Earth and Environmental Sciences

The evolution of groundwater in the Puhe River Basin is closely related to the ecological security of the Beijing–Tianjin–Hebei water source conservation zone. Based on 122 groundwater samples, this study systematically investigated the hydrochemical characteristics, evolution mechanisms, and water quality of shallow groundwater using mathematical statistics, Piper diagrams, ionic ratio analysis, and a variable fuzzy pattern recognition model. The results showed that shallow groundwater in the middle and upper reaches is generally weakly alkaline, fresh to hard water, with HCO3–Ca and HCO3·SO4–Ca as the dominant hydrochemical facies. Groundwater hydrochemistry is primarily controlled by rock weathering, and the dissolution of silicate and carbonate rocks is the main source of major ions. Calcite and dolomite are in dynamic equilibrium between dissolution and precipitation, whereas gypsum and halite remain undersaturated. Overall, groundwater quality is generally good; however, anthropogenic activities in cultivated and construction lands have altered local hydrochemical composition and caused water quality deterioration in some areas. These findings improved the understanding of groundwater hydrochemical evolution in typical small watersheds of the northern Hebei hilly region and provided a scientific basis for the sustainable management and protection of groundwater resources in the Beijing–Tianjin–Hebei water source conservation area.

of APPs. While rosin serves as a tracer for APP quantification, the environmental concern primarily relates to the overall paint particles, which contain biocides and other additives. This method provides a robust approach for the trace-level quantification of APPs in complex matrices.

Changes in past East Asian climate and monsoon intensity have been inferred from a wide variety of paleoclimate archives. However, quantitative reconstruction of land surface temperatures in East Asia remains sparse. Here we present a 75-kyr temperature record derived from the carbonate clumped isotope composition (Δ 47 ) of land snail shells from a loess-paleosol sequence at Yuanbao, on western edge of the Chinese Loess Plateau (CLP). Modern growing season (mid-April to September) temperature based on Δ 47 (T 47 ) is 21.2 ± 1.2 °C. The T 47 record reveals that there are certain periods where land surface temperatures were lower: the last glacial maximum (LGM) was ∼7 °C colder, Marine Isotope Stage 3 (MIS3) ∼5 °C and MIS4 ∼6 °C, but also the mid-Holocene was ∼9 ℃ colder than present day. Temperatures similar to present day occurred during Northern Hemisphere Summer Insolation (NHSI) minima within MIS3 and the Bølling-Allerød (BA). Monsoon precipitation reconstructions based on organic and inorganic geochemical proxies from the same loess-paleosol section indicate that these warm periods are characterized by relatively dry conditions. This is further supported by the relative enrichment in the temperature-independent oxygen isotope composition of snail body water (δ 18 O bw ) during these time intervals, reflecting a negative moisture balance. In contrast, the unexpected low T 47 for the mid-Holocene could be the result of wet conditions. Our record thus suggests that soil moisture availability exerts a strong influence on land surface temperatures recorded by snails stored in loess archives. • We present a 75-kyr clumped isotope temperature (T 47 ) record for the western CLP. • Modern snail T 47 reflects land surface growing season temperature. • Last glacial T 47 was ∼7 °C lower than present. • T 47 and snail body water-δ 18 O show a coupling between temperature and hydroclimate. • Hydroclimate strongly modulates land surface temperatures recorded by snails.

• Previous experiments used temperature to expedite soil phosphorus sorption reactions. • Soil phosphorus temperature studies often ignore biochemical and biological processes. • Users should be conscious of the potential information lost during extrapolation. By employing the Arrhenius equation to model the thermodynamic variations in soil solution phosphorus (P), researchers may hypothetically incubate soil at higher temperatures to shorten the time required to complete identical reactions at lower temperatures. However, there is no well-laid-out framework available, nor is there an adequate exploration in the literature of how temperature extrapolation impacts the soil P cycle. Consequently, this review examines how temperature affects soil solution P concentrations, previous breakthroughs, the complete methodology, and the key shortcomings identified by the authors. First, we explore how temperature affects soil P processes (i.e., sorption–desorption, precipitation-dissolution, and immobilization-mineralization) and whether the literature supports the use of the Arrhenius model. While most investigations examining temperature and the Arrhenius equation focused on sorption–desorption, omitting investigations of precipitation-dissolution may have overestimated the results. Furthermore, some P mineralization-immobilization reactions deviate from the Arrhenius equation and requires a separate model to describe reaction rates above optimal temperatures. The review clarifies and explores the methodology used to shorten the time needed to accelerate soil P reaction rates. Foremost, we argue for concurrent measurements of biochemical and biological processes to confirm the dominance of abiotic reactions. Finally, the review considers the limitations, and methodological best-practices (including the recommended soil test) before employing the technique. As soil researchers stress the requirement for novel methodologies to probe previously unexamined parts of the soil P cycle, an introduction to the concept provides an opportunity to harmonize temperature for time extrapolation practices while avoiding erroneous results.

