Spatiotemporal distribution of soil heavy metals and source-specific probabilistic risk assessment in arid gold mining cluster areas of northwest China.

ABSTRACT Investigating the geochemical behavior of trace elements in coal under high-temperature conditions not only enables the reconstruction of their geochemical characteristics during thermal evolution but also holds great significance for the prevention and control of coal-derived pollution and the resource utilization of high-value-added elements. This study takes the No. 6 coal seam of the Guanbanwusu Mine in the Jungar Coalfield as the research object. Based on thermal simulation experiments at approximately 500°C, combined with sequential chemical extraction and multiple analytical methods, the modes of occurrence, migration, and enrichment of trace elements during thermal simulation are revealed. The results show that among 48 trace elements, except for Sr, U, and As, the concentration coefficients of the remaining elements in partings are higher than those in raw coal. In raw coal, 23 elements, including Li, Ga, Sr, Zr, In, Pb, Th, U, most rare earth elements and yttrium (REY), have contents higher than the average values for Chinese coals, warranting focused investigation. As the thermal simulation temperature increases, moisture and volatile matter decrease significantly, while ash yield increases. The trace element contents in semicoke show an increasing trend, indicating that trace elements do not readily migrate with gaseous and liquid products but are more likely to remain in the semicoke. Sequential chemical extraction reveals that in raw coal, most trace elements are primarily present in the silicate fraction, followed by carbonate and organic-bonded fractions. With increasing temperature, the proportion of organic-bonded trace elements in semicoke increases, while the proportion of silicate fractions decreases, which is attributed to enhanced complexation and physical encapsulation within the organic matrix. At each thermal simulation temperature, elements with mobility above the average are classified as highly mobile, whereas those below the average are considered weakly mobile. A comparison of relative migration capacities shows that Pb, Y, Li, Zr, Pr, Th, Tm, Er, Gd, Ga, and La exhibit stronger migration ability than the average, while Lu, Dy, Ho, Yb, Nd, Tb, Ce, In, Sm, U, Sr, and Eu exhibit weaker migration ability than the average. The migration process of elements is jointly influenced by temperature, raw coal properties, thermal stability of minerals, and modes of occurrence.

Advancing the efficient and comprehensive control of volatile organic compounds (VOCs) is a critical cornerstone for establishing global atmospheric pollution prevention systems and achieving long-term improvements in air quality. Although catalytic oxidation is an effective technology for VOCs removal, its practical application is often limited by catalyst sintering and poor low-temperature activity. This study investigates the grain refinement and surface defect engineering of Cu-doped Mn3O4 spinel catalysts derived from metal-organic frameworks (MOFs) for low-temperature toluene oxidation. By controllably introducing Cu, crystal growth is effectively suppressed, and lattice distortion is induced, thereby increasing the density of surface defects. The optimized Cu0.03Mn2.97O4 sample exhibits enhanced surface oxygen mobility and modified cation distribution, promoting efficient oxygen activation and redox cycling, which significantly improves low-temperature catalytic activity, achieving a T90 value of 215 °C. Simultaneously, when the Cu0.03Mn2.97O4 catalyst was loaded onto porous Al2O3 ceramic, the gas diffusion efficiency was improved, and the agglomeration of the powder catalyst was effectively inhibited. The obtained Cu0.03Mn2.97O4/C catalyst reached T90 at 210 °C and maintained excellent stability during the toluene degradation test under 3 vol.% water vapor conditions for 50 consecutive hours. By integrating defect engineering with macroscopic structural design, this work elucidates the intrinsic structure-activity relationship, offering a practical strategy for doping engineering of transition metal oxide catalysts and their integration onto porous ceramic supports.

