Accumulation Process Research Articles

The Impact of Exogenous Organic Matter on the Properties of Humus Compounds of Soils Developing on a Reclaimed Fly Ash Landfill

Fly ash does not contain organic matter to initiate soil-forming processes and the proper development of plant cover. Therefore, in the reclamation of fly ash landfills, an integrated approach is required, including the introduction of exogenous organic matter into the top layer of ash. This study assessed changes in the content and quality of organic matter in soils developing on a reclaimed fly ash landfill. This study included reclaimed areas without the introduction of EOM (RV_1—the direct introduction of plants) and with the introduction of EOM (RV_2—surface humus and RV_3—sewage sludge). In samples taken 15 years after reclamation, the contents of total organic carbon (TOC) and total nitrogen (TN), the fractional composition of organic matter, the susceptibility of organic matter to oxidation, and soil carbon management indices (carbon pool index (CPI), C lability (L), lability index (LI), and carbon management index (CMI)) were determined. The study results showed that the use of EOM in the reclamation of the ash dump significantly increased the content and improved the quality parameters of organic matter and thus influenced the initiation of the process of organic matter accumulation. In RV_1 soil, the accumulation of carbon resources was only found in the topsoil. An increase in carbon resources in the 15–40 cm layer was only noted in the variants in which EOM was introduced (RV_2 and RV_3). Carbon management indices showed that organic matter transformations covered only the top layers of these soils and were closely related to the EOM inflow. The interdependence of the CPI and L was most beneficial in the soil reclaimed with sewage sludge. In the soil of this reclaiming variant, the CMI had a value above 100, which indicates the initiation of the soil-forming process. Significant differences between the assessed reclamation variants were confirmed by means of PCA based on organic matter quality indicators. The organic matter content and quality indicators were the most favorable in the soil of variant RV_3. The obtained results confirmed that the introduction of EOM into the top layer of fly ash has a beneficial effect on the accumulation and quality indicators of organic matter and thus on the development of the soil-forming process in Technosols developing on a reclaimed fly ash landfill.

Reservoir Regulation Changed Terrestrial Particulate Organic Carbon Transport and Burial Processes off the Yellow River Mouth

AbstractThe dynamic behavior of particulate organic carbon (POC) is crucial for understanding biogeochemical carbon cycling in coastal and oceanic environments. However, intense watershed human activities have significantly altered the POC transport and burial in the estuary‐coast continuum. Here, we developed a novel parameterization scheme that incorporates grain‐size constraints to investigate the dispersal and accumulation processes of POC off the Yellow River mouth during the water‐sediment regulation scheme (WSRS) using a three‐dimensional hydrodynamic model (FVCOM). The result shows that the model successfully captures the offshore transport and hydrodynamic sorting of POC, which leads to a progressive increase in POC content with offshore dispersion and significant variations in POC and sediment deposition across different isobaths. Rapid fluctuations in river discharge and sediment composition during WSRS stages result in noticeable differences in sedimentation patterns for sediment and POC. At the Water‐regulation stage, distinct differences are observed in the distribution of riverine POC and sediment across various isobaths. In contrast, during the Sediment‐regulation stage, these differences are significantly reduced due to the finer riverine sediment. Compared to the sediment‐regulation, the Water‐regulation plays a crucial role in enhancing the effective burial of POC. Coarse‐grained sediment can form an armored layer that protects OC from disturbance. Additionally, increased runoff during this stage promotes the offshore transport of POC to a less energetic environment (>10 m in depth). This study provides valuable insights into POC dynamics in high‐turbidity estuarine and coastal environments. It underscores the importance of employing comprehensive modeling approaches to elucidate these complex processes.