The pollution of water, including salt and fresh water, has become an emergency problem. Pollutants come from different sources and have various characteristics, starting from industry and fertilizers used in agriculture, sewage related to human living, and other sources. Diverse sources of pollution require a comprehensive approach to water purification. One possible approach may be the use of appropriate sorbents. Currently, one of the most promising materials used is zeolites. This is because they can come from various sources, including waste raw materials such as fly ash, and, therefore, allow for the use of a circular economy approach. Moreover, these materials can be modified, which enables their selective use for selected types of pollutants. Eventually, these materials become economically viable options. The main aim of this article is to present and analyze possible solutions to water pollution based on zeolite materials. For this purpose, a critical literature review was prepared. The review reveals that zeolites perform particularly well in ion-exchange-driven removal of inorganic contaminants, while their effectiveness for organic micropollutants under realistic conditions is often limited. The identified trade-offs between removal efficiency, regeneration stability, and scalability indicate that zeolites are best applied as function-specific rather than universal sorbents. From a sustainability perspective, this targeted applicability is supported by advantages, such as low material cost, long service life, and the possibility of using naturally occurring or waste-derived precursors, which, together, enable resource-efficient water treatment processes, reduced reliance on energy-intensive technologies, and the valorization of industrial byproducts within circular economy frameworks.

Surface energy exchange regulates permafrost stability and cold region climate feedback, yet key thermal parameters governing freeze-thaw transitions remain poorly constrained. In particular, soil emissivity and conductive heat transfer are often treated as static or one-dimensional properties, despite strong phase-dependent changes during freezing and thawing. Here we experimentally resolve the coupled evolution of surface emissivity, thermal conductivity, volumetric heat capacity, and conductive heat flux in sand-, silt-, and clay-dominated soils between -15 °C and 20 °C under varying saturation, organic content, and salinity. Frozen soils exhibit systematically lower emissivity than thawed soils, with distinct nonlinear transitions across phase change. Thermal conductivity increases substantially in the frozen state due to ice-enhanced grain contacts, while latent heat effects generate pronounced peaks in volumetric heat capacity near 0 °C. By explicitly quantifying both vertical and lateral conductive components, we demonstrate that neglecting lateral heat flux can underestimate total conductive energy transfer by up to 31.65%. These results provide physically constrained, phase-resolved parameterizations for land-surface and permafrost models and reduce uncertainty in infrared surface temperature retrievals across thermodynamically sensitive temperature ranges. Our findings establish a mechanistic framework linking phase change, radiative properties, and multidimensional heat transfer in cold region soils.

