Search

The deterioration of water resources has been recognized as an urgent environmental problem due to population growth, industrialization, urbanization and agricultural activities, where water quality assessment is the basis for forward-looking decisions on water quality management. In this study, the Nemerow index method, traditional fuzzy mathematics and improved fuzzy mathematics methods were applied to assess the water quality of the Liao River based on twenty-three water quality parameters. The results revealed that most monitoring stations in the study area were moderately polluted. The improved fuzzy mathematics method gives more appropriate than the other two methods in water quality assessment. The self-organizing map (SOM) results suggested that chemical oxygen demand (COD Cr) significantly affects water quality. The human health risk model was applied to calculate hazard indices (HI) to assess human health risks, indicating that the health risk of the Liao River caused by heavy metals was within an acceptable limit and did not pose a significant human health risk in the study area. Meanwhile, the health risk caused by heavy metals to children was higher than in adults. The results of the present study could provide new insights into water quality assessment, risk warning and public health protection in typical urbanized watersheds. [ABSTRACT FROM AUTHOR]

Exploring the responses of greenhouse gas (GHG) emissions to land use conversion or reversion is significant for taking effective land use measures to alleviate global warming. A global meta‐analysis was conducted to analyze the responses of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions to land use conversion or reversion, and determine their temporal evolution, driving factors, and potential mechanisms. Our results showed that CH4 and N2O responded positively to land use conversion while CO2 responded negatively to the changes from natural herb and secondary forest to plantation. By comparison, CH4 responded negatively to land use reversion and N2O also showed negative response to the reversion from agricultural land to forest. The conversion of land use weakened the function of natural forest and grassland as CH4 sink and the artificial nitrogen (N) addition for plantation increased N source for N2O release from soil, while the reversion of land use could alleviate them to some degree. Besides, soil carbon would impact CO2 emission for a long time after land use conversion, and secondary forest reached the CH4 uptake level similar to that of primary forest after over 40 years. N2O responses had negative relationships with time interval under the conversions from forest to plantation, secondary forest, and pasture. In addition, meta‐regression indicated that CH4 had correlations with several environmental variables, and carbon–nitrogen ratio had contrary relationships with N2O emission responses to land use conversion and reversion. And the importance of driving factors displayed that CO2, CH4, and N2O response to land use conversion and reversion was easily affected by NH4+ and soil moisture, mean annual temperature and NO3−, total nitrogen and mean annual temperature, respectively. This study would provide enlightenments for scientific land management and reduction of GHG emissions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Circular RNA circ_0124644 has crucial regulation in the progression of coronary artery diseases, including atherosclerosis (AS). The aim of this study was to explore the regulatory mechanism of circ_0124644 in oxidized low-density lipoprotein (ox-LDL)-induced endothelial injury in human umbilical vein endothelial cells (HUVECs). METHODS: Cell viability and proliferation were assessed using cell counting kit-8 (CCK-8) assay and EdU assay. The apoptosis detection was performed by flow cytometry. Angiogenesis was evaluated through tube formation assay. The protein analysis was conducted via western blot. Inflammatory cytokines were examined by enzyme-linked immunosorbent assay (ELISA). The expression determination of circ_0124644, microRNA-370-3p (miR-370-3p) and forkhead box protein O4 (FOXO4) was performed through reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to analyze the interaction between targets. RESULTS: Treatment of ox-LDL resulted in the inhibition of cell viability, proliferation and angiogenesis but the promotion of apoptosis and inflammation in HUVECs. These ox-LDL-induced cell damages were alleviated after the downregulation of circ_0124644. Circ_0124644 interacted with miR-370-3p, and the regulatory role of circ_0124644 was associated with the sponge function of miR-370-3p. Additionally, miR-370-3p targeted FOXO4 and circ_0124644 increased the expression of FOXO4 through acting as a sponge of miR-370-3p. Overexpression of miR-370-3p protected from ox-LDL-induced injury via the downregulation of FOXO4. CONCLUSION: All results revealed that circ_0124644 accelerated endothelial injury in ox-LDL-treated HUVECs by mediating miR-370-3p-related FOXO4 expression. [ABSTRACT FROM AUTHOR]

