Foliar Uptake and Distribution of Metallic Oxide Nanoparticles in Maize (Zea mays L.) Leaf.

The foliar uptake of Fe3O4, Cr2O3, CuO, and ZnO nanoparticles (NPs) by maize (Zea mays L.) was studied in a lab-scale experiment. The significant increase of Fe concentrations in leaves exposed to Fe3O4 was observed in both stomatal closing and stomatal opening treatments, suggesting the presence of a nonstomatal uptake. In parallel treatments with equal doses of Fe3O4 (∼200 nm), Cr2O3 (∼300 nm), CuO (∼30 nm), and ZnO (∼40 nm) (20-200 µg), the retention percentage of Fe in the leaves (21.0-69.0%) was higher than that of Cr, Cu, and Zn (0.5-14.0%). The steric hindrance effect seems more important for NPs of >200 nm, while hydrophobic surface and negative charge promote the foliar uptake of NPs smaller than 200 nm. The accumulation of NPs in the cuticle was observed through dark-field hyperspectral microscopy. Cr2O3, Fe3O4, and CuO NPs were difficult to penetrate the cuticle. In comparison, ZnO further migrated and distributed within the extracellular space of epidermal and mesophyll cells of the exposed leaf, possibly due to its comparatively higher solubility and hydrophilicity. The findings highlight the potential of the nonstomatal uptake, which might be a critical route for metallic oxide NPs to enter the food chain.

A review of tire wear particles: Occurrence, adverse effects, and control strategies.

Tire wear particles (TWPs), common mixed particulate emerging contaminants in the environment, have global per capita emissions accounting for 0.23-1.9 kg/year, attracting global attention recently due to their wide detection, small size, mobility, and high toxicity. This review focuses on the occurrence characteristics of TWPs in multiple environmental media, adverse effects on organisms, potential toxicity mechanisms, and environmental risk prevention and control strategies of TWPs. The environmental fate of TWPs throughout the entire process is systematically investigated by the bibliometric analysis function of CiteSpace. This review supplements the gap in the joint toxicity and related toxicity mechanisms of TWPs with other environmental pollutants. Based on the risks review of TWPs and their additives, adverse impacts have been found in organisms from aquatic environments, soil, and humans, such as the growth inhibition effect on Chironomus dilutes. A multi-faceted and rationalized prevention and control treatment of "source-process-end" for the whole process can be achieved by regulating the use of studded tires, improving the tire additive formula, growing plants roadside, encouraging micro-degradation, and other methods, which are first reviewed. By addressing the current knowledge gaps and exploring prospects, this study contributes to developing strategies for reducing risks and assessing the fate of TWPs in multiple environmental media.

Identifying and monitoring of abandoned farmland in key agricultural production areas on the Qinghai‒Tibet Plateau: A case study of the Huangshui Basin.

Curbing the continuous abandonment of large areas of farmland is important for meeting the global food demand and promoting agricultural and rural development. Accurate identification is the key to the effective management and utilization of abandoned farmland. The identification of abandoned land based on a long time series of remote sensing data has become rapid and effective. Therefore, a set of training and test datasets generated from invariant samples and reference sample sets is established in this paper. On this basis, the Google Earth Engine (GEE) is used to classify Landsat and Sentinel high-precision long-term remote sensing images from 2000 to 2022. In addition, a change detector based on the sliding window algorithm is proposed to extract abandoned farmland in the Huangshui Basin from 2002 to 2020, and the intensity, trend, frequency, reclamation rate and utilization efficiency are analyzed. The results revealed that the OA of land use classification in the Huangshui Basin from 2000 to 2022 was between 0.852 and 0.91, and the kappa coefficient was between 0.822 and 0.89, indicating a good classification effect. From 2002 to 2020, the accumulated abandoned farmland area in the Huangshui Basin continued to increase, showing a fluctuating upward trend, and the phenomenon of farmland abandonment and reclamation occurs repeatedly in some areas. From the overall distribution, the abandoned area gradually increased from the central region to the southeast. With the passage of time, the amount of abandoned farmland in the valley increased gradually, and the abandoned area was transferred from the high mountains to the valley area. The average annual abandonment rate of supplementary farmland was 50.45%, which was much greater than that of basic farmland. Most of the supplementary farmland could not be effectively and judiciously used, and the utilization efficiency was low. The research results provide data support for the reuse of abandoned farmland in ecologically fragile plateau areas, the formulation of targeted strategies, the implementation of timely adjustments, and the establishment of new ideas and methods for the accurate identification of abandoned farmland.