This study investigates the influence of climate variables, specifically temperature and relative humidity, on the equilibrium moisture content (EMC) of wood—a critical quality parameter. Using data from 100 synoptic stations across Iran (1987–2019), we analyzed trends in temperature, humidity, and EMC through the Mann-Kendall and Sen’s slope methods. Future projections (2020–2049) employed CMIP6 models—CanESM5, CanESM5-CanOE, CNRM-CM6-1, CNRM-ESM2-1, and IPSL-CM6A-LR—under SSP scenarios, with model selection based on RMSE, Scatter Index, and R². Scenarios SSP1-2.6, SSP2-4.5, and SSP5-8.5 were used to project future climatic conditions and corresponding EMC values. The CanESM5-CanOE model exhibits the lowest monthly relative humidity estimation errors in Iran, with errors ranging from 10.1% to 15.0% across different climate zones. Increasing EMC is most frequent under SSP1-2.6 (20%-92% of stations) and SSP5-8.5 (34%-100%). Decreasing trends are significant under SSP2-6.5 (66%-100%) and SSP5-8.5 (45%-88%). Monthly variations: -4.74% to + 3.71%; seasonal: -2.87% to + 2.45%; annual: -1.17% to + 1.00%. Significantly decreasing EMC trends are under SSP2-6.5, increasing trends under SSP5-8.5. Over a 30-year span, EMC varied from 0.06 to 0.62% in winter, from − 1.14 to -1.23% in spring, from − 0.84 to -0.89% in summer, and from − 0.80 to -1.34% in autumn, with most changes being statistically significant. These findings suggest climate change will substantially impact on wood EMC, underscoring the importance of revising future EMC standards accordingly.

Abstract Raman spectra of charcoal provide structural information that enables the reconstruction of past combustion conditions. We present a calibration method (532 nm laser excitation) for determining charring temperatures from Raman spectra of amorphous carbon, based on Raman band intensity ratios (HD/HG). Using a pine wood reference dataset, we establish statistical criteria for estimating temperature, identifying sp²-hybridization clustering, and detecting oxidative weathering. To ensure reproducibility and accessibility, we introduce our tool CHARM as a free, automated webpage ( https://olivierbrcknr.github.io/charm/ ) for processing Raman data—including de-noising, baseline correction, parameter extraction, and temperature reconstruction. This tool generates standardized numerical and graphical outputs that drastically reduce processing time and analytical bias. Applications to archaeological ceramics demonstrate that reliable temperature estimates of blackened surfaces can be achieved without destructive sampling, while tests on thin section preparations confirm that Raman parameters remain unaffected. Furthermore, our protocol enables statistical analysis of charcoals from volcanological contexts, revealing interpretable temperature ranges despite charcoal modifications by oxidative weathering. Our calibration provides a robust method for consistent, rapid temperature reconstruction of amorphous carbon across archaeological, volcanological, and related fields.

Abstract Mud dragons (Kinorhyncha) are an understudied phylum of microscopic marine invertebrates inhabiting a wide range of marine sediments, from shallow coastal habitats to abyssal depths, and occurring from tropical to polar regions. Despite their broad distribution, their minute size often makes them difficult to study. Consequently, molecular resources for the group remain extremely limited and only three complete mitogenomes have been published from this phylum to date. To help fill this substantial gap in genetic data, we sequenced and annotated two new complete mitogenomes from the family Pycnophyidae, Pycnophyes greenlandicus Higgins & Kristensen, 1988 and Cristaphyes cryopygus (Higgins & Kristensen, 1988). Obtained mtDNA sequences were compared with available transcriptomic data from other Kinorhyncha species, providing a more comprehensive basis for the phylogenetic analysis of the phylum. The results showcased unexpected rearrangements in the gene order across all examined taxa, an unusual cox1 –tRNA-Glu genes overlap and an unstable phylogenetic position within the Pycnophyidae family. These new sequences not only significantly expand the mitogenomic data available for Kinorhyncha, but also provide an important step toward a better understanding of phylogenetic relationships within the phylum.

Polycyclic aromatic hydrocarbons (PAHs) in industrial effluents pose severe environmental and health risks due to their carcinogenicity, bioaccumulation potential, and resistance to conventional treatment. This study investigated the effects of nitric acid functionalization and metal ion-exchange on the structural properties and anthracene adsorption performance of activated carbon (AC) and carbon black (CB) as representative carbon-based adsorbents. Nitric acid treatment of CB enhanced mesopore development and introduced oxygen-containing functional groups, improving anthracene removal efficiency from 69 to 74% at a 200:1 feed-to-carbon ratio. Conversely, acid treatment of AC reduced removal efficiency from 60 to 50%, attributed to critical micropore volume effected as confirmed by Brunauer–Emmett–Teller (BET) surface area. Metal ion-exchange reduced adsorption performance in both materials, due to nanoparticle agglomeration and surface area while CB-Ni and CB-Zn retained moderate removal efficiencies of 62% and 66%, consistent with better metal dispersion. A strong linear correlation (R2 = 0.9483) between BET surface area and anthracene uptake in ion-exchanged samples confirmed physisorption via van der Waals interactions as the dominant removal mechanism in the absence of surface functional groups. The optimal adsorbent, CB-2N, maintained stable removal efficiency of 70–74.5% over five consecutive regeneration cycles, demonstrating excellent structural durability and reusability. These findings establish rational design principles for carbon adsorbent selection and functionalization in industrial PAH remediation applications.