Geochemical properties of rare earth elements (REEs) have the potential to represent the provenance and depositional history of surface sediment in aquatic environments. In this study, both surface and core sediment samples were collected from Dongting Lake to investigate the distribution characteristics and source of REEs by combining the methodologies of geostatistics, positive matrix factorization (PMF) model, discriminant function (DF), and provenance index (PI) based on REEs geochemical parameters. The results indicated that the total REEs content in sediment samples ranged from 129.12 to 284.02 μg g−1, with the average REEs content calculated to be 197.95 μg g−1. Light REEs (LREEs) comprised >90% of the total REEs, indicating that there was an enrichment of LREEs in the sediment samples. The REEs of the surface sediment showed strong spatial variation, with relatively high values located in Eastern Dongting Lake and relatively lower levels in Western Dongting Lake. Moreover, the vertical distributions of ∑REEs, ∑LREEs and ∑HREEs at most sampling sites behaved similarly with rapid increase until about 6–8 cm, followed by a downward trend with some irregularities. The strong association between most REEs confirmed that they often have a positive correlation and co-existence in sediment. The PMF model revealed that most of the REEs in the surface sediment were derived from natural sources with some anthropogenic inputs also serving as contributing sources. The DF and PI results indicated that the REEs distribution pattern in the surface sediment of Dongting Lake was similar to that of the Yangtze River, suggesting that Yangtze River had been more of an influence on sediment loads than the upstream tributaries. This study highlights the broader applicability of the REEs tracing method in sediment transport processes and can provide new knowledge regarding source apportionment analysis of sediment-related contaminants in aquatic environments. Unlabelled Image • Geochemical characteristics of REEs in sediment from Dongting Lake were studied. • Strong correlations were presented between most REEs in sediments. • Natural and anthropogenic sources of REEs were identified by PMF modeling. • DF and PI were used to discriminate the source areas of surface sediments. [ABSTRACT FROM AUTHOR]

Abstract Due to increasing anthropogenic disturbance, various pollutants have been frequently detected in QingHai-Tibet Plateau, where the environment is extremely fragile and sensitive to human activities. In this study, 51 sampling sites with different land covers were selected in a sub-basin in the Huangshui watershed in eastern QingHai-Tibet Plateau. A total of 102 soil samples were collected at surface (0–20 cm) and subsurface (20–40 cm) depths for studying on heavy metal pollution in this region. The relationships between land cover types and spatial distribution of five heavy metals Cr, Cu, Cd, Pb, and Zn were systematically analyzed combing field survey, remote-sensing database, and geostatistical methods. The relationships between soil physiochemical properties and heavy metals were assessed by geostatistics, co-occurrence network analysis and geographically weighted regression (GWR) model. The results indicated that the average concentrations of all five heavy metals in soil were higher than the local background values, indicating the influence of anthropogenic inputs of these elements into environment. Strong positive correlations were observed between some heavy metals and soil physic-chemical properties in different land covers, combined with the geoaccumulation index, human activities contribution can be interpolated. The Cr and Zn in surface soils are explainers for Cr and Zn in subsurface soils in the GWR models respectively, as well as the area of different land cover. Cd contamination was specifically analyzed due to its degree of contamination and then the sources of Cd were identified such as energy production as well as chemical fertilizers. The results of this study can provide basic data for long-term accumulation of heavy metals in soils under different land uses in QingHai-Tibet Plateau. Graphical abstract Unlabelled Image Highlights • Correlation between heavy metals and land use was analyzed by polygon definition and raster correlation. • Geographically weighted regression was used to identify the relationships between heavy metals. • Contamination sources were identified using combination of land cover and geoaccumulation index. [ABSTRACT FROM AUTHOR]

Abstract Geochemical distribution of trace elements in sediments could reflect the impact of anthropogenic activities on environmental changes in aquatic ecosystems. In this study, rare earth elements (REEs) were used as geochemical tracers to study the environmental processes in a complex and dynamic aquatic environment. Both surface and core sediment samples were collected from Poyang Lake, the largest freshwater lake located in the middle-low region of the Yangtze River. Sediment samples were analyzed for their respective REE spatial distributions, fractionation, and co-occurrence patterns. The inner relationships and geochemistry characters of REEs were assessed by geostatistics and co-occurrence network analysis. Results indicated that total REE concentrations in the sediments from Poyang Lake ranged from 145.1 to 351.1 μg g−1, with an average concentration of 254.0 μg g−1. Light rare earth element (LREE, La - Sm) enrichment was evident in all sediment samples, indicating the effects of river-lake interactions and the contributions from terrestrial inputs. The negative Ce and Eu anomalies were found in most sediment samples, indicating the differentiation between Ce, Eu, and other REEs in the processes of sediment transportation and deposition. Collectively, the identification of the major contamination sources of REEs in sediment, analyzed by the patterns of the co-occurrence networks and REE fractionation, revealed that the REEs in sediments from Poyang Lake originated both natural and anthropogenic sources and were disturbed by the impact of anthropogenic activities. Graphical abstract Image Highlights • Accumulation and distribution of REEs in sediments from Poyang Lake were studied. • Obvious fractionation between LREEs and HREEs is observed in sediments. • A weak Ce and Eu anomalies were found in most of the sediments. • Co-occurrence and fractionation patterns of REEs were used for source identification. [ABSTRACT FROM AUTHOR]

