Environmental Earth Sciences最新文献

Groundwater is an important resource, but contamination-related safety threats and the need for accurate and consistent evaluation are substantial. Therefore, in the current research, groundwater samples (n = 237) were collected during the pre-monsoon season (May–June 2024) from Raipur District, Chhattisgarh, Central India, and evaluated drinking water quality using eleven physico-chemical parameters through a Water Quality Index (WQI), the Entropy Water Quality Index (EWQI), and a newly developed Self-Organizing Map-based Water Quality Index (SWQI). The adopted quality indexing methods were also validated and compared by replicating the computations using a different dataset sourced from the study area. Analysis demonstrated high reliability of SWQI with precision (0.952), rationality (0.985), robustness (0.977), and versatility (0.918); uncertainty of only 03% from error using Monte Carlo simulations, which is high fidelity and supports the trustworthiness of proposed SWQI method for the assessment of groundwater quality. The present study also used four Machine learning (ML) algorithms including Random Forest (RF), Gaussian Process Regression (GPR), Support Vector Machine (SVM), and Deep Learning (DL) Machine learning (ML) algorithms to predict the groundwater quality indices. Results showed that DL had the best accuracies, in terms of coefficient of determinations (R² = 0.909, 0.960, and 0.985) while predicting WQI, EWQI, and SWQI. The research illustrates that SOM-based indices are valuable for groundwater quality assessment that can be integrated within ML to provide accurate groundwater quality prediction, which can then inform sound water resource management strategies to offer resource sustainability and water safety.

Layered rock bodies are widely distributed in the Earth’s crust and exhibit significant discontinuities and anisotropy, resulting in complex mechanical properties. To investigate the spatiotemporal evolution and deformation characteristics of layered composite rock failure, this study prepared soft–hard composite rock specimens with varying soft rock thickness proportions based on similarity theory. Uniaxial compression tests were conducted in conjunction with three-dimensional digital image correlation (3D-DIC) technology. The results indicate the following: A significant negative correlation exists between the soft rock thickness proportion and the mechanical properties of the composite rock. When the soft rock proportion increased from 10% to 90%, the peak strength and elastic modulus decreased by 63.4% and 36.8%, respectively. Axial strain of soft and hard rock decreased gradually with increasing soft rock proportion. Radial strains show significant differences: the hard rock radial strain initially increased and then decreased, whereas the soft rock radial strain consistently diminished, indicating that a higher proportion of soft rock had a more pronounced effect on its radial strain. Strain concentration zones first emerged in the soft rock, whereas deformation in the hard rock zones lagged. As the proportion of soft rock increased, the failure mode of the composite rock transitioned from being hard rock-dominated to soft rock-dominated mechanisms and displacement gradually decreasing from high to low across different locations. The quantitative relationship between surface strain recorded by DIC tests and the damage factor can effectively reflect the entire process of rock failure. The damage evolution equation established on this basis exhibits good agreement with experimental data, demonstrating its rationality.

Biochar, as a carbon-enriched porous material obtained via pyrolysis of biomass in anoxic environments, exhibits significant potential for application in soil remediation and carbon cycle management due to its unique physicochemical properties. This article reviews the application and action mechanism of biochar in the remediation of heavy metals and organic pollutants contaminated soils, and the effects of carbon sequestration. The remediation of heavy metals involves a complex interplay of physical adsorption, ion exchange, surface complexation, co-precipitation, and redox reactions. For organic pollutants, adsorption mechanisms such as pore filling, hydrophobic partitioning, and π-π interactions are paramount, alongside biochar-facilitated microbial degradation. Furthermore, the review details how biochar application promotes soil carbon sequestration by directly introducing stable carbon, influencing soil organic matter dynamics, fostering aggregate formation, and modulating microbial communities to reduce greenhouse gas emissions. Despite its potential, significant challenges persist, including the long-term stability of biochar, the risk of pollutant remobilization upon aging, and context-dependent performance influenced by soil properties. This review not only systematically explores its mechanism of action, but also aims to provide crucial theoretical support and forward-looking research directions for the design of multifunctional biochar materials and the realization of the synergistic effect of pollution control and carbon neutrality.

This study examines the hydrogeochemical processes that regulate groundwater and surface water quality in the El Salado Basin, a volcanic-geothermal region in western Mexico. Seasonal sampling during spring and summer included thermal springs, wells, and surface waters to evaluate major ions, physicochemical parameters, arsenic, and boron. Piper diagrams, principal component analysis, clustering, and spatial interpolation were applied to identify dominant processes and seasonal patterns. Results show that sodium-bicarbonate facies and elevated As-B concentrations are controlled by geothermal water-rock interaction in zones influenced by the La Primavera Volcanic Field. Seasonal dilution during summer reduces solute concentrations, while redox and evapoconcentration effects modulate trace-element mobility. Interpolation maps demonstrate that arsenic hotspots coincide with geothermal discharge areas. The findings clarify the geogenic origin of arsenic in the basin, reveal how seasonal hydrology reorganizes hydrogeochemical signatures, and provide a methodological framework for interpreting trace-element mobilization in volcanic aquifers.

