Environmental Earth Sciences最新文献

Northwest Saudi Arabia's Harrat Lunayyir is a continental volcanic field with unparalleled seismic activity records. In 2009, this specific area experienced a huge surface rupture of 3 km due to seismic swarm include more over 30,000 earthquakes. To enhance the comprehension of relationship between seismic activities and post-seismic deformation, we combined various datasets, including Gravity Recovery and Climate Experiment (GRACE) data, Interferometric Synthetic Aperture Radar (InSAR) imagery, aeromagnetic surveys, and local seismic records. Our analysis shows that, (1) a rapid change in GRACE gravity anomalies about 2 ± 2 × 10⁻² µGal, (2) a significant increase in seismic activity, with some events ranging in magnitude from 4 to 6 ML within a single day, and (3) a clustering of shallow earthquake sources < 10 km. The research study provides new insights in geodynamic behavior and region’s response to tectonic stress and magmatic interactions, particularly in areas with similar tectonic setting. This integrated approach can also point out areas that might be at risk because of ongoing stress accumulation, helping to protect people and property in places facing similar threats around the world.

Groundwater quality in hard rock regions is increasingly threatened by intensive agricultural activities and geological factors, posing challenges for safe drinking and irrigation use. This study evaluates the spatial and seasonal variability of groundwater quality in this hard rock basin using integrated quality indices, irrigation suitability plots, and statistical analyses for the betterment of drinking and agricultural purposes. A total of 48 groundwater samples were analyzed before (PRM) and after the monsoon (POM) to assess major physicochemical parameters and their compliance with WHO drinking water standards. The results revealed that 22% of pre-monsoon and 10.4% of the post-monsoon samples were unsuitable for drinking based on the water quality index (WQI). Key contaminants such as potassium (K⁺), nitrate (NO₃⁻), and fluoride (F⁻) exceeded safe limits in several locations. Hydrogeochemical facies, including mixed CaMgCl, CaHCO_3, and NaCl, were identified using piper diagrams, indicating a longer residence. Groundwater quality deterioration was confirmed by the 85% shift of doubtful representations in post monsoon Wilcox’s results. The quality is in a medium level was observed from 10% to 15% class II indication during pre and post monsoon in Doneen’s plot. The groundwater saltiness is observed from the predominance C₃S₁ category in the USSL diagram. There was a strong correlation between Na with Cl, NO₃, and K. All these results indicated the improper agricultural practices in this region, which highly affected the groundwater chemistry. The findings underscore the need for seasonal monitoring and integrated management strategies to ensure sustainable groundwater use in hard rock terrains.

High prevalence of uranium in groundwater and associated potential health hazards to human population of Bathinda and Moga districts of south-west Punjab, India is presently a matter of great concern, as the groundwater is a major source of drinking water for human consumption as well as irrigation. So, the current integrated study was carried out to understand the spatial and vertical distribution of uranium, associated physico-geochemical parameters and allied path finder elements using hydro-geochemical tools of chemometric statistics. In this study, in comparison to the samples from deeper aquifers, high prevalence (surpassing WHO limit 30 µg/L in drinking water) of uranium was observed in 63% and 43% of groundwater samples from shallow depth (< 200 ft) in Bathinda and Moga districts, respectively. Substantial nitrates (mg/L) contamination (Bathinda: 0.16–525.20; Moga: 0.17–71.28) followed by fluoride (mg/L) (Bathinda: 0.56–2.67; Moga: 0.11–2.15) was found in groundwater of both districts. The health risk assessment revealed that cancer risk (CR) and hazard quotient (HQ) values decrease with groundwater depth, indicating higher uranium-related health risks in shallow aquifers, particularly in Bathinda district. The groundwater from deeper aquifers of the study area has been determined to be appropriate for irrigation purpose. From the hydro-geochemistry study in Bathinda district, it was observed that both water–rock interactions and high saline water intrusions were responsible for ionic solubility whereas in Moga district, the primary source of dissolved ions is water–rock interactions. Further, U mobilisation was found to be facilitated by the association of Ca-Mg-SO₄ in the saline groundwater. A strong positive correlation of uranium was observed with its path finder elements (Cr, Mo, Se) in both districts indicated that the geogenic sources are predominantly responsible for the origin of U in groundwater of two districts. So, this study may serve as a baseline dataset for uranium distribution in groundwater of both districts to local communities, state and central government and other associated organizations for designing the policies and remediation strategies to tackle water pollution.