Heavy metal(loid) pollution in watersheds surrounding mining areas originates from multiple and complex sources, posing persistent threats to terrestrial-aquatic ecosystems and human dietary safety. This study systematically investigated the pollution characteristics, spatial distribution, ecological risks and human health hazards of seven typical heavy metal(loid)s (As, Pb, Cr, Cd, Cu, Zn, and Ni) in the integrated water-soil-vegetable continuum of a mining-affected watershed in Southwest China. Field sampling was carried out in three functional zones with different mining disturbance intensities, and inductively coupled plasma mass spectrometry (ICP-MS) was used to detect heavy metal(loid) concentrations in all samples. Multiple pollution evaluation indices and the USEPA human health risk assessment model were adopted for comprehensive quantitative analysis. The results showed that 44.0% of surface water samples exceeded national permissible limits, with high-pollution areas concentrated in intensive mining zones, presenting moderate overall aquatic heavy metal(loid) pollution. Although the average concentrations of seven heavy metal(loid)s in riparian soils complied with Chinese agricultural soil screening standards, localized significant enrichment was observed for As (1.98 times), Cd (4.62 times), Cu (1.81 times), and Zn (2.72 times) compared with regional background values, causing mild comprehensive soil pollution. Farmland soils exhibited prominent Cu and Zn accumulation, and leafy vegetables in the study area suffered severe Pb and Cd pollution, with potential dietary exposure risks. Health risk assessment indicated that children face higher non-carcinogenic and carcinogenic risks than adults via soil hand-to-mouth exposure; dietary intake of vegetables leads to moderate carcinogenic risks for children caused by As and Ni exposure. Overall, this study clarifies the migration and enrichment rules of heavy metal(loid)s in the water-soil-vegetable system of mining watersheds, confirms the prominent ecological and human health risks of Cd, As and Pb in the study area, and provides targeted basic data for regional heavy metal(loid) pollution prevention and food safety management.

Fine particulate matter with a diameter ≤2.5 μm (PM2.5) pollution poses a global public health crisis, demonstrating significant threats to human health. This study focused on the strategically important Chengdu-Chongqing Economic Circle in western China, systematically comparing the toxic effects of urban and rural PM2.5 across five levels. PMF and regression analysis were used to identify source contributions, dual-omics to pinpoint key molecules, and epidemiological data with a GAM model to assess health risks. Findings demonstrate that rural PM2.5 possesses greater biotoxicity than its urban counterpart. Cytotoxicity in urban and rural PM2.5 originated from road dust/vehicle emissions and biomass burning, respectively. Subsequently, integrated omics and molecular biology analyses identify kinesin family member 20A (KIF20A) as a shared key target, which mediates toxicity induced by both urban and rural PM2.5. Finally, epidemiological analysis reveals that females and ≥65 years old exhibit relatively high sensitivity to urban PM2.5 exposure trends, with rhinitis showing a comparatively higher impact among various related diseases. The novelty of this work lies in its pioneering application of a multi-tiered investigative approach. This approach spans "environmental samples-cellular mechanisms-population health" within the Chengdu-Chongqing economic circle context, systematically elucidating common and distinct respiratory health risk of urban and rural PM2.5. This work offers a vital scientific foundation for advancing region-specific, precise air pollution prevention and control measures.

Spatial planning plays a pivotal role in shaping the health and well-being of urban populations. Since 2016, most Chinese cities have incorporated health-related elements into their Territorial Spatial Planning (TSP) 2035 Schemes as part of national healthy city initiatives. It is essential to examine how health is represented in these statutory planning documents and whether the level of attention varies across cities. We developed an analytical framework for healthy city planning by synthesizing international scholarly literature and governmental policy documents. Using this framework, the TSP 2035 Schemes of 36 major Chinese cities were examined through a mixed-method design combining thematic dimension analysis, keyword network analysis, and disparity measures. All 36 cities have placed healthy city development on their planning schemes, focusing primarily on eight dimensions: (1) green and open space, (2) climate change and disaster response, (3) physical education (PE) facilities and public services, (4) environmental pollution prevention and control, (5) medical and health services, (6) elderly dimension, (7) health equity, and (8) healthy travel. Of these dimensions, green and open space along with climate change and disaster response receive the most emphasis. Notable healthy city keywords include 'park', 'green space', 'healthcare', 'livability', 'sports', 'resilience', 'pollution control', 'disaster prevention', 'walking', and 'jogging'. Cross-city comparisons reveal substantial disparities: cities with higher administrative status generally articulated more extensive and more diverse health-related planning content, whereas many lower-tier cities pay relatively little attention to equity-sensitive dimensions. Health has become a visible component of statutory planning discourse in China, but its integration remains selective and uneven across cities. The results suggest that China's healthy city development has reached an intermediate stage of "health promotion and education", and in terms of health-spatial planning integration, China has moved beyond a narrow environmental health orientation, yet important gaps remain in equity-sensitive and people-centered dimensions. Recommendations include strengthening legislation to support healthy city planning, improving the openness and transparency of TSP 2035 Schemes, and more differentiated policy support across cities.

Source apportionment of photochemical losses of VOCs and ozone formation potential during the critical ozone pollution period of 29 cities in the North China Plain.