Heavy metals in roadside soil along an expressway connecting two megacities in China: Accumulation characteristics, sources and influencing factors

Transportation is widely recognized as a significant contributor to heavy metal (HM) pollution in roadside soils. A better understanding of HM pollution in soils near expressways is crucial, particularly given the rapid expansion of expressway transportation in China in recent years. In this study, 329 roadside topsoil samples were collected along the Beijing-Tianjin Expressway, which connects two megacities in China. Chemical analysis showed that HM concentrations in the soil samples were generally below national limits. The mean pollution index (Pi) values for As, Cr, Cu, Ni, Pb, and Zn ranged from 0.94 to 1.01, while Cd and Hg exhibited slightly higher mean Pi values of 1.19 and 1.13, respectively. The Nemerow integrated pollution index values for all samples ranged from 0.71 to 4.97, with a mean of 1.26. This suggests a slight enrichment of HM above natural background levels, especially for Cd and Hg. Source apportionment using positive matrix factorization revealed that natural sources contributed the most to soil HMs (64.51 %), followed by agricultural sources (19.15 %), traffic sources (9.77 %), and industrial sources (6.57 %). The Shapley additive explanation analysis, based on the random forest model, identified soil organic carbon, deep soil HM content, altitude, total soil K2O, urbanization composite impact index, and total soil P as primary influencing factors. This indicates that the impact of transportation on roadside soils along the Beijing-Tianjin Expressway is currently relatively limited. The prominent influence of soil properties and altitude underscored the importance of “transport” and “receptor” in the soil HMs accumulation process at the local scale. These findings provide critical data and a scientific basis for decision-makers to develop policies for expressway design and roadside soil protection.

Porcine transient receptor potential channel 1 promotes adipogenesis and lipid deposition

Adipose tissue, an important organ involved in energy metabolism and endocrine, is closely related to animal meat quality and human health. Transient receptor potential channel 1 (TRPC1), an ion transporter, is adipocytes’ major Ca2+ entry channel. However, its function in fat deposition is poorly understood, particularly in pigs, which are both an ideal model for human obesity research and a primary meat source for human diets. In the present investigation, our findings demonstrate a prominent expression of TRPC1 within the adipose tissue of pigs with a strong fat deposition ability. Functional analysis showed that TRPC1 promotes primary preadipocyte proliferation and adipogenic differentiation. In vivo, transgenic mice expressing porcine TRPC1 (Tg-pTRPC1) exhibited aggravated high-fat diet-induced obesity, hepatic steatosis, and insulin resistance. Moreover, TRPC1 may facilitate adipogenesis via activating PI3K/AKT and β-catenin signaling pathways. Our research underscores the pivotal role of porcine TRPC1 as a positive regulator in adipogenesis and lipid accumulation processes, providing a potential target for improving animal meat quality and treating obesity-related diseases in humans.

Dynamic nexus between urban digitization and pollutant discharge: RBC theory and empirical evidence from China

An economy undergoing digitalization may experience environmental degradation. This study aims to explore the potential environmental consequences of digitalization. First, the paper develops a real business cycle model that incorporates pollution constraints and endogenous digital capital investment. Second, the study identifies three stages of endogenous digital capital accumulation: resource mismatch, scaling, technology spillovers, and eventual monopolization. Correspondingly, environmental changes unfold in three stages: degradation, subsequent improvement, and regression back to deterioration. Finally, the empirical analysis draws on the process of digital capital accumulation across Chinese cities, revealing that while digital capital accumulation initially contributed to environmental degradation, technology spillovers could help mitigate these effects. Furthermore, the study highlights the differing levels of digital capital across cities, placing them at various stages of development. It underscores the critical need for policymakers to carefully balance the scale of digital capital, as both insufficient and excessive accumulation can exacerbate environmental challenges. This analysis offers valuable insights for policymakers seeking to foster digital development while mitigating environmental pollution.

Digital Platform, Spatial-Digital Fix, and the Reconfiguration of Apparel Production Networks

Digital Platform, Spatial-Digital Fix, and the Reconfiguration of Apparel Production Networks

Characteristics of Mudflow Distribution and Evolution of Mudflow Fan in Erlian Village

