Concentration Distribution Patterns Research Articles

Dynamic patterns of particulate matter concentration and size distribution in urban street canyons: insights into diurnal and short-term seasonal variations

Dynamic patterns of particulate matter concentration and size distribution in urban street canyons: insights into diurnal and short-term seasonal variations

Investigation of organic content and microbial characteristics distribution at the pretreatment units for wastewater treatment plant sustainable upgrading

It is necessary and significant to acquire the influent characteristics in the whole pretreatment units of the activated sludge process in wastewater treatment plants (WWTPs) for the sustainable upgrading. In this work, we drawn the samples and continuously investigated all the structure units of the pretreatment section in a typical wastewater treatment plant including the anaerobic and aerobiotic treatment processes. We monitored the routine environmental parameters in the water, including dissolved oxygen (DO), pH, and suspended solids (SS). At the same time, we investigated the concentration distribution patterns of chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) and found that the degradation of organic matter in the sewage continued in the pretreatment section. And the remarkable decreasing tendency of organic pollution concentration was confirmed along the flow direction in the pretreatment section, suggesting a modest depletion effect on influent organic matter of the pretreatment process. Moreover, to further validate the degradation process of organic compounds in the preprocessing procedure, analysis and detection were conducted on the types of organic compounds and the microbial community structures in the water samples collected at various sampling points through three-dimensional fluorescent spectroscopy and high-throughput sequencing, respectively. Conclusively, the detailed and accurate influent characteristics can support the scientific basis for the WWTP sustainable operation, management, and upgrading, especially for that with the low C/N ratio influent.

Spatial and temporal distribution characteristics of dust concentration based on satellite in mining area.

The spatial and temporal distribution patterns of dust concentration in the Pingshuo mining area and urban area were analyzed utilizing satellite data. The results indicate that the correlation coefficients of the average PM2.5 and PM10 concentration retrieved by satellite in Shuozhou City are 0.88 and 0.63, respectively, and the satellite inversion data demonstrate high reliability. The spatial distribution of dust concentration in the Pingshuo Mine area is elevated during winter and spring, with significant dust accumulation in winter. The pollution phenomenon in the Pingshuo mining area was pronounced from January to March, and the air quality deteriorated significantly. The correlation analysis of dust concentration between the city and the mining area reveals a marked spatial discontinuity at the boundary between the city and the mining area, indicating that the mining area is not the primary cause of the increase of dust concentration in the urban area, and changes in dust concentration within the mining area exert no significant impact on the urban area. The research results possess significant implications for dust control in both the mining and urban areas.

Low Residents’ Satisfaction with Wetland Leisure Demand in Typical Urban Areas of the Semi-Arid Region in Western China: Spatial Variations and Their Causes

Wetlands, as a crucial component of urban green spaces, provide important leisure services for residents. Construction of wetlands has increased with the rapid urban expansion and population growth in China over recent decades, especially in semi-arid regions with scarce water resources. However, the residents’ satisfaction with wetland leisure demand remains unclear. This study evaluated the residents’ satisfaction with wetland leisure demand by a framework of physical calculation, taking Yinchuan City, the capital city of Ningxia Hui Autonomous Region, in the semi-arid region of Western China as a case study area. Spatial variations in residents’ satisfaction and their causes were revealed by a supply–demand relationship between the population capacity of wetlands and the total population of communities under a framework of physical calculation. The results indicated that 4.22% of the study area, which covered 7.38% of the total population, was fully satisfied with wetland leisure demand. Residents’ satisfaction in the urban area as a whole is low at 0.49, with a concentric distribution pattern increasing as the distance from the central urban area increases. The high population density and scanty wetlands mainly induced a relative-low residents’ satisfaction in the central urban area, accounting for 12.02% of the area and 32.70% of the population. Meanwhile, a relative-high residents’ satisfaction in the outer ring of the central urban area accounting for 59.10% of the area and 20.63% of the population was primarily due to the adequate capacity of wetlands. Medium residents’ satisfaction was mainly attributed to the road network density, which partially transferred local wetland leisure demand to adjacent areas. Wetland constructions and internal structural optimization to improve the capacity for leisure in densely populated central urban areas could provide a feasible path to alleviate unbalanced conditions. These results could deepen the understanding of supply–demand dynamics in the wetland leisure service and provide valuable information for optimizing wetland allocation in urban construction in semi-arid regions.

