Environmental Earth Sciences最新文献

Cutting operations are one of the main anthropogenic factors altering forest ecosystems. The article presents the results of a model experiment on soil and soil organic matter (SOM) changes after cutting using a harvester and forwarder. In the territory of the middle taiga of the European northeast of Russia (Komi Republic), soils (Albic Retisol (Siltic, Cutanic)) of the original forest (OF) before cutting and the site after cutting (UDFA) were studied. A number of plots with different degrees of mechanical disturbance were laid: plots with three forwarder passes (3P), plots with ten passes (10P) and plots with ten passes and leveling (10R). A comprehensive study of SOM was performed using modern methods: determination of the content of total organic carbon (C_tot) and nitrogen (N_tot), assessment of the content of water-soluble forms of carbon (C_ws) and nitrogen (N_ws), calculation of their stocks, isolation of physical fractions of SOM by densimetric fractionation – free particulate organic matter (fPOM_< 1.6), occluded particulate organic matter (oPOM_< 1.6), heavy fraction (MaOM_> 1.6), assessment of molecular fragments in the composition of SOM by ¹³С-Nuclear magnetic resonance spectroscopy (CP-MAS ¹³C-NMR). The conducted studies show a significant impact of cutting on SOM. An increase in the C_tot in the upper mineral horizons (E) of soils after cutting (up to 9.3 ± 2.1 ^{g kg–1}) compared with the initial values (4.5 ± 1.0 ^{g kg–1}) was revealed. In the upper horizons of soils subjected to mechanical stress (TUR), a significant increase in C_tot by 3–6 times and N_tot by 2–4 times was revealed. An increase in the C_ws content was found in both organic (up to 33.4 ^{g kg–1}) and mineral horizons (up to 1.15 ^{g kg–1}) of the studied soils. The calculation of carbon stocks showed that after cutting, there was an increase in its stocks from 4.5 to 13.5 ^{kg m–2} due to mixing of the mineral part of the profile with the organic horizon and coarse wood residues. An increase in the content of fPOM_< 1.6 and oPOM_< 1.6 fractions in the upper mineral horizons of the soils of the disturbed areas was found by 2–12 times compared with the soil of the original forest, which led to an increase in the carbon contribution of these fractions to the total soil carbon (up to 66%). Assessment of the content of molecular fragments of the upper organic horizons and mineral horizons by 13 C-NMR spectroscopy showed an increase in the content of aromatic fragments in the SOM composition from 17.1% to 43.3% in the third year after cutting. Thus, diagnostic compounds and fractions of organic matter that can be used for predictive purposes and in assessing the state of natural ecosystems have been identified.

Residential radon remains a research gap in Argentina, as in most South American countries. In this context, the present study reports the first 281 indoor radon measurements in dwellings and institutional buildings from the Punilla region (Córdoba, Argentina) to discuss the influence of geologic and architectural factors. Radon levels ranged from 6 to 307 Bq/m³ (mean = 46 Bq/m³), with 6% exceeding the WHO guideline of 100 Bq/m³. Radon concentrations decreased by 41–87% from winter–fall to summer–spring, underscoring the need for a seasonal correction factor even in comparable temperate regions. Moderate to weak statistically significant correlations are detected between radon concentration and number of floors of the building (inverse), openings of the sampled room (inverse), and building age (direct). Sampled room size may account for higher radon concentrations (inverse). No patterns were identified between radon and building materials used in floors and walls of sampled rooms. Besides architectural features, geology remains the primary control in ˃100 Bq/m³ cases. Elevated concentrations are associated with the Achala Batholith and the Capilla del Monte granitoid, both characterized by relatively high uranium contents, whereas lower radon values are generally found in Paleozoic metamorphic and Quaternary unconsolidated units. Additionally, scattered high-radon cases along the western flank of the Sierra Chica indicate a contribution from the Sierra Chica Fault System. These results emphasize the importance of incorporating natural radioactivity into land-use planning and public health, particularly in Punilla, which is undergoing a rapid urban expansion.