Debris flow in the upper Yellow River is very developed and is generally characterized by wide distribution with large numbers and a high frequency of occurrence. This paper analyses the distribution characteristics, material composition, and formation causes of the Erlian debris flow fan in the eastern part of the Guide Basin and discusses the relationship between debris flow fan and river evolution. Results show that: (1) At least 66 debris flow gullies and 20 large debris flow accumulation fans have been developed on both sides of the Yellow River in the eastern Guide Basin. (2) In the Erlian Village area, the Yellow River channel has experienced the accumulation, erosion, destruction, and accumulation process of debris flow fans in 16 kaB.P., 16 ka B.P.–8 ka B.P., and 8 kaB.P., respectively, the late-accumulation fan has been continuously extruding the Yellow River channel since 8 kaB.P., and the Yellow River channel has been shifted to the south by at least 1.25 km during the period of 8 ka. (3) Five accumulation periods for the Late Mudslide Fan were identified by classifying the 16 kaB.P. and 8 kaB.P. early and late mudslide fans. This study can provide theoretical and technical support for preventing debris flow disasters in the upper reaches of the Yellow River and has certain reference and reference values.

To the selection of battery parameters for a M1 category hybrid vehicle

Background: To optimize the operation of a hybrid vehicle power plant, it is necessary to correctly select the parameters of its traction battery, which significantly affect the control algorithm and charge-discharge balance. The presence of a methodology that allows one to make a reasonable choice depending on the characteristics of the target vehicle, the conditions and modes of its operation will make it possible to increase energy efficiency indicators.Aims: The work aim was to develop a methodology for calculating the parameters of a hybrid vehicle traction battery using the energy charge-discharge balance of its power plant.Matherials and methods: A mathematical model of the charge-discharge energy balance has been proposed. Using this model, it is possible to make appropriate calculations on the amount of energy expended by the power plant when a vehicle moving through the stages of the European urban cycle, and analyze various algorithms for controlling it to achieve maximum energy efficiency, as well as select capacity and pover of traction battery. The basis for the calculations was the cycle described in UN Regulation No. 83.Results: The process of energy accumulation in a traction battery is considered, and criteria for choosing an algorithm for the operation of the vehicle’s power plant are indicated. The energy of vehicle movement in the urban cycle was determined, taking into account the operating time of the units, and the charge-discharge energy balance was calculated, which, in turn, made it possible to find the proper battery capacity. It has been established that the battery charge value at the end of the cycle should be equal to the initial value, which allows the use of a lower capacity battery and ensure maximum energy efficiency of the power plant. Also, based on the calculation results, recommendations were made regarding the optimization of the specific energy and weight-size parameters of the battery.Conclusions: The proposed methodology allows for a reasonable choice of а hybrid vehicle power plant parameters to ensure its energy efficiency.

Estimating forest litter fuel load by integrating remotely sensed foliage phenology and modeled litter decomposition

Litter on the forest floor, or from a fire perspective the litter fuel load (LFL), is a key driver of the occurrence and spread of surface fires and an important regulator of forest fire behavior. High-quality spatiotemporal LFL data are essential for modeling fire behavior and assessing fire risk in forest ecosystems. Traditionally, LFL is estimated from ground-based measurements, but they are difficult to implement on large spatial scales. While remote sensing techniques have the advantage of large-scale observation, they encounter challenges in retrieving LFL because forest canopies generally block signals from the forest floor. Here we present a new method based on modeled litter accumulation to estimate LFL dynamics, integrating litterfall influx from the forest canopy and decomposition outflux through a mass balance approach. Annual litterfall was estimated based on seasonal changes in foliage fuel load which are retrieved from Landsat imagery and a radiative transfer model, while the decomposition rate was derived from meteorological data. Litterfall and decomposition were quantified over the past 20 years with the difference between the two being LFL accumulating over time. We validated the estimated LFL using 105 ground-based measurements in Liangshan Yi Autonomous Prefecture, China, and this validation demonstrated a reasonably strong performance for estimating LFL (R2 = 0.67, root mean squared error (RMSE) = 2.56 Mg ha−1, relative RMSE = 31.61 %). Our method integrates remote sensing-based foliage phenology with the ecological process of LFL accumulation, enabling large-scale LFL monitoring for forest fire risk assessments.