The Phase Distribution Characteristics and Interphase Mass Transfer Behaviors of the CO2-Water/Saline System under Gathering and Transportation Conditions: Insights on Molecular Dynamics.

In order to investigate the interphase mass transfer and component distribution characteristics of the CO2-water system under micro-scale and nano-scale transport conditions, a micro-scale kinetic model representing interphase mass transfer in the CO2-water/saline system is developed in this paper. The molecular dynamics method is employed to delineate the diffusion and mass transfer processes of the system's components, revealing the extent of the effects of variations in temperature, pressure, and salt ion concentration on interphase mass transfer and component distribution characteristics. The interphase mass transfer process in the CO2-water system under transport conditions can be categorized into three stages: approach, adsorption, and entrance. As the system temperature rises and pressure decreases, the peak density of CO2 molecules at the gas-liquid interface markedly drops, with their aggregation reducing and their diffusion capability enhancing. The specific hydration structures between salt ions and water molecules hinder the entry of CO2 into the aqueous phase. Additionally, as the salt concentration in water increases, the density peak of CO2 molecules at the gas-liquid interface slightly increases, while the density value in the water phase region significantly decreases.

Distribution characteristics, sources and risk assessment of heavy metals in the surface sediments from the largest tributary of the Lancang River in the Tibet Plateau, China.

Angqu, positioned in the eastern expanse of the Tibet Plateau, claims the title of the largest tributary to the Lancang River. In October and December of 2018, in the sediment of Angqu, a comprehensive investigation was conducted on nine heavy metals-arsenic (As), manganese (Mn), chromium (Cr), cadmium (Cd), lead (Pb), mercury (Hg), copper (Cu), zinc (Zn), and nickel (Ni). This investigation aimed to scrutinize the spatial and temporal distribution patterns of these metals, assess the pollution status and ecological risks associated with the sediments, and delve into the sources contributing to their presence. The research results indicate that the average concentrations of As, Hg, and Cd in Angqu sediments exceed the soil background values of Tibet, while the concentrations of other heavy metals are below the soil background values of Tibet. Notably, arsenic poses potential ecological risks. In Angqu sediments, the concentrations of Mn, Cu, Ni, and Pb are generally higher in the wet season, but the seasonal variations of heavy metals in Angqu sediments are not significant. The sediments in the Angqu Basin are predominantly affected by mercury Hg, Cd, and As, with varying degrees of pollution at different sampling points. In the main stream of Angqu (City section), Hg pollution has reached above a moderate level, whereas As pollution near the tributary is only slightly polluted. The analysis of heavy metal sources reveals that there are five primary contributors to heavy metals in surface sediments of Angqu: parent material, agricultural activities, groundwater, atmospheric deposition, and other unidentified sources. Mn, Cr, Pb, and Ni are mainly derived from soil parent material, accounting for more than 50%. About 60.82% of As comes primarily from groundwater. Zn and Cd are mainly sourced from agricultural activities, accounting for 41.25% and 34.33%, respectively. Additionally, 20.6% of Hg originates from atmospheric deposition.

Exploring spatiotemporal distribution characteristics of air quality and driving factors: empirical evidence of 288 cities in China.

Excellent air quality is important for China to achieve high quality economic development. The paper analyses the spatial and temporal distribution characteristics of the air quality index (AQI) in 288 Chinese cities, and further investigates the driving factors affecting air quality using the spatial Durbin model (SDM) based on the panel data of 288 Chinese cities from 2014 to 2021. The results of the study show that: (1) China's air quality level has improved in general, but there are large differences in air quality between regions; (2) China's AQI has significant spatial positive autocorrelation, and the Moran's scatter plot shows a high-high and low-low agglomeration; (3) The driving factors of air quality have different effects, and regional heterogeneity is obvious. Some developed regions in China have already crossed the inflexion point of the environmental Kuznets curve (EKC); promoting industrial upgrading and reducing pollutant emissions can significantly improve urban PM2.5 concentrations; and the "Three-Year Strategy for Conquering the Blue Sky War" policy has lowered the AQI in North China and improved PM2.5 concentrations nationwide. Based on the above findings, the paper puts forward corresponding policy recommendations.