Abstract Water resources and water quality are restrictive factors in the Chinese Loess Plateau (CLP), a unique area with most severe soil erosion, fragile ecology and water shortage. River and well water samples were firstly analyzed, and multiple methods and indexes, including principal component analysis (PCA), correlation analysis (CA), sodium adsorption ratio (SAR), water quality index (WQI), hazard quotient (HQ), and hazard index (HI), were used to investigate characteristics, water quality and health risk assessment of trace elements in CLP. The average trace elements concentrations were higher than the world average with a slightly alkaline characteristic. PCA and CA showed that Al, Fe, Li, B, As, and F had natural origins from loess weathering and leaching; Cr, Pb, Cd, Cu, Ag, and Tl were mainly from anthropogenic input; Co, Ni, and Mn were dominated by both anthropogenic and natural sources. The poor river water quality was mainly related with high sodium (alkalinity) and salinity hazard. The poor well water quality samples with high WQI values, especially for As, Cr, and B, were distributed in the northwest and the Fenhe River sub-basin. The pollution level of trace elements in rivers in CLP was in medium level compared with other rivers worldwide. Arsenic pollution was the worst in well water and was the potential pollutant in river water especially for children. Arid climate together with anthropogenic input and special water characteristics (high Na, pH, and low Ca) aggravated As pollution. More work should be done to monitor the secular variation and remove As in the high As areas. The results of this study can provide the basic data for efficient water management and human health protection in CLP. Graphical abstract Unlabelled Image Highlights • The pollution level of trace elements in Loess Plateau is in medium level. • As, Cr and B were the main pollutants of the natural waters. • Arsenic was the most important pollutant for non-carcinogenic risks. • Poor quality waters are distributed in the northwest and Fenhe River basin. • Arid climate and anthropogenic input are the main reasons for water pollution. [ABSTRACT FROM AUTHOR]

Sediment acts as both important sink and source for contaminants in aquatic systems. In the present study, the multivariable cokriging method and multiple statistical techniques, including group analysis (GA), factor analysis of mixed data (FAMD), correlation matrices (CMs), and enrichment factor (EF) were used to identify spatial distribution and sources of potentially toxic elements (PTEs) Cr, Cu, Cd, Pb, and Zn in surficial sediments of Dongting Lake in China. The results showed significant spatial heterogeneity in these PTEs in Dongting Lake. The average concentrations of Cr, Cu, Cd, Pb, and Zn were 131.5 ± 45.4, 49.7 ± 17.4, 2.2 ± 1.8, 59.2 ± 18.6, and 152.9 ± 48.0 mg/kg, respectively. The potential ecological risks posed by the trace elements (Cr, Cu, Cd, Pb, and Zn) were evaluated based on the multivariable cokriging predictions, and the results indicated that the ecological risks were high in Southern and Western Dongting Lakes. Multiple analyses showed that Cr, Cu and Zn primarily originated from industrial and domestic sewage wastewater, while Cd and Pb were primarily from agricultural and industrial sources. [ABSTRACT FROM AUTHOR]

Airborne fluoride associated with total suspended particles (TSP) and respirable particulate (PM 10 ) in the rare earth mining and smelting areas were analyzed during August 2012 and March 2013. In March, average concentrations of fluoride bound to TSP in the mining and smelting areas were 0.598 ± 0.626 μg/m 3 and 3.615 ± 4.267 μg/m 3 , respectively, whereas that in August were 0.699 ± 0.801 μg/m 3 and 1.917 ± 2.233 μg/m 3 , respectively. TSP samples were classified into four categories by different sampling periods and locations using Kohonen's self-organizing map, which demonstrates that high airborne fluoride concentrations in March in the smelting area were probably attributed to industrial emissions from smelting activities and wind-blown dust from tailings pond, influenced by meteorologic parameters such as temperature, relative humidity, precipitation and wind speed. The mean daily amount of fluoride inhaled in the mining and smelting areas were estimated to be in the range of 2.77–57.61 μg/day and 3.39–64.32 μg/day, respectively. These results indicate the high potential exposure level of fluoride inhaled for local residents in the polymetallic mining and smelting areas. [ABSTRACT FROM AUTHOR]

Exposure to radionuclide thorium (Th) has generated widespread public concerns, mainly because of its radiological effects on human health. Activity levels of airborne 232 Th in total suspended particulate (TSP) were measured in the vicinity of the largest rare earth mine in China in August 2012 and March 2013. The mean activity concentrations of 232 Th in TSP ranged from 820 μBq m − 3 in a mining area in August 2012 to 39,720 μBq m − 3 in a smelting area in March 2013, much higher than the world reference of 0.5 μBq m − 3 . Multistatistical analysis and Kohonen's self-organizing maps suggested that 232 Th in TSP was mainly derived from rare earth mining and smelting practices. In addition, personal inhalation exposures to 232 Th associated with respirable particulate (PM 10 ) were also measured among local dwellers via personal monitoring. The mean dose values for different age groups in the smelting and mining areas ranged from 97.86 to 417 μSv year − 1 and from 101.03 to 430.83 μSv year − 1 , respectively. These results indicate that people living in the study areas are exposed to high levels of widespread 232 Th. [ABSTRACT FROM AUTHOR]