Origin, Migration, and Accumulation of Crude Oils in the Chaoyang Step-Fault Zone, Fushan Depression, Beibuwan Basin: Insight from Geochemical Evidence and Basin Modeling

The Fushan Depression is a hydrocarbon-rich depression in the Beibuwan Basin, South China Sea. In this study, 14 source rocks and 19 crude oils from the Chaoyang Step-Fault Zone and Southern Slope Zone were geochemically analyzed to determine their origins. The hydrocarbon generation, migration, and accumulation processes were also determined using two-dimensional basin modeling. Crude oils from the low-step area show a close relationship with the source rocks of the first and second members of the Eocene Liushagang Formation (Els1 and Els2). The oils from the middle-step area and the Southern Slope Zone are derived from the local source rocks in those areas, in the third member of the Eocene Liushagang Formation (Els3). Hydrocarbons generated from the Els3 source rocks of the Southern Slope Zone migrated along sand bodies to the Els3 reservoir. The fault system of the Chaoyang Step-Fault Zone controls hydrocarbon migration and accumulation in the low-step and middle-step areas. The resource potential of the middle-step area is limited by its shallow burial depth. The low-step area is a more favorable exploration area due to its proximity to the source kitchen.

Tendon Cell Biology: Effect of Mechanical Loading.

Tendons play a crucial role in the musculoskeletal system, connecting muscles to bones and enabling efficient force transfer. However, they are prone to acute and chronic injuries, which, if not properly repaired, can significantly impair function. Tendinopathy, a prevalent condition affecting approximately 20% of musculoskeletal complaints, arises from an imbalance between micro-injury accumulation and repair processes. The extracellular matrix (ECM) of tendons is a hierarchical structure comprising collagen fibrils, proteoglycans, and glycoproteins that regulate organization, hydration, and mechanical properties. Mechanotransduction pathways, mediated by integrins and focal adhesion complexes, activate signaling cascades such as MAPK/ERK and PI3K/Akt, driving tenocyte gene expression and ECM remodeling. Adaptations to load involve region-specific remodeling, with tensile regions favoring aligned Type I collagen and compressive regions promoting proteoglycans like aggrecan. Stress shielding or reduced loading disrupts these pathways, leading to matrix disorganization and inflammation, predisposing tendons to degenerative changes. Insights into these molecular mechanisms inform rehabilitation strategies to enhance tendon repair and mitigate tendinopathy progression in both athletic and general populations.

Productivity of Biocenosis Plants and Humus Accumulation Processes in Eroded Meadow-Chernozem Soils

In long-term experiments, the content of humus in natural and agroecosystems on meadow-chernozem soils depended on the species diversity of plants, the state of the vegetation cover, the cultivation of the arable horizon and its erosion. During the 10-year observation period, the humus content in arable soil decreased by 4.5% relative to the initial state, while under meadow grasses, on the contrary, it increased by 22%. Then, during the 20-year accounting period, the processes of humus accumulation in the cultivated soil changed little. Among natural ecosystems, humus accumulation processes were most active in the humus-accumulative (A) and transitional horizons (AB) under the aspen forest. The reserves of humus and nutrients in eroded soils decreased dramatically, causing a decrease in the productivity of meadow grasses. It has been established that for a significant accumulation of humus (up to 8%) in the non-eroded soil of the 100-year period of ecosystem functioning, it is necessary to combine incoming carbon in the form of forest litter and roots with the biomass of perennial meadow grasses.

Backwater rise upstream of a stream-crossing culvert due to large wood accumulation and sediment deposition

Stream-crossing culverts (SCCs) are widely used transportation facilities in mountain streams. The sediment or large wood (LW) transported by the flow may block the SCC, resulting in a water level rise to increase the flood risk. Until now, the coupled impacts of sediment supply and LW accumulation on the backwater rise upstream of SCCs have remained unclear, which greatly restricts the flood control in streams with SCCs. In this study, a series of flume experiments were conducted to investigate the coupled impacts of sediment supply and LW accumulation on the backwater rise upstream of an SCC. The experimental results showed that: 1) the process of LW accumulation at the SCC has three stages: culvert blockage, triangle formation, and LW carpet; 2) the water level upstream of the SCC increases with increasing LW volume added to the flume in the culvert blockage and triangle formation stages, whereas it is almost unaffected by LW volume in the LW carpet stage; 3) the backwater height and length upstream of the SCC increases with the increase in the sediment supply rate under the combined effects of LW accumulation and sediment deposition, and the LW volumes corresponding to the LW carpet stage at the SCC are greater than those without sediment supply. Finally, predictors are proposed for the backwater height and length upstream of the SCC owing to the sediment supply and LW accumulation.