In the context of the interplay between ecology, society, and economy, analyzing the characteristics of soil heavy metal pollution and constructing ecological security patterns have emerged as critical scientific issues that necessitate urgent attention for the advancement of high-quality agricultural development. This study focused on the farmland surrounding the Baiyun Mountain mining area in Nanyang, China, and involved the collection of 437 surface soil samples (0–20 cm) to analyze the spatial differentiation characteristics of nine heavy metal elements, including Ag, Cu, and Pb. An ecological risk assessment model was developed to evaluate the ecological risks posed by potentially toxic elements in the region, based on the theory of matter element extension. Additionally, the Positive Matrix Factorization (PMF) model was employed to analyze the sources of heavy metal pollutants. The results indicated that: (1) The average concentrations of Ag, Cu, Pb, Zn, Mo, Sb, Ba, As, and Hg were 0.06, 17.50, 22.72, 66.84, 1.15, 0.85, 426.39, 9.25, and 0.05 mg·kg-1, respectively, with Zn, Mo, and Hg significantly exceeding the soil background values for Henan Province; (2) The ecological risk assessment of potentially toxic elements revealed that 93.82% of the samples were classified as clean, 5.49% as at mild risk, and 0.69% as at severe risk, with Hg identified as the primary ecological risk factor; (3) The primary sources of pollution can be categorized as follows: natural parent material sources (26.1%), mixed sources from transportation and mining development (25.8%), mixed sources resulting from pesticide use and mining emissions (19.8%), atmospheric deposition from fossil fuel combustion (15.1%), and sources from non-metallic mineral mining and building material industry (13.2%). This study provides a scientific basis for the prevention and control of soil pollution in farmland located in mining areas.

Fluorescence detection of 2,4-dinitrophenol and 2,4,6-trinitrophenol using the 2D benzimidazole-linked covalent organic frameworks.

Advances in sensor arrays for ions: From discrimination to application.

To investigate the characteristics and ecological risk posed by microplastics （MPs） pollution in sewage sludge （SS） across China， a comprehensive analysis was conducted on 252 samples from 36 cities， employing stereomicroscopy， Fourier transform infrared spectroscopy， as well as the pollution load index （PLI）， polymer hazard index （H）， and potential ecological risk index （PERI） model. The MPs abundance in SS ranged from （2.6±0.6）×103 to （232.6±116.1）×103 n·kg-1， with an average value of （35.9±40.1）×103 n·kg-1. The MPs abundance exhibited a descending trend of South > Southwest > East > North > Northwest > Northeast > Central China. The MPs were mainly composed of transparent fibers and shafts of 100-500 μm， with the main polymers being ethylene propylene polymer （PE-PP）， polypropylene （PP）， and polyester （PES）. Based on the total SS production in 2016， the amount of MPs emission was estimated to be 2.17×1014 particles， exhibiting a spatial distribution pattern with a greater amount in eastern China than that in western China. The landfill and land application were the primary destinations for MPs in SS（63.57%）， accounting for 1.38×1014 particles. According to the three ecological risk assessment models， the ecological risk of MPs in SS was at a high-risk level. These findings provided significant data support for the prevention and control of MPs pollution in SS across China.

Groundwater serves as a vital source of domestic and agricultural water in rural areas of the Songnen Plain. Its chemical composition and water quality directly impact public health and regional sustainable development, making them subjects of significant concern. This study employed a comprehensive analytical framework, integrating Piper trilinear diagrams, ionic ratio analysis, the Water Quality Index (WQI), and the Human Health Risk Assessment (HHRA) model, to preliminarily evaluate groundwater conditions in a rural township of the Songnen Plain. The multi-method approach was designed to provide scientific insights for groundwater pollution prevention and remediation strategies in the region. Results indicate that the predominant groundwater chemical type in the study area is HCO3-Ca. The hydrochemical process is primarily controlled by weathering and dissolution of silicate and carbonate minerals, accompanied by cation exchange. The WQI ranged from 84.78 to 192.82, with an average of 132.68, indicating overall moderate water quality. Fe and Mn are significant factors affecting water quality. The potential non-carcinogenic risks posed by groundwater to children, females, and males (0.988, 0.701, 0.534) and carcinogenic risks (1.77 × 10-5, 6.27 × 10-5, 4.81 × 10-5) are both below the USEPA recommended threshold (1.0, 1 × 10-4), indicating that the health risks were generally acceptable, though the HI for children approached the threshold. The results underscore the need for targeted mitigation of elevated Fe/Mn concentration (e.g., via aeration biofilters) while highlighting the region's low health risks under current conditions. This work provides a template for integrating geochemical and health risk paradigms in groundwater management.