High-technology rare earth elements (REEs) as emerging contaminants have potentially hazardous risks for human health and the environment. Investigating the sorption of REEs on soils is crucial for understanding their migration and transformation. This study evaluated the sorption mechanisms and influencing factors of the rare earth element yttrium (Y) on paddy soil via integrated batch sorption experiments and theoretical modeling analysis. Site energy distribution theory (SEDT) combined with kinetics, thermodynamics, and isotherm sorption models were applied to illustrate the sorption mechanism. In addition, the effects of phosphorus (P), solution pH, particle size of soil microaggregates, and initial Y content on the sorption processes were evaluated by self-organizing map (SOM) and Boruta algorithm. The sorption kinetic behavior of Y on paddy soil was more consistent with the pseudo-second-order model. Thermodynamic results showed that the Y sorption was a spontaneous endothermic reaction. The generalized Langmuir model well described the isotherm data of Y sorption on heterogeneous paddy soil and soil microaggregates surface. The maximum sorption capacity of Y decreased with increasing soil particle size, which may be related to the number of sorption sites for Y on paddy soil and soil microaggregates, as confirmed by SEDT. The heterogeneity of sorption site energy for Y was the highest in the original paddy soil compared with the separated soil microaggregates. The SOM technique and Boruta algorithm highlighted that the initial concentration of Y and coexisting phosphorus played essential roles in the sorption process of Y, indicating that the addition of phosphate fertilizer may be an effective way to reduce the Y bioavailability in paddy soil in practice. These results can provide a scientific basis for the sustainable management of soil REEs and a theoretical foundation for the remediation of REEs-contaminated soils. [Display omitted] • Yttrium sorption is an endothermic process mainly involving specific chemisorption. • The number of yttrium sorption sites decreases with increasing soil particle size. • Heterogeneity of sorption site energy is reduced in separated microaggregates. • The initial content of yttrium is the main limiting factor for yttrium sorption. • Coexisting phosphorus is more important for yttrium sorption than pH. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is a key indicator of the aquatic organism growth and eutrophication in lakes. The distribution and speciation of P and its release characteristics from sediments were investigated by analyzing sediment and water samples collected during high flow and low flow periods. Results showed that the average concentrations (ranges) of total phosphorus (TP) in the surface and deep water were 0.06 mg L-1 (0.03–0.13 mg L-1) and 0.15 mg L-1 (0.06–0.33 mg L-1), respectively, while the average concentration (range) of TP in sediments was 709.17 mg kg-1 (544.76–932.11 mg kg-1). The concentrations of TP and different forms of P varied spatially in the surface sediments, displaying a decreasing trend from south to north. P also varied topographically from estuarine areas to lake areas. The vertical distribution of TP and different forms of P were observed to decrease as depth increased. The P concentrations during the low flow period were higher than those during the high flow period. Inorganic phosphorus (IP) was the dominant form of P, accounting for 61%–82% of TP. The concentration of bioavailable phosphorus in sediments was relatively large, indicating a high risk of release to overlying water. The simulation experiment of P release from sediments showed that the release was relatively fast in the first 0-5 min and then decreased to a plateau after 1 hr. Approximately 84–89% of the maximum amount of P was released during the first hour. [ABSTRACT FROM AUTHOR]

Soil physicochemical properties can not only reflect ecosystem integrity, land quality and biogeochemical processes, but also are impacted by diverse land use types formed by intensive human activities. Exploring the comprehensive function of land use types and environmental factors on soil properties are of great significance for the relative land management, nutrition cycling and agricultural sustainable development. And little previous studies considered the inherent relations between soil properties under the dual effects of the above two, especially in an area with high land use intensity. This study tried to achieve the comprehensive research of human activities and environmental factors on soil properties through the study of the functions on soil properties from the environment factors under different land use types in the Beijing-Tianjin-Hebei region, which is a typical area with the most intense human activities in China. In this study, soil samples were collected in an area typified by intensive human activities in the Baiyangdian Watershed in the Beijing-Tianjin-Hebei region. The relationships between soil properties and environmental factors as well as the relationships between soil properties and land use intensity were explored by principal component analysis and geographically weighted regression (GWR) respectively. Additionally, impacts on soil properties from environmental factors were explored by structural equation modeling (SEM). GWR results suggested that pH was positively related to land use intensity (LUI); comparatively, all other soil properties were negatively related to LUI. SEM results showed that precipitation, temperature, and elevation all had direct and indirect influences on soil properties. Moreover, soil organic carbon was not only directly affected by environmental factors, but also indirectly through total phosphorus content in residential areas and plain farmland, pH in mountainous farmland areas, and bulk density in residential areas and mountainous farmland. Our work focus on the combined function of environmental factors and land uses on soil properties under various land use types with different human activities intensities. Our main conclusion from the above findings was that precipitation and temperature are both important factors that impact soil properties. High temperature and improper agricultural activities also reduced soil carbon accumulation. These findings underscore that scientific fertilizer addition during farming and soil quality management such as planning a proper reclamation range should be advocated in areas with intensive human activities. Taken together, our research will allow for a better understanding of the variations in soil properties and other influential factors in the context of human activities. [Display omitted] • Comprehensive effects of land use and environmental factors were analyzed. • Direct, indirect, and total influences on soil properties were explored. • The interaction of land use and environment was important to soil properties. • Precipitation and temperature had significant impacts on soil organic carbon. [ABSTRACT FROM AUTHOR]

