, Cd), basic physicochemical properties and pollution indices were analyzed. Zn was the most abundant element in both gorges (maximum of 79.00 mg & centerdot;kg-1), attributed to natural geological background and legacy Pb-Zn mining. Conversely, Cu (max. 23.30 mg & centerdot;kg-1) and Ni (maximum of 34.15 mg & centerdot;kg-1) contamination in Skazka Gorge correlated with tourism infrastructure and related processes. Cryoconites acted as transient reservoirs, with meltwater facilitating the downstream transfer of trace elements to soils, evidenced by higher contamination in periglacial zone. Pollution indices classified Tsey as "unpolluted" and Skazka as "slightly polluted," with moderate ecological risks in soils. The study demonstrates that protected areas and promotion of "eco-tourism" effectively reduced tourism-driven contamination, while geogenic and mining influences continue to affect the environmental quality of the studied alpine zone. (c) 2026 Beijing Normal University. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Agricultural land abandonment is widespread in high-latitude regions, yet its effects on soil microbial communities in permafrost ecosystems remain insufficiently understood. In this study, we used a 0–25 year chronosequence of abandoned soils in the Yamalo–Nenets Autonomous Okrug to analyze the succession of soil microbial communities and compared them with mature reference Podzols. Soil physicochemical properties, microbial community composition, and potential functional changes were systematically assessed using 16S rRNA gene sequencing, multivariate statistical analyses, and functional prediction. The results showed that, in mature soils, SOC was the key factor driving microbial community variation, whereas in agricultural and abandoned soils, available nutrients were the main factors influencing microbial community structure. The abandonment process also constrained soil microbial mineralization. The dominant microbial phyla mainly included Proteobacteria, Acidobacteriota, Verrucomicrobiota, Bacteroidota, and Actinobacteriota, while the relative abundances of other taxa differed markedly among land-use stages. Agricultural soils were dominated by copiotrophic microbial groups, whereas microbial communities in abandoned soils gradually shifted toward oligotrophic groups with increasing recovery time, and some taxa associated with the degradation of complex carbon substrates also increased in abundance. Functional analysis further indicated that carbon and phosphorus cycling functions in soil microbial communities exhibited a certain degree of functional redundancy, whereas nitrogen-cycling functions depended more strongly on specific microbial taxa. Land abandonment promoted an increase in the abundance of genes related to microbial carbon metabolism in soil. However, even after 25 years of abandonment, microbial community composition and functional potential had not fully recovered to the level of mature reference Podzols, indicating that agricultural disturbance exerts long-term legacy effects on soil microbiomes in permafrost-affected regions.

This pilot study focuses on the non-invasive determination of microplastic (MPs) and anthropogenic particle contamination in Northern Fur seals (Callorhinus ursinus) in the Sea of Okhotsk, Russia, based on the analysis of six scat samples. The work included a comparative review of MPs extraction methods aimed at optimizing the digestion protocol to minimize particle loss. Potential contaminants were isolated from samples collected on Tyuleny Island and characterized by type, color, size, and composition. Spectral analysis of the material composition using Raman spectroscopy revealed the presence of an insignificant number of plastic microfibers, so at this stage it is only possible to conclude that they were not unequivocally detected. However, the overall load of anthropogenic particles, represented mainly by cellulose fibers with synthetic dyes, was substantially higher. The majority of colored fibers and fragments contain synthetic dyes, confirming their anthropogenic origin. The obtained results highlight the need for further research with an expanded sample size and the mandatory application of chemical methods for material composition analysis.