Distribution characteristics, source analysis and risk assessment of polycyclic aromatic hydrocarbons in sediments of Kuye River: a river in a typical energy and chemical industry zone.

This study systematically analyzed the distribution characteristics, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in Kuye River sediments, located in an energy and chemical industry base in northern Shaanxi, China. The results that revealed the concentrations of 16 PAHs in the sediment ranged from 1090.04 to 32,175.68 ng∙g-1 dw, with the four-ring PAHs accounting for the highest proportion. Positive matrix factorization analysis (PMF) revealed the main sources of PAHs as incomplete fossil fuel combustion, biomass combustion, and traffic emissions. The total toxic equivalent concentration of BaP, risk quotient, and lifetime carcinogenic risk of PAHs suggested moderate to high contamination of PAHs in the area. The higher incremental lifetime carcinogenic risk (ILCR) indicated that PAH ingestion was the primary route of impact on public health, with children potentially being more susceptible to PAH exposure. This study can provide valuable theoretical support for implementing pollution prevention measures and ecological restoration strategies for rivers in energy and chemical industry areas.

Spatial and Temporal Distribution Characteristics and Cytotoxicity of Atmospheric PM2.5 in the Main Urban Area of Lanzhou City.

PM2.5, as one of the most harmful pollutant in the atmospheric environment and population health, has received much attention. We monitored PM2.5 levels at five sampling sites in the Lanzhou City and collected PM2.5 particles from two representative sites for cytotoxicity experiment. The cytotoxicity of PM2.5 samples on A549 cells and migration ability of the cells were respectively detected by Cell Counting kit-8 (CCK-8) assay and scratch assay. We detected the levels of cellular inflammatory factors and oxidative damage-related biochemical indexes. RT-qPCR was used to detect the mRNA levels of NF-κB and epithelial-mesenchymal transition (EMT)-related genes. We found that the Lanlian Hotel station had the highest PM2.5 annual average concentration. The annual average concentration change curve of PM2.5 showed a roughly "U"-shaped distribution during the whole sampling period. The cytotoxicity experiment showed the viability of A549 cells decreased and the scratch healing rate increased in the 200 and 400 µg/mL PM2.5-treated groups. We also found 400 µg/mL PM2.5 induced changes in the mRNA levels of NF-κB and EMT-related genes, the mRNA levels of IKK-α, NIK, and NF-κB in the 400 µg/mL PM2.5 group were higher than those in the control group. The mRNA levels of E-cadherin decreased and α-SMA increased in the 400 µg/mL PM2.5 groups, and the mRNA levels of Fibronectin increased in the 400 µg/mL PM2.5 groups. Moreover, we found hydroxyl radical scavenging ability and T-AOC levels were lower, and LPO levels were higher in the 200 and 400 µg/mL PM2.5 groups, and the SOD activity of cells in the 400 µg/mL PM2.5 group decreased. And compared with the control group, the levels of TNF-α were higher in the 200 and 400 µg/mL PM2.5 groups and the levels of IL-1 were higher in the 400 µg/mL PM2.5 group. The results indicated that the cytotoxicity of atmospheric PM2.5 was related to oxidative damage, inflammatory response, NF-κB activity and EMT.

[Distribution and health risk assessment of pesticide pollution in raw water and drinking water within key river basins in China in 2022].