Highlights: [•] Rare earth elements has influence on P adsorption process in soil. [•] P adsorption declined when soils were amended with lower concentration rare earth. [•] Langmuir equation fitted P adsorption in all five types soils. [•] P desorption increased when soil were amended with rare earth. [ABSTRACT FROM AUTHOR]

Abstract: Rare earth elements (REEs) have been increasingly emitted into the atmosphere with a worldwide increase in use of these metals. However, the research on REEs in atmospheric particulates is fairly limited. In this paper, atmospheric particulates including total suspended particulate (TSP) matter and particles with an equivalent aerodynamic diameter less than 10 μm (PM10) were collected around a rare earth mine tailing in Baotou, the largest rare earth industrial base in China, in August 2012 and March 2013, for the analyses of REE levels and distributions. The total concentrations of REEs for TSP were 172.91 and 297.49 ng/m3, and those for PM10 were 63.23 and 105.52 ng/m3, in August 2012 and March 2013, respectively. Enrichment factors for all 14 analyzed REEs in the TSP and PM10 indicated that the REE enrichment in atmosphere particulates was caused by anthropogenic sources and influenced by the strong wind in spring season. The spatial distribution of REEs in TSP showed a strong gradient in the prevailing wind direction. The chondrite-normalized patterns of REEs in TSP and PM10 were similar with the conspicuous fractionation between light REEs and heavy REEs. [Copyright &y& Elsevier]

Abstract: The Bayan Obo mine, located in Inner Mongolia, China, is the largest light rare earth body ever found in the world. The research for rare earth elements (REEs) enrichment in atmospheric particulates caused by mining and ore processing is fairly limited so far. In this paper, atmospheric particulates including total suspended particulate (TSP) matter and particles with an equivalent aerodynamic diameter less than 10μm (PM10) were collected around the Bayan Obo mine region, in August 2012 and March 2013, to analyze the levels and distributions of REEs in particles. The total concentrations of REEs for TSP were 149.8 and 239.6ng/m3, and those for PM10 were 42.8 and 68.9ng/m3, in August 2012 and March 2013, respectively. Enrichment factor was calculated for all 14 REEs in the TSP and PM10 and the results indicated that REEs enrichment in atmosphere particulates was caused by anthropogenic sources and influenced by the strong wind in springtime. The spatial distribution of REEs in TSP showed a strong gradient concentration in the prevailing wind direction. REE chondrite normalized patterns of TSP and PM10 were similar and the normalized curves inclined to the right side, showing the conspicuous fractionation between the light REEs and heavy REE, which supported by the chondrite normalized concentration ratios calculated for selected elements (La N /Yb N , La N /Sm N , Gd N /Yb N ). [Copyright &y& Elsevier]

Ionic antibiotics and metals generally coexist, and their interaction can affect their sorption behaviors onto soil minerals, therefore determining their environmental hazards. This study investigated the sorption and cosorption of Zn(II) and chlortetracycline (CTC) onto montmorillonite at different solution pH (3−10) using batch experiments and extended X-ray absorption fine structure (EXAFS) analysis. The Langmuir model could reproduce well the sorption isotherms of Zn(II) and CTC. The presence of CTC/Zn(II) could promote the maximum sorption capacity (Q m) of Zn(II)/CTC, based on site energy distribution (SED) theory. Generally, Zn(II) sorption increased with pH increasing. Comparatively, CTC sorption decreased as pH increased till approximately pH 5.0, then increased continuously with pH increasing. Both CTC and Zn(II) co-existence enhanced their individual sorption in both acidic and neutral environments. The processes behind CTC and Zn(II) sorption mainly included cation exchange and surface complexation. The EXAFS data evidenced that the presence of CTC could alter the species of Zn(II) on montmorillonite via surface complexation at pH 4.5 and 7.5, with Zn-CTC complexes being the predominant species on montmorillonite at pH 7.5. At pH 9.5, Zn(II) may exist onto montmorillonite in precipitated form similar to Zn-Al hydrotalcite-like compound (HTlc) regardless of CTC presence. [Display omitted] • Coexistence of pollutants increased their individual sorption on montmorillonite. • The increase of sorption sites was confirmed by site energy distribution theory. • Chlortetracycline mainly complexed with zinc in solutions at pH 7.0–9.0. • The species of zinc on montmorillonite were characterized by EXAFS. [ABSTRACT FROM AUTHOR]