MHD flow of blood-based hybrid nanofluid through a stenosed artery with thermal radiation effect

The MHD flow of a blood-based hybrid nanofluid with thermal radiation and stenosis effects is explored in this study. Gold (Au) and Copper (Cu) hybrid nanoparticles are assumed to be distributed in the blood. Relevant governing equations are established and appropriately normalized. The Caputo fractional-order derivative is used to convert the transient terms of normalized equations into time-fractional forms, which are then semi-analytically solved using the Laplace transform method to yield complex forms of modified Bessel functions. The concentrated matrix exponential (CME) approach is used to numerically determine approximate inverse Laplace transforms of the updated equations. The distribution patterns of velocity, temperature, and concentration are evaluated graphically. The results showed that the fractional-order derivative and the height of stenosis greatly influence the velocity, temperature and concentration profiles. We also observed that both velocity and temperature decreased with increasing values of Ha. Temperature rises with increasing values of the thermal radiation parameter (Ra) and the Eckert number (Ec) whilst concentration is enhanced with rising values of the chemical reaction parameter (Cr) and the Schmidt number (Sc). Our numerical results show that relevant parameters have considerable influences on skin friction, Nusselt number, and Sherwood number, which are important for understanding blood mobility, heat and mass transfer dynamics, and treating cardiovascular illnesses. Our results are also essential for controlling blood flow, temperature and delivery of drugs to diseased arteries in the human body.

Seawater intrusion-triggered high fluoride groundwater development on the eastern coast of China.

High-fluoride groundwater is commonly found in coastal areas worldwide, while its formation mechanism remains elusive. Herein, a comprehensive study was performed to identify the major controlling factor of high-fluoride groundwater occurrence along the eastern coast of China. Hydrogeochemical methods were employed to examine the distribution patterns of seawater intrusion and fluoride concentration and the impact of seawater intrusion on the fluoride concentration. The results indicate that seawater intrusion significantly influences the groundwater evolution process in the study areas. The groundwater in Laizhou Bay was affected by brine, and the groundwater in Tianjin and Jiangsu was affected by seawater with a mixing ratio lower than 40% and 20%, respectively. And the fluoride concentration in groundwater from Tianjin, Laizhou Bay, and Jiangsu generally exceeded 1mg/L, with the average of 2.3mg/L, 24.9mg/L, and 34.6mg/L, respectively. Both the degree of seawater intrusion and the fluoride concentration exhibit a consistent pattern: Laizhou Bay > Tianjin > Jiangsu. Cl- concentration in groundwater varies positively with the F- concentration (y = 0.66x - 1.31). Moreover, the spatial distribution of areas with high-fluoride groundwater mirrors that of seawater intrusion. The high-fluoride groundwater varies spatially and is related to the degree, stage, and type of seawater intrusion. In other words, when seawater intrusion intensifies more or groundwater in the freshwater renewal phase with higher Na+/Ca2+ or the presence of paleo-seawater intrusion with higher fluoride concentration of brine, the concentration of fluoride in groundwater is higher. As seawater intrusion intensifies, the high-fluoride groundwater in the study areas generally poses a higher health risk to human. These findings enhance our comprehension of the mechanisms underpinning high-fluoride groundwater in coastal regions and the environmental ramifications of seawater intrusion.