OBJECTIVE: To investigate the distribution and exposure levels of pesticides in raw water and drinking water in China, as well as to assess the potential health risks associated with long-term consumption. METHODS: A total of 83 typical water plants were selected in key river basins in China to collected samples of the raw water, finished water, and tap water. The online-solid phase extraction coupled with liquid chromatography-tandem mass spectrometry method was used to determine 13 pesticides, including acetochlor, atrazine, dimethoate, malathion, carbofuran, dichlorvos, chlorpyrifos, parathion, trifluralin, isoprothiolane, simetryn, methyl parathion, and metalaxyl, as well as 6 environmental metabolites, including carbendazim, malaoxon, 3-hydroxycarbofuran, deethyl atrazine, deisopropyl atrazine and hydroxy atrazine. The carcinogenic and non-carcinogenic risks of these pesticides were assessed. RESULTS: The concentrations of total amount of pesticides in the samples ranged from 0.1 ng/L to 1299.4 ng/L, with a median value of 64.7 ng/L. The detection rates of 5 pesticides or their metabolites exceeds 80%, namely acetochlor, atrazine, hydroxyl atrazine, deethyl atrazine, and metalaxyl. More than 6 pesticides or their metabolites were detected in 77.7% of the total 498 samples. The total concentration of pesticides during the wet season ranged from 1.1 ng/L to 1299.4 ng/L, with a median of 69.2 ng/L and a median average daily dose of 2.3 ng/(kg·d). The total concentration of pesticides in the dry season samples ranged from 0.1 ng/L to 543.5 ng/L, with a median of 60.2 ng/L and a median average daily dose of 2.0 ng/(kg·d). Among the 498 samples, the maximum carcinogenic risk of dichlorvos was 2.0×10~(-7), and the maximum carcinogenic risk of trifluralin was 1.1×10~(-10). The non-carcinogenic HI of 19 pesticides and metabolites pesticides was ≤6.0×10~(-3). Among them, the maximum HI of the middle route of the South to North Water Diversion Project, the lower reaches of the Yellow River, the eastern route of the South to North Water Diversion Project, the Liaohe River, and the Songhua River basin was 2.0×10~(-3)-6.0×10~(-3), while the HI of other basins was less than 1.0×10~(-3). CONCLUSION: Different concentrations of pesticides have been detected in raw water, finished water, and tap water of key river basins in China, with the highest total concentration of detected reaching 1299.4 ng/L. The carcinogenic risk was lower than 10~(-6) and the non-carcinogenic hazard index of 19 pesticides was less than 1, and both below the acceptable level. Because of the universality and diverse occurrence of these pesticides in drinking water, long-term exposure to pesticides is still a concern.

[Spatial distribution pattern of local tumor progression analysis after microwave ablation of hepatocellular carcinoma based on three-dimensional magnetic resonance imaging].

Objective: To investigate the spatial distribution pattern of local tumor progression (LTP) for hepatocellular carcinoma (HCC) ≤5 cm after microwave ablation. Methods: A retrospective analysis was performed on 169 HCCs with matched MRI before and after ablation from December 2009 to December 2019. A tumor MRI was reconstructed using three-dimensional visualization technology. LTP was classified as contact or non-contact, early or late stage, according to whether LTP was in contact with the edge of the ablation zone and the occurrence time (24 months). The tumor-surrounded area was divided into eight quadrants by using the eight-quadrant map method. An analysis was conducted on the spatial correlation between the quadrant where the ablative margin (AM) safety boundary was located and the quadrant where different types of LTP occurred. The t-test, or rank-sum test, was used for the measurement data. 2-test for count data was used to compare the difference between the two groups. Results: The AM quadrant had a distribution of 54.4% LTP, 64.2% early LTP stage, and 69.1% contact LTP, suggesting this quadrant was much more concentrated than the other quadrants (P < 0.001). Additionally, the AM quadrant had only 15.2% of non-contact type LTP and 17.1% of late LTP, which was not significantly different from the average distribution probability of 12.5% (100/8%) among the eight quadrants (P = 0.667, 0.743). 46.6% of early contact type LTP was located at the ablation needle tip, 25.2% at the body, and 28.1% at the caudal, while the location distribution probabilities of non-early contact LTP were 34.8%, 31.8%, and 33.3%, respectively. Conclusion: LTP mostly occurs in areas where the ablation safety boundary is the shortest. However, non-contact LTP and late LTP stages exhibit the feature of uniform distribution. Thus, this type of LPT may result from an inadequate non-ablation safety boundary.

Analysis of Lymph Node Metastasis and Risk Factors in 975 Patients with FIGO 2009 Stage IA-IIA Cervical Cancer.