The usability of rocks as dimension stones is influenced by several geological parameters, including the reserve, material properties, block size, quarry production efficiency, factory production efficiency, and the color-pattern characteristics of the rock mass. The initial preparation costs are particularly high in dimension stone quarries. Numerous dimension stone quarries are prematurely abandoned as a result of inadequate geological investigations conducted before production. This not only results in economic loss but also unnecessary destruction of nature. Consequently, an assessment of the rock mass characteristics and material properties is a critical factor to consider prior to initiating quarry operations. This study aims to identify the geological parameters influencing the production of dimension stone in Manisa limestone. In this context, detailed field observations were conducted on the bench faces and on the abandoned stone blocks in the waste disposal areas of 15 quarries (7 active and 8 abandoned) located in Manisa region. According to the findings of the geological studies conducted at the quarries, it was determined that the most important primary geological parameters affecting the dimension stone production are discontinuities; secondary geological parameters were determined as brecciation, cherts, autobrecciation, fossil presence, Neptunian dyke infillings, onyx zones, color changes, stylolites, weathering along discontinuity, and black dots. Results of the scan-line surveys shows that the mean discontinuity spacing of the discontinuity planes is wider than 1 m and the volumetric joint count (Jv) value is lower than 1.35 joint/m³ of the working quarries.

Research on cementation in natural moraine soils remains limited. To address this gap, a series of tests, including field surveys, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), grain sieve analysis, and a pretreatment using hydrochloric acid (HCl) and hydrogen peroxide (H₂O₂), were conducted. The results reveal that clay-carbonate cementation is widespread in moraine soils, which are primarily composed of clay minerals and calcite (CaCO₃). XRD analysis revealed a clay mineral content ranging from 6% to 27%, with illite as the dominant mineral. The calcite and dolomite content ranged from 0% to 9%. Scanning electron microscopy (SEM) and EDS mapping confirmed that the cementation enhances the connection and density of particles. Additionally, the pretreatment altered the cumulative grain size distribution (CGSD), reducing the gravel content and increasing the proportion of smaller particles, particularly those smaller than 0.25 mm. This shift resulted in changes in soil texture classification, from poorly graded gravel (GP) to fine and clayey gravel (GF and GC). A new Sigmoid-TL model was proposed to quantify cementation, using the absolute integral area between the fitted CGSD curves before and after pretreatment on a logarithmic particle size scale, thereby providing a reliable measure of its effect on soil cementation. The study highlights the significant role of cementation in enhancing slope stability, though external factors, such as acidic and alkaline rain, can weaken it, leading to increased instability.

As one of the most abundant and widely distributed aerosols in the troposphere, dust aerosols act as condensation nucleus to alter the life cycle of clouds and precipitation, thus affecting weather and climate. However, the exact effect of dust aerosols on precipitation, specifically polluted dust, remains to be fully understood and warrants further exploration. Based on raindrop size distribution data in Pudong, Shanghai, China, from 2021 to 2022, two precipitation episodes with polluted dust are taken as examples to clarify the mechanism of the inhibition of polluted dust on weak precipitation. Compared to the dust-free precipitation event, the average concentration of small raindrops increased by 13.8%, while that of large raindrops decreased by 19.2% in polluted dust precipitation event. This may be attributed to the participation of polluted dust aerosols in cloud microphysical processes, which led to the suppression of precipitation efficiency and the significant reduction of large raindrop concentration. However, anthropogenic aerosols have the opposite effect in convective precipitation. It is found that, compared with clean conditions, the average concentration of small raindrops in stratiform precipitation decreases by 63.5%, whereas that of large raindrops in convective precipitation increases by 8.04 times under high pollution conditions. These findings highlight the inhibition effect of polluted dust aerosols on weak precipitation and the promotion effect of anthropogenic aerosols on convective precipitation, which can provide scientific insights for weather and climate prediction.

Effective water resources planning and management require a robust understanding of groundwater level (GWL) dynamics, which in turn depends on the reliability of simulation models. Modeling GWL in anisotropic settings remains a significant challenge, particularly in poorly monitored basins. This study investigates a hybrid modeling framework that integrates state variables from the Water Partition and Balance (WAPABA) model into Extreme Gradient Boosting (XGBoost), Support Vector Regression (SVR), and Shapley Additive Explanations (SHAP) algorithms to improve GWL prediction in the Bouregerg Catchment in Morocco. The WAPABA model demonstrated strong performance in simulating runoff, achieving Nash–Sutcliffe Efficiency (NSE) values of 0.88 and 0.77 during calibration and validation, respectively. Sobol sensitivity analysis identified key parameters, including the catchment consumption curve and groundwater yield proportion. Incorporating WAPABA-derived state variables into SVR and XGBoost models substantially enhanced GWL prediction, yielding NSE values between 0.53 and 0.96 and Kling–Gupta Efficiency (KGE) values between 0.779 and 0.962. SVR exhibited a slight performance advantage over XGBoost, and the hybrid models consistently outperformed standalone machine learning approaches. SHAP-based interpretability analysis highlighted the dominant influence of hydrological state variables such as potential evapotranspiration, soil water storage, and groundwater fraction on GWL dynamics, with their relative importance varying according to geological conditions. Overall, the proposed hybrid framework offers a powerful and process-consistent approach for modeling GWL in anisotropic environments, supporting improved decision-making in water resources management.