As among the most destructive types of natural hazards, geological disasters pose serious threats to human life, property safety, and socioeconomic development. Accurate identification and assessment of geological disaster risk are crucial for revealing the spatial distribution and underlying mechanisms of disasters and for providing scientific support for regional disaster prevention and territorial spatial planning. However, traditional risk assessment methods often suffer from high subjectivity in weight determination, limited model precision, and insufficient coupling among influencing factors, making it difficult to capture the complexity of disaster risk. To address these limitations, in this study, a coupled random forest–assumption of extreme rainfall–analytic hierarchy process (RF–ARE–AHP) model based on slope units for county-level geological disaster risk assessment was developed, using Ningyuan County in Hunan Province, China, as a case study. Model performance was validated using the area under the ROC curve (AUC), confusion matrix parameters, and field investigation results, and a high-resolution risk zoning map was generated at the slope-unit scale. The results show that the susceptibility model achieved an AUC of 0.92, with true positive, true negative, and overall accuracy rates exceeding 85% and false rates below 15%, indicating high model reliability and discriminative capacity. The hazard of geological disasters increased significantly with increasing rainfall intensity, expanding both the spatial extent and the severity of high-hazard areas. In the exposure assessment, the introduction of a damping coefficient effectively differentiated the exposure levels of the threatened elements. The medium–high-risk zones were concentrated mainly in Jiuyi Mountain, Mianhuaping, and Tongmulou Yao ethnic townships, which is consistent with field observations. Overall, the proposed RF–ARE–AHP model reduces subjectivity and enhances accuracy, providing a robust and scalable approach for county-level geological disaster risk evaluation and disaster prevention planning.

Abstract Indoor air pollution, especially in pharmaceutical laboratories, poses significant health risks due to the presence of volatile organic compounds (VOCs) such as benzene, toluene, acetophenone, and benzaldehyde. This study evaluates the efficiency of air phytoremediation technology using four ornamental plant species, Cordyline fruticosa , Syngonium podophyllum , Epipremnum aureum and Chlorophytum comosum to improve Indoor Air Quality (IAQ) by acting as Plant-Based Bio-Filters (PBBFs) in both pot-based and green wall configurations. VOC concentrations were monitored in a real pharmaceutical organic laboratory. Morphological and physiological plant traits including total chlorophyll content, relative water content (RWC), leaf pH, ascorbic acid concentration, stomatal density, and cuticle wax content were evaluated. Air Pollution Tolerance Index (APTI) and dust-capturing potential were calculated to assess the resilience and effectiveness of each species under VOCs exposure. Chemometric tools Principal Component Analysis (PCA) and Orthogonal Projections to Latent Structures-Discriminant Analysis (OPLS-DA) were applied to identify species with superior removal efficiency and to explore the relationship between plant traits and VOC uptake. Among the studied species, Cordyline fruticosa demonstrated the highest removal efficiency for VOCs (87.50%), CO (88.23%), and CO₂ (36.78%), as well as the highest APTI (14.76%), stomatal density (94.34 stomata/mm 2 ), and chlorophyll content. Syngonium podophyllum also showed up to 100% removal of particulate matter (PM 2.5 and PM 10 ) and performed effectively in CO (70.58%) and CO₂ (31.27%) reduction. Multivariate analysis confirmed that plants with higher physiological resilience and morphological surface complexity had significantly greater phytoremediation capacity. This study demonstrate the potential of PBBFs, especially using Cordyline fruticosa and Syngonium podophyllum , as a viable, cost-effective, and sustainable approach to mitigate indoor VOCs and improve air quality in pharmaceutical labs. The findings support integrating ornamental plants into indoor environment as a natural solution for IAQ management.