OBJECTIVES: The objective of this study was to summarize the rate of lymph node metastasis (LNM) of patients with stage IA-IIA cervical cancer and further analyze its distribution characteristics and related risk factors. DESIGN: This study is a retrospective analysis of clinical data about cervical cancer. PARTICIPANTS: According to the International Federation of Gynecology and Obstetrics (FIGO) 2009 staging standard, 975 patients with stage IA-IIA cervical cancer treated in our hospital from January 2010 to December 2018. SETTING: This is a single-center study. METHODS: The incidence and distribution of LNM were analyzed, and the influencing factors of cervical cancer LNM were analyzed using univariate and multivariate logistic regression. RESULTS: In this study, the LNM rate was 14.8% (144/975), and a total of 20,288 lymph nodes were removed, among which 359 lymph nodes had metastasis. According to the number and frequency of metastatic lymph nodes in different regions, the metastatic rate was the highest in the external iliac regions. Univariate analysis showed that more than three pregnancies, tumor size >4 cm, gross type, FIGO stage, pathological type, positive lymphovascular space invasion (LVSI), deep cervical stromal invasion (outer half invasion), parametrial involvement, and uterine corpus invasion (UCI) were correlated with LNM (p < 0.05). Multivariate analysis showed that tumor lesion of >4 cm (odds ratio (OR) = 2.253, 95% confidence interval (CI): 1.486-3.416, p < 0.001), positive LVSI (OR = 5.353, 95% CI: 3.303-8.676, p < 0.001), deep cervical stromal invasion (OR = 3.461, 95% CI: 2.106-5.688, p < 0.001), and deep UCI (myometrial invasion ≥50%) (OR = 3.529, 95% CI: 1.321-9.427, p = 0.012) were independent risk factors for LNM. LIMITATIONS: Retrospective nature of the study and limitation to a single-center study are the limitations of the study. CONCLUSIONS: Patients with cervical cancer are more likely to have LNM with a tumor size of >4 cm, positive LVSI, deep cervical stromal invasion, or deep UCI. When these risk factors are present, the presence of LNM is possible, and attention should be paid. This study provides a certain reference value for predicting LNM risk for patients with early cervical cancer and for the stratified management of early cervical cancer treatment.

An experimental investigation of the erosion process and morphological characteristics of the tile-back type slope with non-uniform slopes based on a 3D reconstruction method.

Tile-back type slopes comprise ephemeral gullies (EGs) and hillslopes; they are a unique and widely distributed micro-landform in the Loess Plateau region of China. Gully erosion from these landforms is a serious issue, but the micro-landform makes the erosion process and its estimation complex. Quantifying soil erosion processes and their distribution characteristics at different positions on tile-back type slopes will provide a clearer picture for ecological restoration to control further soil degradation. This study investigated the erosion process of tile-back type slope with non-uniform slopes using a 3D photo-reconstruction method during eight successive simulated rainfall events. The results showed that EG erosion began with a chain of intermittent headcuts. When the accumulated rainfall reached 76 mm, serious collapses dramatically increased the amount of sediment by 216% after the first rainfall (cumulative rainfall was about 15 mm). We quantified the sediment contribution of EG erosion (46.20%), rill erosion (35.62%), and inter-rill erosion (18.18%) to total soil loss. The erosion area of the steep slope section and extremely steep slope section accounted for 33.26% and 66.74% of the total erosion area, respectively. Moreover, sediment amounts significantly correlated with morphological parameters, particularly the amount of EG erosion and maximum gully depth, with a correlation coefficient of 0.98. Cumulative gully length and erosion area had the greatest effect on rill erosion, with a correlation coefficient of 0.97. These results provide insight into the qualitative and quantitative understanding of EG erosion process on Loess Plateau of China and an important reference for the rational arrangement of EG control measures.

Organophosphate tri- and diesters in source water supply and drinking water treatment systems of a metropolitan city in China.