Evaluation of Zinc Concentrations in Fruit from Various Pear Strains and Cultivars in China for Establishing a Standard for Zinc-Enriched Pears

Zinc (Zn)-enriched pears, which are derived from genetically related cultivars or crops fortified using agronomic methods, have the potential to partly satisfy the human demand for Zn nutrition and diversify consumer choices. However, a standard for the Zn fortification level in pears is lacking, and the disparity in literature-reported fruit Zn concentrations can vary by substantial amounts. Before investigating the Zn concentrations in fruits of the main pear cultivars in China, common sample preparation methods were compared. Among the pre-treatment methods tested, the freeze-dry technique had a greater degree of discrete variation, whereas oven drying (fresh weight) was the optimal method for determining fruit Zn concentrations. Based on the optimal method, no significant distribution patterns of fruit Zn concentration were found among the regions and strains examined. The averaged pulp Zn concentration in all 26 cultivars was 0.72 mg kg−1, with the Hongxiangsu, Jinfeng, and 420 cultivars having the highest concentrations. Combined with the findings from our previous field experiments on Zn-fortified pears, a Zn concentration of ≥0.90 mg kg−1 is the suggested standard for pear enrichment. These results help us to better understand pear Zn nutrition levels and facilitate the marketisation of the fortified fruit.

The Distribution Characteristics and Ecological Risks of Alkylphenols and the Relationships between Alkylphenols and Different Types of Land Use.

In this study, the spatial distribution characteristics of nine alkylphenols (APs) in the Yongding River and Beiyun River were analyzed. The differences in the concentrations and spatial distribution patterns of nine APs were systematically evaluated using principal component analysis (PCA). The relationships between the concentration distribution patterns and the risks associated with nine APs were investigated under various categories of land use conditions in the region. The results demonstrated that the APs were widely present in both rivers, and the pollution risks associated with the APs were more severe in the Yongding River than in the Beiyun River. The results show that the contamination risks associated with 4-NP were the most serious in the two rivers, with detection percentages of 100% and 96.3%, respectively. In the Yongding River, the APs showed a tendency of low concentration levels in the upper reaches and high levels in the middle and lower regions. Meanwhile, the overall concentration levels of the APs in the Beiyun River were relatively high. However, despite the differences between the upper and middle regions of the Yongding River, the distribution pattern of the APs in the Beiyun River was basically stable. The concentration levels and risk quotient of the APs were negatively correlated with the vegetation cover land use type and positively correlated with the cropland and unused land use types within 500 m, 1 km, and 2 km. The purpose of this study was to provide theoretical data support and a basis for AP pollution risk evaluations in the Yongding River and Beiyun River.

Three-dimensional spatial interpolation for chlorophyll-a and its application in the Bohai Sea

Assessing the health of coastal ecosystems is crucial for maintaining ecological balance. One significant indicator of water eutrophication is the distribution of chlorophyll-a (Chl-a), which makes obtaining a complete three-dimensional spatial distribution of Chl-a essential for assessment. This study utilized the linear radial basis function (RBF-Linear) method to obtain a comprehensive and reasonable spatial distribution of Chl-a. The method was applied to obtain the three-dimensional spatial field of Chl-a concentration in the Bohai Sea in March, May, August, and October from 2016 to 2018. The distribution pattern of Chl-a concentration in the Bohai Sea displayed characteristic spatial and temporal variations. Spatially, high Chl-a concentration was most concentrated in coastal waters, particularly in estuaries and mariculture areas. Temporally, there were two peaks in March and August. The total Chl-a and areas with high Chl-a concentration in four sub-regions of the Bohai Sea were also calculated to enable a comprehensive assessment of the marine ecological environment. By analyzing the temporal and spatial variation of Chl-a in the Bohai Sea and evaluating the marine ecological environment, we confirmed the feasibility and rationality of RBF-Linear. Our findings have the potential to contribute to improve the accuracy of ecological models and assessment of the satellite products.

Quantitative visualization of a radioactive plume with harmonizing gamma-ray imaging spectrometry and real-time atmospheric dispersion simulation based on 3D wind observation

ABSTRACT To propose a novel monitoring method for the quantitative visualization of 3D distribution of a radioactive plume in the vicinity of release point and source term estimation of released radionuclides, the feasibility of its analysis method is demonstrated by preliminary test. The proposed method is the combination of gamma-ray imaging spectroscopy with the electron tracking Compton camera (ETCC) and real-time high-resolution atmospheric dispersion simulation based on 3D wind observation with Doppler lidar. ETCC can acquire the angle distribution images of direct gamma-ray from a specific radionuclide in a target radioactive plume by quantitatively capturing gamma-ray incidence angles and spectrum distributions. The 3D distribution of each radionuclide in the radioactive plume is inversely reconstructed from direct gamma-ray images of each radionuclide by several ETCCs located around the target by harmonizing with the air concentration distribution pattern of the plume predicted by real-time atmospheric dispersion simulation. A prototype of the analysis method was developed, showing a sufficient performance in several test cases using hypothetical data generated by numerical simulations of atmospheric dispersion and radiation transport. The proposed method is expected to become an innovative monitoring framework for nuclear emergency.