Over the past three decades, China’s coal production has undergone a strategic westward shift. Several important coal production bases are now located in ecologically fragile, arid regions. The surface subsidence caused by large-scale coal mining could adversely affect these vulnerable ecosystems. To understand this impact, this study investigates the moisture migration process and evaporation losses of fissure-filled soil moisture in semi-arid mining areas. We collected fissure-filled and undisturbed soil samples from depths of 0-300cm, analyzed their structure and soil moisture content (SMC), and used hydrogen and oxygen stable isotopes ((delta ^2 H) and (delta ^{18} O)) to trace soil moisture infiltration and evaporation processes. This study revealed distinct structural differences between fissure-filled soil and undisturbed soil layers. Fissure-filled soil received more precipitation recharge, resulting in higher moisture content in deeper layers. Conversely, the shallow layer of fissure-filled soil experienced stronger evaporation. Consequently, the evaporation loss rate within the fissure-filled soil in the 0-180cm depth range was 10-20% higher than that of the undisturbed soil. The results show that after the tension fissures in the coal mining subsidence area are filled, fissure-filled soil texture changes, the deep soil moisture content increases, and the evaporation in the shallow layers are intensified. This leads to more frequent and severe soil dry-wet cycles within fissure-filled soil. Furthermore, the fissure-filled soil exhibits enhanced water recharge capacity, suggesting its potential as a hotspot for ecological reclamation in arid mining regions.

Acid rain can dissolve carbonate rocks and affect karst carbon sinks. This study investigated the effect of acid rain on the dissolution of carbonate rocks within a karstic soil–carbonate rock system and quantified the relationship between the carbon sink and karst carbon sink flux. A subtropical karst spring catchment in southwestern China was chosen as the study area. The hydrochemistry of acid rain and spring water, along with the δ¹³C of dissolved inorganic carbon (DIC), was systematically monitored. NH₄⁺, H₂SO₄, and HNO₃ from precipitation contributed 3.57%, 3.49%, and 1.57% to carbonate rock dissolution, and 1.74%, 1.70%, and 0.77% to groundwater DIC, respectively. These acidic ions reduced the karst carbon sink flux by approximately 17.37%. The carbon sink flux reached 43.93 mg C/L during the wet season, whereas the karst carbon sink flux was 11.61 mg C/L. Overall, the total carbon sink flux in the spring catchment was about 3.8 times higher than the karst carbon sink flux. The dissociation of carbonic acid produces H⁺, which can be exchanged with soil base ions. This process contributed more DIC to groundwater in the Yaji karstic soil–carbonate rock system than direct carbonate rock erosion by H⁺ from carbonic acid dissociation. While this study demonstrates that karstic soil processes significantly buffer acid rain and strengthen the carbon sink effect, their wider applicability may be limited by site-specific factors such as soil composition, hydrological conditions, and land use.

The long-term environmental legacy of mining in sulfide-rich regions remains a critical concern due to the persistent generation of acid mine drainage (AMD) and the mobilization of potentially toxic elements (PTEs). This study presents a comprehensive, site-specific assessment of mine waste from two contrasting geochemical zones, Nuestra Señora del Carmen (NSC) and Volta Falsa (VF), within the historically under-characterized Trimpancho Mining Complex, located in the Iberian Pyrite Belt (IPB). A multidisciplinary approach combining mineralogical characterization, physicochemical and geochemical analyses, multivariate statistics, and contamination indices, provided insights into the behavior, mobility, and ecological risk of key PTEs such as Cu, As, and Zn. The NSC zone is dominated by pyrite and secondary sulfates, promoting acidic conditions (pH values ranging from 2.42 to 3.60) and high Cu mobility, whereas VF waste materials show a more heterogeneous mineralogy, higher pH (ranging from 2.77 to 5.05), and broader PTE enrichment. Principal Component Analysis revealed distinct geochemical regimes shaped by the presence of sulfides or silicates. Contamination indices underscored significant ecological risk in both zones, but with distinct pollution signatures. This integrated framework supports site-specific environmental risk management and remediation strategies and applies to other AMD-impacted volcanogenic massive sulfide (VMS) mining environments facing renewed exploration pressures.