Rhizosphere as a hotspot for microbial necromass deposition into the soil carbon pool

Abstract Microbial leftovers, known as necromass, are key players in storing carbon in the soil around plant roots (i.e. rhizosphere), a zone characterized by high‐efficiency microbial anabolism. Yet, the extent and mechanisms through which the rhizosphere contributes to soil organic carbon (SOC) via microbial necromass, especially under changing environments remain unclear. We aimed to evaluate the contributions of microbial necromass to SOC and influencing factors from the rhizosphere perspective. We collected the rhizosphere and bulk soil from 39 alpine coniferous forest sites on the eastern Tibetan Plateau to assess the extent of microbial necromass contribution to SOC in the rhizosphere from a dynamic perspective by calculating the ratio of increased amino sugars (AS) to increased SOC in the rhizosphere relative to that in bulk soil (RAS/SOC). We also collected climate data and determined nutrient concentrations and microbial physiological traits in rhizosphere soil to elucidate the factors affecting RAS/SOC. The results showed that across all sampling sites, the average concentrations of SOC‐normalized AS in the rhizosphere were significantly higher than those in the bulk soil. Furthermore, the average RAS/SOC was greater than 1, indicating a faster microbial necromass accumulation than SOC accumulation in the rhizosphere. These results implied that the rhizosphere sustains a greater capacity for microbial necromass contribution to the SOC pool than the bulk soil does. Soil nutrient availability was the primary factor affecting RAS/SOC, and precipitation indirectly affected microbial anabolism and RAS/SOC by changing soil nutrient status. Additionally, with increasing rhizosphere soil nutrient availability, microbial carbon‐use efficiency and growth rate increased but the biomass‐specific enzyme activity declined, indicating that microorganisms tended to exhibit high‐yield strategies with increasing soil nutrient availability. Synthesis. Our findings underpin the vital effect of microbial necromass in SOC accumulation from the rhizosphere perspective and offer valuable insights into mechanisms underlying microbial C metabolic processes in rhizosphere SOC accumulation under changing environments.

Arkypallidal neurons in the external globus pallidus can mediate inhibitory control by altering competition in the striatum

Reactive inhibitory control is crucial for survival. Traditionally, this control in mammals was attributed solely to the hyperdirect pathway, with cortical control signals flowing unidirectionally from the subthalamic nucleus (STN) to basal ganglia output regions. Yet recent findings have put this model into question, suggesting that the STN is assisted in stopping actions through ascending control signals to the striatum mediated by the external globus pallidus (GPe). Here, we investigate this suggestion by harnessing a biologically constrained spiking model of the cortico-basal ganglia-thalamic (CBGT) circuit that includes pallidostriatal pathways originating from arkypallidal neurons. Through a series of experiments probing the interaction between three critical inhibitory nodes (the STN, arkypallidal cells, and indirect pathway spiny projection neurons), we find that the GPe acts as a critical mediator of both ascending and descending inhibitory signals in the CBGT circuit. In particular, pallidostriatal pathways regulate this process by weakening the direct pathway dominance of the evidence accumulation process driving decisions, which increases the relative suppressive influence of the indirect pathway on basal ganglia output. These findings delineate how pallidostriatal pathways can facilitate action cancellation by managing the bidirectional flow of information within CBGT circuits.