Using a Remote-Sensing-Based Piecewise Retrieval Algorithm to Map Chlorophyll-a Concentration in a Highland River System

Chlorophyll-a(chl-a) has been used as an important indicator of water quality. Great efforts have been invested to develop remote-sensing-based chl-a retrieval models. However, due to the spatial difference in chl-a concentration, a single model usually cannot accurately predict the whole range of chl-a concentration. To test the performance of precedent chl-a models, we carried out an experiment along the upper and middle reaches of the Kaidu River and around some small ponds in the Bayanbulak Wetland. We measured water surface reflectance in the field and analyzed the chl-a concentration in the laboratory. Initially, we performed a sensitivity analysis of the spectrum band to chl-a concentration with the aim of identifying the most suitable bands for various chl-a models. We found that the water samples could be divided into two groups with a threshold of 4.50 mg/m3. Then, we tested the performance of 11 precedent chl-a retrieval models and 7 spectral index-based regression models from this study for all the sample datasets and the two separate datasets with relatively high and low chl-a concentrations. Through a complete comparison of the performance of these models, we selected the D3B model for water bodies with high chl-a concentration and OC2 model (ocean color 2) for low chl-a concentration waters, resulting in the hierarchical and piecewise retrieval algorithm OC2-D3B. The chl-a concentration of 4.50 mg/m3 corresponded to the D3B value of −0.051; therefore, we used −0.051 as the threshold value of the OC2-D3B model. The result of the OC2-D3B model showed a better performance than the other algorithms. Finally, we mapped the spatial distribution and seasonal pattern of chl-a concentration in Bayanbulak Wetland using Sentinel-2 images from 2016 to 2019. The results indicated that the chl-a concentration in the riparian ponds was generally in the range of 8–10 mg/m3, which was higher than that in rivers with a range of 2–4 mg/m3. The highest chl-a concentration usually appears in summer, followed by spring and autumn, and the lowest in winter. The correlation between meteorological data and chl-a concentration showed that temperature is the dominant factor for chl-a concentration changes. Our analytical framework could provide a better way to accurately map the spatial distribution of chl-a concentration in complex river systems.

Distribution and source apportionment of toxic and trace elements in some benthic and pelagic coastal fish species in Karnaphuli River Estuary, Bangladesh: Risk to human health.

The Karnaphuli River is one of the prime and most important streams in the southeastern part of Bangladesh. The favorable water current and the geographic location have rendered the Karnaphuly River estuary a suitable habitat and a breeding ground for diverse fish species. Reversely, this estuary has been polluted by discharges from many point and non-point sources due to its location in the catchment area of a heavily industrialized area, Chattagram port city. However, published research concerning the status of toxic and trace elements in some commercially important benthic and pelagic coastal fish species in Karnaphuli River estuary was not found in the existing literature. Therefore, it's an important field of study on the assessment of toxic and trace elements concentration in the commercially important benthic and pelagic coastal fish species and their health taxation in the Karnaphuli River Estuary. Energy dispersive X-ray fluorescence (ED-XRF) was used to quantify trace metal concentration in edible parts of the fish species. This study revealed that the rank of the trace metals concentration was as follows (mg/kg): Zn (37.1)>Mn (16.12)>V (11.16)>Cu (9.49)>Rb (5.62)>Pb (2.98)>Cr (1.59)>Co (1.17). The F-test showed that a significant difference at 95% confidence level in the distribution pattern of trace metals concentration among the examined fish species in the study area. The metal pollution index (MPI) in the muscle of fishes were found to be in the following order: L. bata>P. monodon>T. cirratus>M. bleekeri>O. pabda>H. nehereus>L. calcarifer>P. argenteus>P. paradiseus>T. toli, and the MPIs for most of the benthic fish species were higher compared to the pelagic fishes. On the other hand, the examined fish species were significantly bio-accumulative with the highest bio-accumulation factor value for benthic species. The multivariate analysis identified that the sources of the trace metals were associated with anthropogenic activities. For the human health risk assessment concern, estimated daily intake, target hazard quotient and cancer-causing risk were estimated. The results for non-cancer hazardous index values were found to be lower than unity. On the other hand, the total cancer risk data ranging from 1.24E-05 to 1.70E-05 were fallen within the range for the threshold values (1.0E-06 to 1.0E-04). However, considering the suggested values set by the environmental and regulatory agencies, it has been recommended that no significant non-carcinogenic and cancer-causing health risk for humans was seen due to the consumption of the studied fish species.