The loess-paleosol sequence of the Loess Plateau, with its distinct microstructural characteristics, provides critical insights into paleoclimate and soil formation. This study investigates a 52.7-meter-thick loess-paleosol profile (L₀-S₉ layers) in the southern Loess Plateau of China using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The analyses focus on the microstructural characteristics and their depth-dependent variations. Marked differences were identified between loess and paleosols regarding particle morphology, contact relationships, pore structure, and cementation, as analyzed through particle size distribution, quantitative pore characteristics, and mineral composition. The results show that loess predominantly comprises clay particles and clay-silt aggregates, featuring scaffolding pores and weak cementation. In contrast, paleosols consist primarily of clay-silt aggregates characterized by mosaic and cemented pores with notable cementation. As burial depth increases, structural differences between loess and paleosol progressively diminish, particularly in the middle and lower layers, where increased viscosity and cementation strength lead to a denser microstructure. Moreover, these microstructural changes are intricately linked to climatic fluctuations. A comparative reference to the Duanjiapo (DJP) profile, based on published datasets of silt content, magnetic susceptibility, and δ¹³C, highlights that the microstructural evolution in the Liujiapo (LJP) section corresponds to wet-cold and dry-cold climatic cycles in the southern Loess Plateau. During glacial periods, the intense winter monsoon promoted the accumulation of silt particles and loess deposition, while the warm, humid interglacial phases facilitated weathering and leaching, forming paleosols. This study deepens understanding of loess-paleosol microstructural dynamics and their ties to paleoclimate, offering a foundation for future research on loess formation and its role in climate studies.

Groundwater plays a vital role in drinking and daily supply in the Islamabad-Rawalpindi metropolitan areas. The current study is designed to comprehensively address the problem of groundwater quality using a multi-methodological approach with water quality indices (WQI). For this purpose, 122 observations were recorded and analyzed following standard procedures. Piper and Gibbs diagrams demonstrated groundwater characterization. The GIS and multivariate statistical analyses were employed for vulnerability assessment and source apportionment. The findings of the present study revealed that certain parameters (pH, alkalinity, bicarbonates, and potassium) were within the desirable range stipulated by the WHO and PSQCA. However, groundwater quality impairment is related to toxicities of EC, TDS, turbidity, TH, calcium, magnesium, sodium, chlorides, sulfates, nitrates, fecal, and total coliform. The WQI indicated that the study area exhibited poor to very poor groundwater quality. Irrigation indices explained that it is suitable or marginal at most studied sites, and only a few sites displayed unsuitable quality. Piper and Gibbs diagrams suggested that groundwater belongs to Ca-HCO₃ and Ca-Mg-HCO₃ or mixed types influenced by rock-water interactions and evaporation. Statistical analysis deciphered that anthropogenic and geogenic factors are the key determinants of water quality in the study area, including Lei recharge, domestic, agricultural, and industrial effluents, improper waste disposal, poor maintenance, and weathering processes. The study provides benchmark groundwater quality data that decision-makers can utilize to take appropriate measures for groundwater monitoring and pollution risk management in the twin cities.

CO₂ sequestration into coal seams, coupled with enhanced coalbed methane recovery (CO₂-ECBM/sequestration), is increasingly recognized as a viable strategy for achieving global carbon neutrality objectives. This approach is particularly relevant in regions characterized by deep, unmineable coal seams or abandoned goafs resulting from the complete extraction of coal from mining fields. The adsorption of CO₂ on coal provides critical data necessary for CO2-ECBM/sequestration. This study systematically investigates the scientific challenges associated with quantifying CO₂ adsorption on coal using the manometric method under high-pressure conditions. It primarily addresses several key factors: the calculation of CO₂ density using the equation of state, the accuracy of temperature and pressure sensors, the implications of the CO₂ Joule-Thomson effect, phenomena related to coal adsorption swelling, and inconsistencies in temperature distribution within sample and reference cells. These issues can distort CO₂ adsorption measurements, rendering coal isotherms unreliable. Consequently, such factors may compromise both reproducibility and repeatability in supercritical CO₂ adsorption experiments conducted under high pressure, ultimately leading to distortions in the isotherms and negative adsorption profiles.