Sustainable Nitrogen Management in Rice Farming: Spatial Patterns of Nitrogen Availability and Implications for Community-Level Practices

Sustainable nitrogen management is crucial for long-term food security and environmental protection in rice farming systems. However, the spatial patterns of nitrogen availability at the community level remain poorly understood, hindering the development of effective sustainable management strategies. This study introduces a novel application of spatial autoregressive analysis to investigate available nitrogen distribution in paddy soils across a rice farming community in Kyoto, Japan. Soil samples from 61 plots, including organically farmed ones, were analyzed for available nitrogen and various physicochemical properties. Contrary to the hypothesis of high variability between adjacent plots, significant positive spatial autocorrelation in available nitrogen was observed, revealing previously unrecognized community-level patterns. The spatial Durbin model outperformed traditional regression approaches and revealed complex spatial interactions in soil properties. Water-soluble organic carbon and humus content showed strong but opposing effects, with a positive direct impact but negative spatial interaction, suggesting topography-driven accumulation processes. Water-soluble nitrogen exhibited reverse patterns with negative direct effects but positive spatial interaction, indicating potential nutrient transport through water movement. These findings highlight the importance of considering both direct and indirect spatial effects in understanding soil fertility patterns, challenging the conventional plot-by-plot management approach. This methodological advancement provides new perspectives for more effective, community-scale soil management strategies in rice farming systems. Moreover, it demonstrates an innovative approach to maximizing the value of outsourced soil analysis data, providing a model for more comprehensive utilization of such data in agricultural research. By enabling more targeted and efficient nitrogen management practices that consider both plot-level processes and landscape-scale interactions, this study potentially contributes to the development of more sustainable and resilient rice production systems.

Predicting Natural Gas Production in Various Nations Using a Fractional Grey Bernoulli Approach

Accurate forecasting of natural gas production is crucial for economic stability, environmental sustainability, and market investment. This study presents an advanced forecasting method using the fractional grey Bernoulli model, which combines fractional accumulation and Bernoulli processes to enhance the predictive accuracy for nonlinear datasets. The model’s versatility and flexibility allow it to adapt to various data characteristics and complexities, thereby outperforming traditional grey models in forecasting performance. To optimize the model parameters, this study employs the Particle Swarm Optimization (PSO) algorithm, further improving the model’s effectiveness. Empirical analysis of natural gas production data from Brazil, Italy, and Qatar demonstrates that the model exhibits significant advantages in both fitting and forecasting capabilities. The findings indicate that the fractional grey Bernoulli model achieves high accuracy and reliability in predicting natural gas production in these countries, providing a robust framework for strategic energy planning and investment decision-making. With average forecast errors of 1.9113%, 4.0353%, and 1.8902% for natural gas production in Brazil, Italy, and Qatar respectively, this study underscores the model’s effectiveness in enhancing forecast reliability and minimizing risk, providing valuable insights for sustainable energy development.

Appropriate water and nitrogen supply regulates the dynamics of nitrogen translocation and thereby enhancing the accumulation of nitrogen in maize grains

To improve nitrogen uptake and grain quality in maize, this study explores the dynamic processes of nitrogen accumulation, distribution, and translocation under varying water and nitrogen supplies, aiming to optimize water-nitrogen management practices. Field trials were conducted in Karamay, Xinjiang, in 2022 and 2023, with different irrigation levels (75 % ETc, 100 % ETc, 125 % ETc) and nitrogen application rates (0, 93, 186, 279 kg Nhm−2). The effects of water and nitrogen supply on nitrogen accumulation and distribution in aboveground maize organs were analyzed, and the dynamic characteristics of maize nitrogen accumulation were examined using the characteristic parameters of the Richards nitrogen accumulation equation. The results showed that beyond the W2N2 treatment (irrigation at 100 % ETc and nitrogen application of 186 kg N hm−2), increases in irrigation and nitrogen did not significantly enhance nitrogen accumulation per plant. Under W2N2, high levels of nitrogen were accumulated in maize leaf, stem, bract, cob, and grain. The nitrogen transfer among different organs and their contribution to grain nitrogen showed the following hierarchy: leaf > stem > cob > bract, with the contribution rates to grain nitrogen ranging from 26.16 % to 56.23 % over the two years. The Richards model accurately quantified the dynamic relationship between water-nitrogen supply and crop nitrogen accumulation, with the coefficient of determination (R²) ranging from 0.9864 to 0.9999 and the normalized root mean square error (NRMSE) from 0.70 % to 6.51 %. Optimal water-nitrogen supply significantly reduced the accumulated temperature required for maize to enter the rapid nitrogen accumulation phase and achieve maximum growth rates, while extending the duration of the rapid growth phase and increasing both the maximum growth rate and the average growth rate during this period. Grain nitrogen accumulation was positively correlated with nitrogen accumulation rates, as well as nitrogen accumulation and translocation in various organs. Under suitable irrigation and nitrogen application, the interactive effects of water and nitrogen (W × N) significantly increased both nitrogen accumulation and nitrogen accumulation rates, laying a foundation for nitrogen translocation to grains in the late growth stages and enhancing grain nitrogen accumulation. Thus, appropriate water and nitrogen supply can significantly influence nitrogen accumulation, distribution, and translocation processes in maize, regulating grain nitrogen accumulation. This study provides valuable information for nitrogen accumulation regulation and grain quality improvement in maize in Xinjiang and other regions with similar climatic conditions.