Supraglacial sediments play a pivotal role in nutrient redistribution within alpine ecosystems, yet their biogeochemical dynamics in the context of glacier retreat remain understudied. This study investigates the geochemical and microbial characteristics of cryoconites, supraglacial sediments, and periglacial soils across the Tsey and Skazka Glaciers in the Central Caucasus, Russia. Samples were taken in August 2023 in order to estimate biogeochemical flows during the ablation period after the most active spring/summer translocation. We analyzed total organic carbon (TOC), dissolved organic carbon (DOC), microbial respiration, and available nutrients (N, P, K) to assess their roles in post-glacial soil formation. Results revealed significantly higher TOC in Skazka Glacier sediments (max. 2.27 %) compared to Tsey Glacier (max. 0.91 %), attributed to anthropogenic activities (e.g., tourism, construction) and cryoconite carbon accumulation. DOC levels were uniformly low in glacial sediments but elevated in periglacial soils (up to 82.27 mg center dot kg- 1), reflecting active meltwater translocation of labile carbon. Phosphorus dominated supraglacial zones, linked to mineral weathering, while nitrogen and potassium exhibited stronger retention in organic-rich topsoils. Microbial activity, though limited on glaciers, surged in soils (up to 48.12 mg CO2 center dot 100 g- 1 center dot day- 1), driven by inputs of downstream-translocated nutrients. These findings underline the dual role of supraglacial sediments as nutrient reservoirs and transmitters and suggest that ongoing glacier retreat, combined with increasing anthropogenic pressures, modifies regional nutrient cycling dynamics, potentially impacting downstream water quality by nutrients enrichment and promote alpine soils development.

The soils of the Lena River Delta contain significant reserves of soil organic matter, and as a result of riverine erosion and permafrost degradation, the coastal zone is undergoing rapid transformation, releasing substantial amounts of buried carbon from organic-rich permafrost soils and Ice Complex deposits. To investigate the influence of fluvial processes and cryogenesis on the physical stabilization of SOM, we analyzed the microstructure of Cryosols (15 soil samples) and Ice Complex (4 deposit samples) using polarization microscopy (Leica DM750P) and ImageJ software (National Institute of Health, USA). The study revealed the specifics of soil formation in the Lena River Delta, as well as the features of organic matter release from the frozen state. Thin sections of soils subjected to periodic flooding and long-term freeze/thaw cycles were examined, alongside organomineral deposits exposed by degradation of the Ice Complex. Results indicate that soils affected by prolonged cryogenic processes (long-term freezing and thawing cycles) exhibit the highest degree of soil organic matter physical stabilization, likely due to microaggregate formation. In contrast, freshly thawed Ice Complex deposits show lower aggregation stability, suggesting a potential vulnerability to biodegradation upon release from permafrost. These findings highlight the critical role of cryogenic and fluvial dynamics in regulating Arctic carbon cycling under climate change.

Reedbeds can have significant conservation value because birds, fish, and other animals concentrate there. Such areas exist in the Gulf of Finland near the mouth of the Neva River, while they have been lost in the river's mouth due to urbanization (the expansion of St. Petersburg city). Now there are seven reedbed areas, covering a total of 14.5 square kilometers. These wetlands stimulated the creation of protected wildlife areas nearby. The distribution of reedbeds may seem random, but we hypothesized that their location is influenced by wastewater. Our hypothesis was confirmed based on the data of sewage treatment facilities and historical maps (1855, 1913 and 1941). It turned out that local protected areas follow patterns of pollution. This situation suggests that, in urbanized areas, it is possible to predict and model the location of reedbeds. Conversely, observing the presence of reedbeds could serve as an indicator of hidden polluted effluents, prompting further research.

Investigating radionuclide distributions in Arctic soils is essential for evaluating environmental and health risks in the region. Low-background gamma spectrometry was used to determine the activity concentrations of 40K, 226Ra, 232Th, and 137Cs in nine soil samples collected in the Yamal-Nenets Autonomous Okrug, Russia. The mean activity concentrations of radionuclides were: 350 ± 151 Bq·kg−1 for 40K, 2.2 ± 1.1 Bq·kg−1 for 137Cs, 18.2 ± 9.4 Bq·kg−1 for 232Th, and 16.6 ± 8.0 Bq·kg−1 for 226Ra. Correlation analysis revealed a strong positive relationship between the natural radionuclides (r = 0.85–1.00), confirming a common geogenic sources. The calculated radiological hazard indices—including Raeq, Hex, outdoor absorbed gamma dose rate, annual effective dose, and lifetime cancer risk—were all below internationally recommended reference levels, indicating that the investigated soils pose no significant radiological risk to the public.