Ionic antibiotics and metals generally coexist, and their interaction can affect their sorption behaviors onto soil minerals, therefore determining their environmental hazards. This study investigated the sorption and cosorption of Zn(II) and chlortetracycline (CTC) onto montmorillonite at different solution pH (3−10) using batch experiments and extended X-ray absorption fine structure (EXAFS) analysis. The Langmuir model could reproduce well the sorption isotherms of Zn(II) and CTC. The presence of CTC/Zn(II) could promote the maximum sorption capacity (Q m) of Zn(II)/CTC, based on site energy distribution (SED) theory. Generally, Zn(II) sorption increased with pH increasing. Comparatively, CTC sorption decreased as pH increased till approximately pH 5.0, then increased continuously with pH increasing. Both CTC and Zn(II) co-existence enhanced their individual sorption in both acidic and neutral environments. The processes behind CTC and Zn(II) sorption mainly included cation exchange and surface complexation. The EXAFS data evidenced that the presence of CTC could alter the species of Zn(II) on montmorillonite via surface complexation at pH 4.5 and 7.5, with Zn-CTC complexes being the predominant species on montmorillonite at pH 7.5. At pH 9.5, Zn(II) may exist onto montmorillonite in precipitated form similar to Zn-Al hydrotalcite-like compound (HTlc) regardless of CTC presence. [Display omitted] • Coexistence of pollutants increased their individual sorption on montmorillonite. • The increase of sorption sites was confirmed by site energy distribution theory. • Chlortetracycline mainly complexed with zinc in solutions at pH 7.0–9.0. • The species of zinc on montmorillonite were characterized by EXAFS. [ABSTRACT FROM AUTHOR]

Abstract: Controlling phosphorous (P) inputs through management of its sources and transport is critical for limiting freshwater eutrophication. In this study, characteristics of exogenous rare earth elements (REEs) and P and their losses with surface runoff (both in the water and sediments) during simulated rainfall experiments (83mmh−1) were investigated. The results revealed that on average most REEs (La, 94%; Nd, 93%; Sm, 96%) and P (96%) transported with sediments in the runoff. The total amounts of losses of REEs and P in the runoff were significantly correlated, suggesting the possibility of using REEs to trace the fate of agricultural nonpoint P losses. [Copyright &y& Elsevier]

Precision agriculture relies on the rapid acquisition and analysis of agricultural information. An emerging method of agricultural monitoring is unmanned aerial vehicle low-altitude remote sensing (UAV-LARS), which possesses significant advantages of simple construction, strong mobility, and high spatial-temporal resolution with synchronously obtained image and spatial information. UAV-LARS could provide a high degree of overlap between X and Y during key crop growth periods that is currently lacking in satellite and remote sensing data. Simultaneously, UAV-LARS overcomes the limitations such as small scope of ground platform monitoring. Overall, UAV-LARS has demonstrated great potential as a tool for monitoring agriculture at fine- and regional-scales. Here, we systematically summarize the history and current application of UAV-LARS in Chinese agriculture. Specifically, we outline the technical characteristics and sensor payload of the available types of unmanned aerial vehicles and discuss their advantages and limitations. Finally, we provide suggestions for overcoming current limitations of UAV-LARS and directions for future work. [ABSTRACT FROM AUTHOR]

In the twenty-first century, with the development of urbanization, large-scale mine wastelands in peri-urban areas have become increasingly closely related to the daily lives of urban and rural residents. Adopting a reuse method that meets the health needs of these residents, restoration, construction of mine wastelands in the suburbs of cities, and the formation of high-quality healthy environments and service supply are in line with the demands of healthy city construction and sustainable development. In addition, they have received increasing attention from all sectors of society. Based on the main criteria for constructing a healthy urban environment, this paper takes the comprehensive remediation and construction project of mine wastelands in the Taiyuan Xishan Ecological and Cultural Tourism Demonstration Area as a case study. It uses on-site surveys and an open-ended web-based questionnaire. It focuses on researching the perceived health needs of urban and rural residents in Taiyuan City, Shanxi Province, China concerning the main elements that determine health, such as the natural ecological environment, the construction of facilities and activities, and the local economic and industrial development. The results of 748 questionnaires that were completed by participants who effectively participated in the survey show that most participants preferred a comprehensive development model (86.6%) to reuse these areas. In addition, the specific needs of urban and rural residents for health safety, equity and quality, and healthy low-carbon industries should be considered. The differences in demand among groups of citizens due to different ages, living distances, levels of education, and occupations should be comprehensively considered. This paper demonstrates that a full understanding of the health needs of residents has great practical significance when improving the healthy environment and service supply level in mine wasteland restoration and construction and promoting the development of regional healthy city construction. Recently, the healthy environment and sustainable development of areas that host large-scale mine wastelands on the outskirts of cities have received increasing attention from all sectors of society. This paper suggests that during the reuse and construction of these areas, government management, development, and construction companies, planning and design organizations, and other departments that are involved in policy formulation and construction implementation should give full consideration to the perceived health needs of urban and rural residents in the host city, and to groups of residents of different ages, living distances, occupations, and educational levels, to form a high-quality and equitable health environment and services in the area. In addition, active public participation, on-site research, and interviews are essential for relevant departments to improve their understanding of resident health needs. [ABSTRACT FROM AUTHOR]