The water contaminations with organophosphate triesters (tri-OPEs) and diesters (di-OPEs) have recently provoked concern. However, the distributions of these compounds in natural water sources and artificial water treatment facilities are poorly characterized. A comprehensive study was therefore performed to measure their concentrations in a water source, a long-distance water pipeline, and a drinking water treatment plant (DWTP). Eight tri-OPEs and 3 di-OPEs were found to be widely distributed, with total concentrations in source water and pipelines ranging from 290.6 to 843.9 ng/L. The most abundant pollutants were tris(1-chloro-2-propyl) phosphate (TCPP), triethyl phosphate, tri-n-butyl phosphate (TnBP), and diphenyl phosphate (DPhP). Di-OPEs appeared to be removed less efficiently in the DWTP than the parent tri-OPEs, and the elimination efficiencies of tri-OPEs were structure-dependent. Long-distance pipeline transportation had no significant effect on the distributions of tri- and di-OPEs. Statistical analysis suggested that the sources of di-OPEs and the corresponding tri-OPEs differed, as did those of DPhP and di-n-butyl phosphate. A risk analysis indicated that tri-OPEs present limited ecological risks that are mainly due to TnBP and TCPP, and that the human health risks of tri-OPEs are negligible. However, di-OPEs (especially DPhP) may increase these risks. Further studies on the risks posed by di-OPEs in aquatic environments are therefore needed.

Combined assessment of health hazard and odour impact of soils at a contaminated site: a case study on a defunct pharmaceuticals factory in China.

Surveys and assessments of contaminated sites primarily focus on hazardous pollutants in the soil with less attention paid to odorants. This makes the management of contaminated sites difficult. In this study, hazardous and odorous pollutants in the soil were assessed for a large site that was previously used for production of pharmaceuticals to determine the degree and characteristics of soil contamination at pharmaceutical production sites, for undertaking rational remediation measures. The main hazardous pollutants at the study site were triethylamine, n-butyric acid, benzo(a)pyrene (BaP), N-nitrosodimethylamine (NDMA), dibenzo(a,h)anthracene (DBA), total petroleum hydrocarbons (C10-C40) (TPH), and 1,2-dichloroethane; TEA, BA, and isovaleric acid (IC) were the main odorants. As the type and distribution of hazardous and odorous pollutants differ, it is necessary to separately assess the impact of these pollutants at a contaminated site. Soils in the surface layer pose significant non-carcinogenic (HI = 68.30) and carcinogenic risks (RT = 3.56E-5), whereas those in the lower layer only pose non-carcinogenic risks (HI > 7.43). Odorants were found at considerable concentrations both in the surface and lower layers, with the maximum concentrations being 29,309.91 and 41.27, respectively. The findings of this study should improve our understanding of soil contamination at former pharmaceutical production sites and should inform the assessment of the risks posed by contaminated sites, with problems associated with odour, and possible remediation strategies.

Distribution characteristics and potential ecological risk assessment of heavy metals in soils around Shannan landfill site, Tibet.

At present, sanitary landfill is mainly used for domestic waste treatment in Shannan City, Tibet. However, there are few studies on heavy metals in the soil around the landfill in Shannan city. Therefore, the surrounding soil of Luqionggang landfill in Shannan City, Tibet Autonomous Region, is taken as the research object. In the study, the geo-accumulation index method, Nemerow comprehensive pollution index method and potential ecological risk index method are mainly used to evaluate the pollution and risk of heavy metals in the soil around the landfill site. The main results are as follows: The average pH value of the soil around the landfill site is 9.37, belonging to the strong alkaline range. The average values of heavy metals Hg and Ni in soil exceeded the background content, and the average contents of other heavy metals Cu, Pb, Zn, Cr, As and Cd did not exceed the background content. The average content of these eight heavy metals did not exceed the screening value of the national soil environmental quality standard. In the horizontal direction, the average content of heavy metal elements Cu, Cr, Cd, Hg and Ni is relatively high in the west. The average content of heavy metals As, Zn and Pb in the north, east and south is slightly higher than that in the west. And the farther away from the landfill, the less the soil is affected by heavy metals. The evaluation results of geo-accumulation index show that heavy metal Hg is the most affected. The average value of the comprehensive pollution index is 2.969, which is between 2 and 3, belonging to the moderate pollution level. And the west side of the landfill (downstream area) is greatly affected. The evaluation results of potential ecological hazard pollution index show that the potential risk index of single pollutants of heavy metals Cu, Pb, Zn, Cr, Ni, As and Cd belongs to low ecological hazard level, and the potential risk index of single pollutants of heavy metal Hg belongs to relatively heavy ecological hazard level. On the whole, the total potential risk coefficient belongs to medium pollution hazard degree. According to the correlation analysis, there is no significant correlation between heavy metal elements As and Hg and the other six heavy metal elements. In addition, the pollution source of heavy metal As may be mainly soil forming factors and the pollution source of Hg may be mainly human factors.