Alteration and mineralization patterns in orogenic gold deposits: Constraints from deposit observation and thermodynamic modeling

Hydrothermal alteration and mineralization types of orogenic gold deposits display many variations depending on formation depths, types of host rock, compositions of ore fluids, spatial positions, fluid/rock ratios, and repetitive modifications during multiple fluid infiltrations in the complicated processes of fluid-rock interaction. Therefore, establishing holistic reference patterns of hydrothermal alteration with associated mineralization for the orogenic gold system is necessary. Based on the observation of typical orogenic gold deposits and thermodynamic simulation of fluid-rock reaction, the general features of proposed patterns include:(1)Orogenic ore fluids are capable of transporting sufficient gold from deep (5 kbar and 600°C) to shallow (1 kbar and 200°C) crustal levels, resulting in alteration and mineralization occurred in a much-varied depth. Only considering the effects of fluid-rock reaction and sulfidation, the formation of pyrrhotite and pyrite at relatively high and low P-T conditions, respectively, is the most important mechanism driving gold precipitation. In addition, the changes of fluid fO2 and pH can also trigger a decrease in the gold solubility in fluids.(2)Multiple waves of fluid infiltration are capable of dissolving the early-formedulfides and gold, and reprecipitate them in the distal alteration zones, which can explain the irregular gold concentration distribution patterns in wide alteration zones. The fluids under higher P-T conditions (5 kbar and 600°C and 3 kbar and 400°C) are more capable of dissolving early-formed sulfides and gold. Additionally, the later infiltrated fluids can transform early-formed pyrrhotite into pyrite.(3)The model of interactions between ore fluids and aluminosilicate rocks at varied P-T conditions indicates that the alteration mineral assemblages in hypozonal deposits (>12 km) mainly include biotite, amphibole, anorthite, K-feldspar, quartz, and pyrrhotite assemblages; that those in mesozonal deposits (6 to 12 km) are characterized by chlorite, calcite, quartz, muscovite, pyrite or pyrrhotite. The epizonal deposits (<6 km) commonly develop more abundant Fe-Mg bearing carbonates (e.g., dolomite, ankerite, and siderite), quartz, muscovite, and pyrite. The compositional variations of ore fluids and host rocks have important controls on the development of iron-oxides and carbonaceous material.(4) The alteration halo is relatively restricted under hypozonal to lower mesozonal conditions. However, broad carbonation develops under upper mesozonal to epizonal conditions, with Fe-Mg bearing carbonates and calcite distributed in proximal and distal zones, respectively.

Contamination and Potential Ecology Risk of Heavy Metals in the Sediment of the Cau river, Vietnam