The Qarhan Salt Lake is the largest brine lake on the Qinghai-Tibet Plateau (QTP), which contains some potentially toxic elements (PTEs) due to the increase of human activities. This study endeavor encompassed the collection of 62 sediment samples from eight rivers that recharge the Qarhan Salt Lake, and the measurement of seven PTEs' concentrations (As, Hg, Pb, Cd, Cu, Ni, and Zn). Results indicated that the concentrations of most PTEs were lower than their local soil background values, except for Hg and Cd, which surpassed the background contents by 6.8 and 1.1 times, respectively. The I geo and PLI outcomes demonstrated a relatively low level of Hg contamination. Hg was the most hazardous elements with the mean ecological risk factor of 273.88. The Hazard Index (HI) values for PTEs were computed at 0.20 and 0.46 for adults and children, respectively, indicating that neither group was at a non-carcinogenic risk. Through the utilization of source identification methods, this study identified three predominant sources responsible for PTEs in the area: natural geogenic sources, anthropogenic sources and atmospheric deposition inputs. The findings of this study provide a robust scientific foundation for the management of the ecological environment security of rivers in the QTP. [Display omitted] [ABSTRACT FROM AUTHOR]

Trace elements contamination in estuarine and bay ecosystems has become a serious problem, especially in bays with frequent aquaculture activities. To explore the pollution risk, sources and trends of pollution trace elements in Dongshan Bay, a typical aquaculture bay in China, the concentration and spatial distribution of seven trace elements in surface sediments were investigated. In this study, Zn was the element with the highest content in surface sediments, followed by Pb and Cr, while Cd was the lowest, but the average concentrations of Cd and Hg exceeded the regional background values. High levels of trace elements were distributed in estuaries and aquaculture areas, which were illustrated also by the SOM model. An evaluation of the pollution load index (PLI), geo-accumulation index (I geo) and potential ecological risk index (PERI) demonstrated that Cd and Hg were the principal pollution elements and ecological risk factors in the surface sediments of the Bay. A positive matrix factorization model (PMF) revealed that the main sources of trace elements were natural sources, petrochemical industry and fossil fuel combination emissions, use of agricultural fertilizer, and industrial and agricultural sewage discharge. Comparative analysis found that since 2008, the mean content of Cu, Pb, Zn, and As have decreased significantly, while the content of Cd, Hg, and Cr have increased significantly. This information will help marine management efforts in taking effective measures to prevent environmental risks caused by trace elements pollution, especially related to aquaculture. [ABSTRACT FROM AUTHOR]

• A multi-leveled ESP was constructed to help with large-scale ecological conservation. • This ESP can enhance synergistic conservation across scales (regions, basins, and nations). • Five key ecosystem services focused by Sustainable Development Goal 15 were used to identify ecological sources. Serious ecological crises have emerged in the Asian Water Tower region (17 countries centered on the Qinghai-Tibetan Plateau), making it a major priority and challenge for Asian and even global ecological conservation efforts. Constructing a multi-leveled ecological security pattern (ESP) based on the synergies among multiple ecosystem services (ESs) for this region can enhance the structural integrity, functional stability, and spatial connectivity of ecosystems. Therefore, based on a series of GIS spatial analysis methods, the minimum cumulative resistance model, and the analytic hierarchy process, this study measured the importance of five key ESs focused by Sustainable Development Goal 15 (including water conservation, carbon sequestration, sand fixation, soil conservation, and biodiversity conservation); and took fishnet scale as data calculation unit to construct a hierarchical ESP (including three levels of ecological sources and corridors) to provide evidence-based support for identifying and prioritizing synergistic conservation actions across scales (regions, nations, and basins). Overall, the ESP included a total of 534 sources and 656 corridors. Some key conservation obstacles in the region (e.g., edge effects and several human activities) and corresponding priority actions are provided, such as integrating the ESPs into long-term planning, enhancing the conservation and the restoration of both the extent and the quality of forests (e.g., increasing tree species richness), and increasing collaboration across scales for resource mobilization and synergistic land use. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) is the largest reservoir of organic carbon in the terrestrial ecosystem, and is an effective mean of enhancing crop production in the irrigated area of the arid and semi-arid regions. Understanding long-term changes in composition of SOM under irrigation from sediment-laden Yellow River water is essential to manage sustainability issues in the agro-ecosystem. A total of 45 soils, including 39 of irrigated fields differing in irrigation history and 6 of non-cultivated and non-irrigated natural fields as the control, were sampled at 0–20 cm depth. The soil was analyzed for total SOC content, partitioning of light (LFOM) and heavy (HFOM) fraction organic matter based on NaI solution density of 1.7 g m 3 and for particle size distribution. Compared to the non-irrigated and non-cultivated control soil, the LFOM and HFOM in irrigated soils increased with the duration of irrigation though SOM existed dominantly as the heavy fraction. The soils irrigated for <50 years have overall lesser LFOM and HFOM and more sand compared to those with >50 years irrigation. Further, a positive relationship existed between the fine particle and the SOM or its fractions (negative relation with coarse particle) suggesting either SOM accumulated as fine particles or the fine mineral particles better preserved SOM. In addition, field soil moisture at the time of sampling during October 2009 correlated with HFOM ( p  < 0.001) and LFOM ( p  < 0.01). The study suggested that the long-term irrigation with water diverted from Yellow River increased fine particle, SOC and the light and heavy fraction in the Ningxia Irrigation Zone. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rare earth elements levels in hair were high in smelting and mining area. • Cerium contents in hair decreased with increasing age of children in smelting area. • Age and location were more important than sex affecting rare earth elements in hair. The long-term and large-scale mining of rare earth minerals may lead to an accumulation of rare earth elements (REEs) in the environment, posing potential health risks to residents. We collected scalp hair (n = 254) from residents of a smelting area, a mining area, and a reference area to clarify human exposure to REEs. The contents of 15 REEs investigated in human hair samples were notably higher in the mining and smelting areas than in the reference area. Significant differences between some REEs were observed between the mining and smelting areas, for instance, cerium (Ce), dysprosium, and praseodymium. In the study areas, exposure to different sources of REEs may be one of the factors that contributed to the variations of REE correlations and clusters in human hair. Furthermore, in the smelting area, Ce contents in hair decreased with increasing age of children. However, Ce contents in the hair of adults increased with age. In contrast, Ce accumulation continuously increased in the reference area residents' hair with age. Regression results indicated that age and location were more important than sex when considering the influence on REE accumulation in residents' hair. The results of this study may help policymakers to implement guidelines to alleviate residents' exposure to REE in mining and smelting areas. [ABSTRACT FROM AUTHOR]