Differences in the transformation and sources of atmospheric particulate mercury forms during haze weather processes in inland and coastal metropolises.

Research on heavy metal contamination in agricultural soils developed on granite hilly and slope terrains in China remains relatively limited, despite the widespread distribution of such geomorphological settings. Huayuan County, located in Xiangxi, Hunan Province, is characterized by extensively weathered granite-derived soils, particularly across hilly, sloped, and intensively cultivated landscapes. Taking Huayuan Town as a representative study area, this study systematically investigates the concentration levels, spatial heterogeneity, and sources of heavy metals in agricultural soils of granite hilly slopes by integrating geochemical indices, spatial analysis, and multivariate statistical approaches. The results show that the geo-accumulation indices (Igeo) of all analyzed elements are generally below 0, indicating that the soils are classified as practically uncontaminated. Manganese (Mn) exhibits the highest concentrations, with an average value of 497.18 mg/kg and a wide range from 164.56 to 3252.67 mg/kg. The Igeo values of Mn vary from - 2.09 to 2.21, which is likely associated with the extensive distribution of manganese deposits and the geochemical characteristics of the granite parent material in the region. Spatial distribution analysis reveals that Co, Cr, Cu, Ni, V, Fe, and Hg display broadly similar patterns, suggesting common controlling factors. Multivariate statistical results further demonstrate strong homologous relationships among Co, Fe, V, Ni, Cr, Zn, and Mn, indicating that these elements are predominantly derived from primary minerals in the granite parent rock, such as biotite, amphibole, magnetite, and trace sulfides. By focusing on a typical but underrepresented granite hilly slope agricultural system, this study highlights the element-specific spatial behavior and source characteristics of heavy metals under strong geogenic control and long-term anthropogenic disturbance. The findings provide new empirical evidence for understanding heavy metal accumulation mechanisms in granite-derived soils and offer a scientific basis for soil pollution prevention, agricultural management, and environmentally informed policy formulation in similar geological and geomorphological settings.

Citizen science initiatives and outcomes in plastic pollution monitoring and control in the southern Bay of Biscay.

An efficient long-term daily PM2.5 concentration prediction method based on decomposition-ensemble and recursive error correction: A case study of the Beijing area.

The impact of industrial relocation on urban pollution prevention and control: Insights from heterogeneous policy effects based on machine learning methods

Retraction: Towards sustainable management: Exploring the role of internal monitoring in pollution prevention

Nitrate contamination in groundwater poses a significant threat to drinking water safety and ecological health in rapidly urbanizing regions. Establishing the natural background levels of nitrate in groundwater is essential for effective pollution prevention and for distinguishing anthropogenic impacts from natural conditions. In this study, 166 groundwater samples and 12 isotope samples were collected from Zhuhai City, China. By integrating Cl--NO3-/Cl- ion ratio diagrams with the Grubbs method, we determined and validated the natural background levels of nitrate in groundwater. A qualitative analysis of the driving factors influencing these levels was conducted, and recommendations for groundwater nitrate pollution control were proposed. Results show that the environmental background concentrations of nitrate in the study area range from 1.51 to 57.78 mg/L. Overall, background levels in the porous aquifers of the plain areas are substantially higher than those in the fractured-bedrock aquifers of the hilly areas. In the validation analysis, anomalous samples from Unit S1 exhibit δ15N-NO3- values exceeding 10‰, indicating significant sewage-derived contamination. In contrast, anomalous points in Unit S2 are concentrated in hilly areas and characterized by lower nitrate concentrations, reflecting limited human influence. The reliability of anomaly identification was confirmed through integration of land use patterns with isotopic data. Groundwater nitrate background levels are controlled by a combination of natural and anthropogenic factors. In the plains, organic-rich lacustrine-alluvial silt layers, poor hydrodynamic conditions conducive to solute accumulation, and shallow oxidizing aquifer environments collectively lead to background concentrations far exceeding drinking water standards. In the hilly areas, granite bedrock releases negligible amounts of nitrogen, resulting in inherently low background levels. These findings provide valuable insights for accurately identifying nitrate pollution in groundwater systems within rapidly urbanizing contexts, optimizing nitrogen management strategies, and safeguarding groundwater resources.

Parent compounds and soil properties as primary drivers of neonicotinoid transformation products in surface soils from an intensive agricultural Basin in Central China.