Five sediment cores collected at the Cau river section flowing through Thai Nguyen were analyzed to evaluate the vertical profile, enrichments, and contamination of six heavy metals including Cu, Pb, Zn, Cr, As, and Cd. The impacts of investigated metals on ecology were estimated by the toxic unit and the potential ecological risk index. The obtained mean heavy metal concentration in the five sediment cores for investigated metals was: Cd (0.56 - 1.74 mg kg−1) &lt; As (10.2 - 32.3 mg kg−1) &lt; Cr (12.1 - 36.2 mg kg−1) &lt; Cu (16.0 - 51.2 mg kg−1) &lt; Pb (24.5 - 85.5 mg kg−1) &lt; Zn (48.2 - 151 mg kg−1). The spatial distribution and vertical patterns of heavy metal concentration in the sediment cores differed substantially among the investigated sites. Among the six investigated heavy metals, Cr was of natural origin while the remaining 5 metals (Cu, Pb, Zn, As, Cd) came primarily from human activities. Based on the classification using EF, Igeo, and PLI, sediment at S3, where there was a concentration of discharge from main activities of the area, was strongly contaminated with heavy metals. The other sites (S1, S2, S4, and S5) were in the condition slightly contaminated with heavy metals. As and Cd were mostly associated to the overall pollution load index of heavy metals in the sediment of the Cau river. The highest STU and considerable risk from heavy metals were observed at S3. Sediment at S1, S2, S4, and S5 posed a moderate ecological risk.

Study on sediment erosion of high head Francis turbine runner in Minjiang River basin

The Wenchuan earthquake greatly reduced the forest water conservation capacity along the banks of Minjiang River. With the intensified soil erosion and the rapid increasing sediment transport, the sediment erosion of hydraulic turbines running on the river has become more and more serious, especially of high head Francis turbines. In this study, the k-ε multiphase flow turbulence model was used to calculate the sediment-water flow of a high head Francis turbine with long and short blades in Minjiang River. The distribution pattern of sediment concentration (sediment volume fraction) on the blade surface shows that the sediment particles mainly gather on the outlet edge at 10% of the blade height on the suction surface of the long blade, while the sediment concentration on the surface of the short blade is small. The erosion of the 0Cr13Ni5Mo runner blade was tested by the flow around erosion method, and the erosion amount on the blade surface in the severe erosion area was obtained. Based on the test data of erosion and the numerical calculation results of sediment flow, a formula to calculate the sediment erosion rate of flow passage components with 0Cr13Ni5Mo material was given for turbines operating in Minjiang River. By using this formula, the sediment erosion of flow passage components in hydraulic turbines with 0Cr13Ni5Mo or similar materials operating in Minjiang River can be predicted.

The difference in air pollutants in typical northern and southern CHINA coastal cities-Taking Shenzhen and Qingdao as examples

In 2018, four air pollutants in Qingdao and Shenzhen were comprehensively analyzed and evaluated according to the standards. According to the results, PM2.5 exceeded its standard by multiples of 1.11 and 1.03 in January and February, respectively, in Shenzhen, and the no-exceedance probability was 84.6%. However, the no-exceedance probability in Qingdao was only 50%. When the maximun index of ambient air quality was used to evaluate the above pollutants, the air pollutant in Shenzhen was NO2 from May to September and PM2.5 in other the months, but the pollutants in Qingdao were different each month. The distribution patterns of the monthly average mass concentration of the pollutants in Shenzhen and Qingdao were consistent with the seasonal distribution. The particulate matter in the air was still the focus of the government in Shenzhen. The sources of air pollutants in Qingdao were diverse, and most pollutants were related to energy combustion.

Qualitative Analysis of Modified Advanced-Platelet-Rich Fibrin Buffy Coat among Diabetic Patients and Tobacco Smokers with Chronic Periodontitis: A Cell Block Cytology Study.