Spatial distribution and migration of lead and zinc and the influence of parent materials in typical paddy soils of Hunan Province, China.

This study aimed to investigate the distribution and migration characteristics of lead (Pb) and zinc (Zn) in paddy soils in Hunan Province, China. A total of 343 soil samples from 63 profiles were collected from typical regions. The concentration, spatial distribution, and migration behaviors of Pb and Zn in the paddy soils were examined. The results showed that (1) the concentration ranges of Pb and Zn in the surface layer were 17.62-114.07 mg/kg and 44.98-146.84 mg/kg, respectively. (2) The content was higher in the middle and lower reaches of the Xiangjiang River basin horizontally and exhibited shallow enrichment characteristics vertically. (3) Pb migration was weaker than Zn migration, and the parent material had the most significant influence on Pb and Zn content in the bottom soil layer. The research results will clarify the characteristics of Pb and Zn contents in paddy soils in Hunan Province, further understand the horizontal distribution and vertical migration and transformation characteristics of Pb and Zn contents in paddy soils, and provide basic data for scientific rice cultivation and safe food production.

Distribution and transformation of potentially toxic elements in crack under coal mining disturbance.

In China, coal provides about 56.8% of the energy. Most of China's coal mines are shaft mines, which cause the surface to collapse and crack during the mining process. The soil near the cracks changes its physicochemical properties due to the altered stress conditions. This will affect the distribution of PTEs in the soil. We collected 18 samples from a selected crack in the abandoned land. The pH, Eh, and PTE and their fractions of the samples were determined. With the test results, we understand the distribution characteristics of pH, Eh, PTEs, and their fractions at the cracks. Meanwhile, we explored the key factors that contribute to this distribution. It was determined that crack decreases surface soil pH while increasing Eh. The total amount of 7 PTEs is higher in the bottom soil of the main crack and 2 m away from the main crack. The content of reducible fractions of PTEs increases with the increase of soil Eh. The oxidizable and residual fractions of PTEs adsorbed to the clay particles migrate to and enrich the deeper layers of the main crack. This study emphasizes the effect of crack generation on the distribution of PTEs in soil. It provides insights to describe the distribution of PTE throughout the full life cycle of crack.

Distribution characteristics of photoinitiators and their flux estimation from the Pearl River Delta to the coastal waters of the South China Sea.

Photoinitiators (PIs) are widely used in industrial polymerization processes. It has been reported that PIs are ubiquitous in indoor environments and that humans are exposed to PIs, but the occurrence of PIs in natural environments are rarely known. In the present study, 25 PIs, including 9 benzophenones (BZPs), 8 amine co-initiators (ACIs), 4 thioxanthones (TXs) and 4 phosphine oxides (POs), were analyzed in water and sediment samples collected from eight riverine outlets of the Pearl River Delta (PRD). Eighteen, 14, and 14 of the 25 target PIs were detected in water, suspended particulate matter (SPM) and sediment samples, respectively. The total concentrations of PIs in water, SPM, and sediment were in the ranges of 2.88‒96.1 ng/L, 9.25‒923 ng/g dry weight (dw), and 3.79‒56.9 ng/g dw, with geometric mean concentration (GM) of 10.8 ng/L, 48.6 ng/g dw, and 17.1 ng/g dw, respectively. A significant linear regression was observed between the log partitioning coefficients (Kd) values of PIs and their log octanol water partition coefficient (Kow) values (R2 = 0.535, p < 0.05). The annual riverine input of PIs to the coastal waters of the South China Sea via eight main outlets of the PRD was estimated to be 4.12 × 103 kg/year, and the ∑BZPs, ∑ACIs, ∑TXs and ∑POs contributed to 1.96 × 103, 1.24 × 103, 89.6 and 830 kg/year, respectively. This is the first report of a systematic description of the occurrence characteristics of PIs exposure in water, SPM, and sediment. The environmental fate and risks of PIs in aquatic environments need further investigations.