Groundwater serves as a crucial source of drinking and irrigation water in the Cixian area of the Fuyang River Basin (FRB) in northern China. Assessing its quality is essential for sustainable resource management. In the present study, hydrochemical diagrams, multivariate statistical methods, and human health risk models were used to reveal the processes controlling groundwater quality and associated health risks. The results showed that the quality of pore groundwater (PGW) was poor, and dominated by HCO₃·SO₄-Ca and HCO₃·SO₄-Ca·Mg hydrochemical facies with high total dissolved solids (TDS) value. The main indicators influencing groundwater quality included SO₄^2–, NO₃^–, Cl^–, Na⁺, TDS, and total hardness (TH). The quality of fissure groundwater (FGW) was relatively good, mainly composed of HCO₃-Ca and HCO₃-Ca·Mg facies, with only a few samples exceeding the permissible limits. The quality of PGW was influenced by both water–rock interactions and anthropogenic activities, whereas that of FGW was predominantly controlled by natural conditions. The human activities mainly included agricultural activities, industrial production, and domestic sewage discharge. The health risk assessment (HRA) model showed that half of PGWs posed a potential health risk to children and infants, whereas over two-thirds of FGWs were safe for all age groups. The results will provide a scientific basis for the development and utilization of groundwater in arid and semi-arid regions in northern China.

The Sikkim Himalaya, situated in the North-East Himalaya, is susceptible to landslides induced by precipitation, anthropogenic activities, and various natural calamities. This study aims to evaluate landslide potential in East Sikkim by developing a precise Landslide Susceptibility Map (LSM) with high conservativeness and examining the individual and combined effects of two statistical methods, such as, Evidence Belief Function (EBF) Method and the Frequency Ratio (FR) method, on landslide susceptibility. A further objective was to evaluate whether high model accuracy necessarily corresponds with a conservative prediction. Here, conservativeness is defined as a model’s inclination to err on the safer side by prioritizing the avoidance of failing to detect landslide-prone zones. This study considers twenty causative factors for landslides, including: Elevation, Slope, Aspect, Profile Curvature, Relief Amplitude, Topographic Wetness Index (TWI), Topographic Roughness Index (TRI), Roughness, Sediment Transport Index (STI), Stream Power Index (SPI), Topographic Position Index (TPI), Distance to Drainage (DTD), Distance to Lineament (DTL), Rainfall, Lithology, soil Geomorphology, Land Use Land Cover (LULC), Normalized Difference Vegetation Index (NDVI), Distance to Road (DTR) have been created utilizing diverse data from multiple sources in ArcGIS environment. Eight scenarios corresponding to individual EBF, FR, and the ensemble of these methods have been developed. After developing these scenarios, LSMs have been developed for each scenario. The accuracy of each LSM has been examined by the Receiver Operating Characteristic (ROC) curve. It has been demonstrated that an ensemble of different methods may sometimes help in increasing LSM accuracy. This study indicated that high accuracy does not necessarily equate to a conservative LSM; hence, LSM conservativeness should be evaluated in conjunction with accuracy prior to making recommendations. High accuracy and conservative LSM for East Sikkim has been attained in this study.

The article is devoted to the study of the activity of radionuclides of natural and anthropogenic origin in the bottom sediments of the Pechora River delta lakes, which represent the largest river in the European sector of the Arctic Ocean Basin. The study revealed that the average activities of the radionuclides ¹³⁷Cs, ²¹⁰Pb, ²²⁶Ra, ²³²Th and ⁴⁰K in the lake bottom sediments are 2.7, 22.6, 18.3, 25.4 and 535.9 Bq/kg, respectively. The mean values of total alpha and beta activities of the bottom sediments are 334.8 and 720.7 Bq/kg, respectively. These values are commensurate with the global average, thereby signifying a minimal level of natural and anthropogenic radioactivity in the Pechora delta lakes’ sediments. The data on physical and chemical parameters demonstrated that the flooded lakes of the Pechora delta are characterized by a relatively weak manifestation of sedimentation and biological processes. This is due to the hydrological regime of the delta (flooding of lakes during flood periods, daily tides) which prevents active accumulation of fine mineral and organic material in the lakes. The profound impact of hydrological conditions within the Pechora delta is evident in the disorderly vertical distribution of physico-chemical parameters and radionuclide activities across the depth of bottom sediment columns. The data obtained on radionuclide activities and physico-chemical parameters has enabled the estimation of the role played by flooded delta lakes as a component of the Pechora estuary system in the accumulation of pollutants. However, the vertical distribution of radionuclides in bottom sediments of these lakes has been found to be an unreliable indicator of the chronology of pollutant loads in the Pechora basin. This is due to the Pechora delta’s complex hydrological regime, which ensures the uneven flow of mineral and organic material into the lakes over time. The study of lake chronology is complicated by the manifestation of thermoabrasion (destruction) of lake shores, which is characteristic of permafrost development areas and which ensures the inflow of additional volumes of terrigenous material into lake basins.