Aim:The aim of this study was to evaluate and compare histologically the pattern of distribution of platelet and leukocyte concentration, quality of fibrin network, and the aggregation of platelets in the three zones of modified advanced platelet-rich fibrin (A-PRF) buffy coat among uncontrolled type 2 diabetic patients, tobacco smokers, and healthy individuals with chronic periodontitis.Materials and Methods:In this cross-sectional cytology study, 180 generalized chronic periodontitis patients (46–55 years) were enrolled – Group 1 (control group): 60 systemically healthy participants, Group 2 (test group): 60 heavy tobacco smokers, and Group 3 (test group): 60 uncontrolled type 2 diabetic patients. Fifteen milliliters of blood was drawn from all study participants. Modified A- PRF membrane was prepared and then processed histologically.Results:The distribution pattern of platelet and leukocyte concentration in modified (A-PRF) gradually declines from the serum to the red blood cell (RBC) end of a clot in all groups. We have assessed that the serum and middle end of modified (A-PRF) membrane had an increasingly moderate distribution of platelets and leukocytes in both type 2 diabetics and tobacco smokers. RBC end had more of sparse distribution in all the three groups. Healthy individuals exhibited 95% of reversible pattern, whereas tobacco smokers had 78.33% and uncontrolled type 2 diabetic patients had 93.33% of irreversible aggregation pattern of platelets. Loose fibrin network pattern was seen in all the three groups. These observations conclude that tobacco smokers had a high percentage of loose fibrin network with sparse distribution of cells. Males showed more loose fibrin network pattern of modified (A-PRF) membrane than compared to females.Conclusion:In the present study, it can be concluded that the application of modified (A-PRF) may provide enhanced periodontal healing in uncontrolled type 2 diabetic patients and tobacco smokers; furthermore, females may have better regenerative capacity compared to males.

Spatial distribution based on optimal interpolation techniques and assessment of contamination risk for toxic metals in the surface soil

The condition of the soil environment is critical for human health and agricultural sustainability. As a result, the environmental and ecological issues impacting the soils throughout the world are receiving more attention. This research focuses on local site-specific studies in Cerrito Blanco, Matehuala municipality, San Luis Potosi, Mexico, and describes different types of GIS interpolation techniques, multivariate statistical analysis, and various contamination indices to investigate the relationship between predictive accuracy, levels of contamination risk, and soil toxic metal elements variation. Inductively coupled plasma optical emission spectroscopy (ICP-EOS) used to test 39 digested surface soil samples for significant toxic metals (Ag, Cd, Co, Cr, Li, and Ni) after suitable dilution with deionised water. According to the results, we found that only the mean value of cadmium (Cd) exceeded the permissible standard value. After evaluating the four types of interpolation techniques, the Inverse Distance Weighting (IDW) was determined to be the optimal interpolation model for assessing the spatial distribution patterns of toxic metal concentration in the research area. The calculated contamination risk indices showed no significant high contamination risk due to soil-borne toxic metals. These results provide a comprehensive analysis of the impact of past mining activities on toxic metal concentrations in non-cultivated surface soil.

Inverse model investigation of radionuclide dispersion in a ventilated room based on the adjoint probability method

The improved identification of radioactive pollutant leakage points in ventilated rooms is one of the key technologies for nuclear accident consequence assessment. Radionuclides disperse turbulently in ventilated rooms, and leakage locations lead to different concentration distribution patterns. Considering the effects of radioactive decay and deposition, an inverse model of radionuclide dispersion under ventilation conditions was established based on the adjoint probability method coupled with computational fluid dynamics (CFD). The airflow field was calculated by CFD, and the probability of leakage locations for the radioactive source was estimated by the adjoint probability method coupled with CFD. The results showed that the proposed model could help nuclear emergency decision-makers accurately trace the location of leakage sources and provide more scientific information for early emergency response and consequence assessment.

Features of the distribution of molecular hydrogen in groundwater in various geological and tectonic conditions of Uzbekistan

As a result of generalization and analysis of previously performed work on the determination of hydrogen on the day surface, a picture of the distribution of hydrogen concentration in the aeration zone was obtained. The increased concentration of hydrogen on the day surface and in the aeration, zone is associated with the most favourable conditions for the transit of fluids from the folded Palaeozoic basement to the surface cover (upper part of the Earth’s crust). These zones are zones of active fluid conductivity, which leads to a high concentration of hydrogen on the day surface. Intense linear anomalies are confined to the zone of intersection of the Tuzkoy-Rometan transverse fault with the Bukhara-Gissar regional fault, with which seismic events are associated (epicentres Gazli earthquakes occurred 08.04.1976, 17.05.1976 and 19.03.1984). Analysis of long-term observations of gas composition on an example of molecular hydrogen in groundwater southwestern part Karzhantaus fault, covering the territory of Tashkent city and its surroundings, obtained hydrogen concentration distribution pattern area. A different concentration of hydrogen in the fault zone was revealed, associated with the heterogeneity of the geological and structural structure.