Numerical Simulation of the Coal Measure Gas Accumulation Process in Well Z-7 in Qinshui Basin

The process of coal measure gas accumulation is relatively complex, involving multiple physicochemical processes such as migration, adsorption, desorption, and seepage of multiphase fluids (e.g., methane and water) in coal measure strata. This process is constrained by multiple factors, including geological structure, reservoir physical properties, fluid pressure, and temperature. This study used Well Z-7 in the Qinshui Basin as the research object as well as numerical simulations to reveal the processes of methane generation, migration, accumulation, and dissipation in the geological history. The results indicate that the gas content of the reservoir was basically zero in the early stage (before 25 Ma), and the gas content peaks all appeared after the peak of hydrocarbon generation (after 208 Ma). During the peak gas generation stage, the gas content increased sharply in the early stages. In the later stage, because of the pressurization of the hydrocarbon generation, the caprock broke through and was lost, and the gas content decreased in a zigzag manner. The reservoirs in the middle and upper parts of the coal measure were easily charged, which was consistent with the upward trend of diffusion and dissipation and had a certain relationship with the cumulative breakout and seepage dissipation. The gas contents of coal, shale, and tight sandstone reservoirs were positively correlated with the mature hydrocarbon generation of organic matter in coal seams, with the differences between different reservoirs gradually narrowing over time.

Static headspace-gas chromatography with mass spectrometry for the assessment of the bioaccumulation of volatile organic compounds associated with microplastics in animal tissues

BackgroundThe excessive increase in the production of plastics worldwide and their mismanagement have turned these materials into a threat to the environment and living organisms. Plastics undergo erosion and degradation processes releasing additives, monomers of their formulation, and even generating one of the most worrying emerging pollutants: microplastics. These contaminants have been found in both aquatic and terrestrial ecosystems, so it is clear the need to develop a methodology to determine the accumulation of these pollutants and their associated compounds in living organisms. ResultsThis work presents a new combination of static headspace with gas chromatography coupled to mass spectrometry (SHS-GC-MS) for the determination of volatile organic compounds (VOCs) associated with microplastic materials in animal tissue samples. A total of 48 samples were analysed, corresponding to different organs (brain, heart, fat, liver, muscle, lung, kidney) of lamb, pig, rabbit, turkey, chicken, and beef, and 60 VOCs related to the presence of plastics were tentatively identified. Moreover, the identity of 25 VOCs was confirmed and they were also quantified, with contents in the 1.12–920 ng g−1 range. The application of chemometric tools allowed to evaluate the relationship between the type of animal organ and the presence of contaminants associated with microplastics, showing a tendency towards a greater accumulation in kidney and liver. Verification of the origin of the VOCs found was carried out by means of a thermogravimetric analysis - mass spectrometry study. SignificanceThe developed analytical approach generates useful and valuable information to better understand the exposure pathways of microplastics and their associated compounds, as well as the related migration and accumulation processes may happen in animal organs. This methodology has demonstrated high sensitivity, precision, robustness, and automation, as well as minimal sample handling.