Soil sampling and mapping of trace elements are challenging in Arctic regions. However, understanding the spatial distribution of them is crucial for effective environmental management and conservation efforts. Validating such digital maps is also a key consideration, especially in data-constrained conditions. In this study, we first evaluated the feasibility of digital soil mapping methods for spatial modeling of trace and heavy metals in the Russian Arctic with limited soil data. The random forest method was used to predict topsoil concentrations of As, Cd, Cr, Hg, and Ni, in combination with environmental covariates, including climate, relief, vegetation, geology, geographic position, anthropogenic impact, soil properties, and soil class maps. We used a clustered legacy dataset and tested map accuracy with spatial and nonspatial cross-validation (CV) techniques. We also estimated the uncertainty of the predictions and the area of applicability (AOA). We found that spatial and nonspatial CV resulted in different model performances, where conventional CV methods showed better performance. The mountainous area was beyond the AOA of all predictive models. Soil and climate variables were key predictors in the RF models. Despite the challenges of modeling trace elements in this study with sparse data, future efforts should prioritize expanded sampling in underrepresented environments, especially with distinct soil-forming factors, and multistage validation strategies tailored for clustered datasets. The presented mapping can be a starting point for regional and national initiatives to map trace elements and metals in northern regions.

The presence of plastic marine litter (ML) and its associated negative environmental impacts have been documented in all existing parts of the marine and coastal environment, including protected areas (PAs). The aim of this study is to identify gaps in existing research related to the lack of standardization of methods and scarcity of detailed information on the characteristics of ML found. This systematic review provides current information on the methods and results of studies focused on the problem of ML and microplastic (MP) pollution on the coastlines of PAs. This study was conducted in accordance with the PRISMA 2020 statement. It is based on 28 peer-reviewed publications from four online databases and search platforms: ScienceDirect, PubMed, MDPI and Google Scholar, published between 2021 and 2025. The presence of ML was detected in all 28 studies (100%), confirming the relevance of the problem along the coastlines of PAs, even those far from industrial centers. The reported densities, however, ranged from a few fragments of litter to several thousand items. Plastic was the most common material of ML among all the peer-reviewed publications analyzed. Most of the studies showed that polyethylene (PE) fragments were the dominant type of microplastic (MP) found in coastal environments of PAs. However, despite the growing research on this topic, the problems of lack of detailed information and standardization of methods remain unresolved. This review emphasizes the importance of applying unified methods and conducting long-term monitoring experiments in future research.

Abstract Land subsidence induced by underground coal mining consistently leads to persistent ponding in coal-grain overlapping areas (COAs), substantially impairing agricultural productivity. However, amid stringent farmland protection policies, mining operations face significant sustainability challenges. In this study, Guqiao Coal Mine in Anhui of China, is taken as a case, and four mining-reclamation schemes were conducted to compare patterns, and applicable conditions for each scheme are proposed based on concurrent mining and reclamation (CMR). Results show that: (1) Historically, traditional mining-reclamation (TMR) dominated due to low immediate reclamation costs despite extensive farmland loss; (2) Currently, earthwork-conserving CMR (ECMR) offers practical advantages by balancing economic investment and farmland reclamation. ECMR enhances land reclamation and reduces indirect costs, but leads to premature farmland degradation and prolonged compensation burdens; (3) Henceforth, reducing-degradation CMR (RCMR) can eliminate farmland degradation but is constrained by low coal-extraction rates, making it less feasible under current coal economic constraints; (4) In the prospective future, coupling CMR (CCMR) delays land degradation while improving reclamation efficiency, shortening the restoration cycle by 42% for ECMR, and raising coal-extraction rate to over 92% for RCMR. It restores 70% of degraded farmland and reduces seedling compensation costs by over 63 million yuan for ECMR in 30 years. CCMR also has strong performance in reducing surface ponding, maintaining grain security, and minimizing social displacement. Our findings underscore CCMR's superiority in aligning economic, ecological, and social objectives. It offers a replicable model for sustainable resource management in C1OAs globally, particularly under tightening environmental and agricultural policies.