Extreme temperature fluctuations in cold regions significantly influence freeze-thaw damage to rock formations, with important implications for groundwater systems and slope stability in alpine environments. This study employs laboratory freeze-thaw experiments coupled with a mesoscopic numerical model based on the discrete element method to investigate the deterioration mechanisms of rocks under freeze-thaw cycles (FTCs) at varying cooling rates. The findings reveal that cracks primarily form on the rock sample perimeter rather than the interior during freeze-thaw processes, propagating inward from the outer surface, with propagation rates positively correlated with cooling rates.The damage coefficient increases with higher cooling rates, leading to a 45.51% and 51.21% reduction in peak stresses for rock species, while strain at failure under uniaxial compression increase by 48.23% and 67.73% at cooling rates of 0.8 °C/min and 2 °C/min, respectively. As the cooling rate escalates, rock specimens exhibit more complex damage characteristics, displaying Y-shaped composite damage patterns, with rupture zones coinciding with crack locations. Increased porosity in sandstone, resulting from higher cooling rates, leads to a greater content of unfrozen water within pores, amplifying the freezing force exerted on the rock. Porosity evolution dynamically governs hydrological properties and reduces rock strength in fractured systems, thereby dictating macroscopic damage patterns. This integrated experimental-numerical study elucidates rock deformation and degradation under extreme thermal fluctuations and freeze-thaw cycles, highlighting cooling rate as a master variable governing mechanical property evolution and cold-region environmental impacts.

This study examines the topographic and erosional asymmetry of the Otoishi River watershed (ORW) in Kyushu, Japan, by integrating high-resolution LiDAR-based terrain analysis with long-term landscape evolution modeling. Hilltop curvature and hillslope length were calculated across eastern and western sub-watersheds. Systematic differences in morphology were identified, reflecting spatial variability in erosion processes and subsurface hydrology. These patterns correspond to variations in silica flux and sediment dynamics. Numerical simulations were performed using the Landlab framework with both real and synthetic DEMs. Uplift rates and erodibility parameters were varied to assess their impact on landscape development. Results show that low (varvec{D}/varvec{K}) ratios—where (varvec{D}) is hillslope diffusivity and (varvec{K}) is fluvial erodibility—preserve ridge variability, while high (varvec{D}/varvec{K}) ratios promote convergence in hillslope form. These outcomes support a conceptual link between geomorphic uniformity and erosional regime. The results are consistent with chemostatic behavior in the stable western region and with prior observations from sediment disasters and climatic trends. This integrated approach offers insights into the interactions among climate, tectonics, and surface processes, contributing to the understanding of landscape evolution and geomorphic stability in humid mountainous regions.

For the first time, a coastal vulnerability index is calculated at a regional level for the Greek coasts with a focus on the coastal protection ecosystem service provided by natural habitats, through the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) coastal vulnerability model. The examined species is the Posidonia oceanica seagrass. Posidonia meadows are broadly acknowledged to act as a Nature-Based Solution (NBS) for coastal protection, especially when conserved or restored, since they may reduce the wave action and sediment transport in coastal areas and, thus, contribute to coastal erosion risk mitigation. This is particularly important for the study area, as a large portion of the Greek coastline is considered vulnerable and also favorable for the growth of seagrasses, suggesting the potential adoption of sustainable measures for coastal protection. The results indicate that the majority of Greek coasts can possibly benefit from the improved coastal protection afforded by Posidonia oceanica meadows. Emphasis is given to the coastal sites where the provided service is more likely to be efficient, due to favorable local conditions and seagrass meadows spatial extent. These sites include locations in the Zakynthos, Limnos, Milos and Kos islands, and Kassandra Peninsula. The present work meets the global initiative for seagrass protection and restoration, while its provided evidence can be used for prioritizing actions in relative scientific programs as well as for future research in coastal zones, which are highly recommended in order to implement NBSs in realistic terms and support ecological engineering in Greece.

Most of Brazil’s natural waters are stored in aquifers, with great potential for meeting supply demands. A comprehensive environmental management is, thus, fundamental for preserving this resource and preventing threats to human health and to the environment. Nonetheless, practices are heterogenous throughout the country; the legislation in the wealthiest state, Sao Paulo, has been historically a reference at a federal level. The database from the environmental agency of the state of Sao Paulo was analysed, particularly the cases of contaminated sites by chlorinated solvents. Not only these are a major industrial contaminant, but contaminated industrial sites are notably underestimated in the state registry. An in-depth analysis revealed a challenging scenario in which many private supply wells are within or neighbouring potentially or known contaminated areas. Additionally, despite the common environmental and contamination complexities, the pace of rehabilitation in industrial sites surpasses the average discovery of new contaminated sites, bringing attention to efficiency and the accuracy of the remediation methods applied. Finally, the need to advance the approach when dealing with complex industrial contaminated sites in Brazil is discussed. The key challenges highlighted in this work include complex and heterogeneous nature of subsurface environments, gaps in existing legislation to present a framework for groundwater monitoring and management, and limitations of government structure.