This research examines the spatiotemporal scrutiny of droughts and heatwaves in the high Barind Tract of Northwestern Bangladesh and how they relate to vegetation, soil moisture, and groundwater levels. The research employs a novel methodology, combining the meteorological-based Standardized Precipitation Index (SPI) and remotely sensed land surface temperature (LST) to compute heatwave metrics and droughts. The connection between extreme occurrences with vegetation and soil moisture is examined using the normalized difference vegetation index (NDVI) and the normalized difference moisture index (NDMI). The findings show that the frequency, period, and severity of heatwaves in the area have significantly increased. The SPI values and Groundwater table (GWT) depth have a robust association, with increasing SPI values corresponding to GWT regaining and vice versa. Sometimes, even with positive SPI values, the GWT depth constantly rises. Changes in cropping patterns and overuse of groundwater are to blame for this. Drought threatens the groundwater-based agricultural practices used in the Barind area. The research confirms that arid or semi-arid regions are hydrologically vulnerable to extreme events and highlights the need for future mitigation and adaptation plans.

Currently, the deterioration of groundwater quality (GWQ) is a major global issue, largely due to a fast-growing population and increased agricultural and industrial activities. It is crucial to assess GWQ using effective methods to mitigate the risk of water contamination. In recent years, there has been a notable focus on using water quality index (WQI) values for measuring GWQ. A key step in creating WQI values is to assign weights to GWQ parameters. Even a slight change in these weights can significantly impact the overall GWQ assessment. Various weighting tools are employed in developing WQIs to reduce bias in weight assignment and improve the GWQ evaluation. A thorough review is essential to understand the characteristics of these indices in the context of GWQ assessment for drinking (GWQAD). The goal of this study is to review several weighted-WQI techniques for GWQAD, providing an evaluation of their attributes. A total of 1662 published documents were collected from the Scopus database covering the past two decades (2004–2024). A total of 344 published articles were filtered, which included seven weighted-WQI techniques. The framework, mathematical formulations, applications, advantages, and drawbacks of those WQIs have been discussed. Most models adhere to similar frameworks, although the specific details of the five critical phases vary considerably. Weighted-WQIs are widely used for GWQAD, but each model has distinct strengths and weaknesses, which create challenges for researchers. Therefore, we suggest that a comparative analysis of WQIs will assist in identifying the most suitable WQI method. This review could act as a reference, paving the way for future research endeavors.

Groundwater exploration plays a crucial role in securing sustainable water resources, a fact that is particularly evident in the context of aquifers and catchments. It is imperative to comprehend the subsurface hydrological situation in order to identify the geological structures that control the occurrence and flow of groundwater. Hydrogeophysics is a comprehensive field that utilises geophysical methods to enlighten groundwater-related geological structures. This study presents the findings of an integrated geophysical investigation conducted in a catchment located within Kırkağaç Graben, western Türkiye. To image spatial distributions of subsurface electrical and seismic properties in both two and three dimensions, four complementary geophysical methods were employed: electrical resistivity tomography (ERT), direct current induced polarization (DCIP), self-potential (SP) and seismic refraction tomography (SRT). The catchment was therefore determined, and the interaction between fault and water discharge points was revealed by joint interpretation of the geophysical results. The ERT method yielded information about lithology-derived resistivity variations, while the DCIP method gave a strong response to clay content of geological units. Groundwater flow was predicted based on SP anomalies. Finally, the SRT data demonstrated the P-wave velocities indicating variable water saturation conditions in shallow geological layers. Notably, groundwater rising along the fault zone, which acts as a barrier, was delineated. Furthermore, the buried fault identified beneath the recent sedimentary deposits was interpreted as the youngest structural element of the graben. The findings underscore that the near-surface catchment is vulnerable to anthropogenic influences such as urbanisation and should therefore be subject to protection and sustainable management.