[Epidemiological characteristics and survival analysis of reported pneumoconiosis in Chengdu, 2012-2021].

Objective: To explore theepidemiological characteristics and analyse the survival of pneumoconiosis in Chengdu from 2011 to 2021, providing scientific evidence for further prevention and control. Methods: In April 2022, the pneumoconiosis report card of Chengdu from 2012 to 2021 and survival data were collected from the China Disease Control and prevention information system and the occupational pneumoconiosis follow-up survey project.The data of the report card was reorganized and analyzed by R4.4.0 software. Chi-square test was used to compare the case composition ratio between groups. The annual trend of the number of new pneumo coniosis cases was analyzed by linear regression model Kaplan-Meier method was used for survival analysis and log-rank test was used for comparison of survival curves between groups. Results: 816 cases of pneumoconiosis were reported in Chengdu from 2011 to 2021, including 522 cases of stage Ⅰ (63.97%, 522/816), 148 cases of stage Ⅱ (18.14%, 148/816) and 146 cases of stage Ⅲ pneumoconiosis (17.89146/816) ; There were 596 cases of silicosis (73.04%, 596/816), 143 cases of coal worker's pneumoconiosis (17.52%, 143/816). New onset pneumoconiosis was mainly male (810 cases, 99.26%). The median age of diagnosis and the 25th and 75th percentile were 63 (51-71) years old, the median length of dust exposure were 12.00 (5.92-28.00) years, and the types of work were mainly rock drillers (24.63%, 201/816), tunneling workers (19.36%, 158/816) and coal miners (13.60%, 111/816). Among 816 cases of new pneumoconiosis, 35 cases were lost to follow-up (4.29%, 35/816), 605 cases survived and 176 cases died. The 5-year survival rate was 78.6% and the 10-year survival rate was 65.8%. Conclusion: The number of pneumoconiosis reported in Chengdu was relatively stable in recent years. The main type of pneumoconiosis was silicosis, which was concentrated in regions, industries and types of work. We should continue to strengthen the prevention and treatment of pneumoconiosis.

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OBJECTIVES: To investigate the distribution characteristics of non-bacterial pathogens in community-acquired pneumonia (CAP) in children. METHODS: A total of 1 788 CAP children admitted to Shenyang Children's Hospital from December 2021 to November 2022 were selected. Multiple RT-PCR and capillary electrophoresis were used to detect 10 viral pathogens and 2 atypical pathogens, and serum antibodies of Chlamydial pneumoniae (Ch) and Mycoplasma pneumoniae (MP) were detected. The distribution characteristics of different pathogens were analyzed. RESULTS: Among the 1 788 CAP children, 1 295 children were pathogen-positive, with a positive rate of 72.43% (1 295/1 788), including a viral pathogen positive rate of 59.68% (1 067/1 788) and an atypical pathogen positive rate of 22.04% (394/1 788). The positive rates from high to low were MP, respiratory syncytial virus (RSV), influenza B virus (IVB), human metapneumovirus (HMPV), human rhinovirus (HRV), human parainfluenza virus (HPIV), influenza A virus (IVA), bocavirus (BoV), human adenovirus (HADV), Ch, and human coronavirus (HCOV). RSV and MP were the main pathogens in spring; MP had the highest positive rate in summer, followed by IVA; HMPV had the highest positive rate in autumn; IVB and RSV were the main pathogens in winter. The positive rate of MP in girls was higher than that in boys (P<0.05), and there were no significant differences in other pathogens between genders (P>0.05). The positivity rates of certain pathogens differed among age groups (P<0.05): the positivity rate of MP was highest in the >6 year-old group; the positivity rates of RSV and Ch were highest in the <1 year-old group; the positivity rates of HPIV and IVB were highest in the 1 to <3 year-old group. RSV, MP, HRV, and HMPV were the main pathogens in children with severe pneumonia, while MP was the primary pathogen in children with lobar pneumonia, and MP, IVB, HMPV, RSV, and HRV were the top 5 pathogens in acute bronchopneumonia. CONCLUSIONS: MP, RSV, IVB, HMPV, and HRV are the main pathogens of CAP in children, and there are certain differences in the positive rates of respiratory pathogens among children of different ages, genders, and seasons.