Phosphorus and nitrogen pollutions from agricultural non-point source put heavy burden on water environment. Total nitrogen (TN), total phosphorus (TP) and ammonia nitrogen (NH 3 -N) are important pollutants in the study of agricultural non-point source pollution. This study presents a technical system that accurately calculated the coefficient of pollutants (TN, NH 3 -N and TP) entering water to grasp the situation of agricultural non-point source pollution. The system used for coefficient calculation is based on a main framework of driving factor-transmission factor-infiltration factor-interception factor, incorporating critical impacting factors including rainfall, topography, surface runoff, underground runoff, and interception factors. The coefficient was calculated by selecting typical units and extrapolated to the main stream area of the upper reaches of the Yellow River. Our study provides reference and practical basis for the development and application of coefficient model. It provides enlightenment for the calculation of agricultural non-point source pollutants. [ABSTRACT FROM AUTHOR]

Rare earth mine tailing dumps are environmental hazards because tailing easily leaches and erodes by water and wind. To assess the influence of mine tailing on the geochemical behavior of rare earth elements (REEs) in soil, sixty-seven surface soil samples and three soil profile samples were collected from different locations near China's largest rare earth mine tailing. The total concentration of REEs in surface soils ranged from 156 to 5.65 × 104 mg·kg−1 with an average value of 4.67 × 103 mg·kg−1, which was significantly higher than the average value in China (181 mg·kg−1). We found obvious fractionation of both light and heavy REEs, which was supported by the North American Shale Composite (NASC) and the Post-Archean Average Australian Shale (PAAS) normalized concentration ratios calculated for selected elements (LaN/YbN, LaN/SmN and GdN/YbN). A slightly positive Ce anomaly and a negative Eu anomaly were also found. For all 14 REEs in soils, enrichment was intensified by the mine tailing sources and influenced by the prevailing wind. [ABSTRACT FROM AUTHOR]

Decades of intensifying human activities have caused dramatic changes in land use and land cover (LULC) in the ecologically fragile areas of the Qinghai-Tibet Plateau, which have led to significant changes in ecosystem service value (ESV). Taking the ecologically fragile Sanjiangyuan region of the Qinghai-Tibet Plateau as the research object, we focused on understanding the impact of LULC changes on the Sanjiangyuan's landscape pattern and its corresponding ESV, which was combined with a Markov-Plus model to predict LULC changes in 2030. The results showed: (1) from 2000 to 2020, the LULC of Sanjiangyuan has changed to varying degrees, respectively. In the central and southern regions where animal husbandry is the mainstay activity, the area of grass land converted to bareland had expanded; (2) from 2000 to 2010, the total regional ESV increased sharply. However, the total amount of ESV decreased from 2010 to 2020; (3) the overall ESV in the study area was observed to be trending down and is expected to decrease by approximately 4.25 billion CNY by 2030; (4) the fragmentation and complexity of regional landscape patterns will negatively affect local ecosystem stability and biodiversity. Overall, there is a strong temporal and spatial correlation between LULC and ESV. This study will provide a reference for the local government to provide targeted and sustainable land management policies, thereby promoting the improvement of the Qinghai-Tibet Plateau regional ecology value. • ESV in ecologically fragile areas was affected by human activities. • ESV had strong spatial and temporal differences in Sanjiangyuan region. • Bareland and artificial surface had expanded in Sanjiangyuan region in the past few decades. • LULC combined with landscape index can explain ESV spatiotemporal changes. [ABSTRACT FROM AUTHOR]

Effects of landscape patterns or topographic features on the river water environment have been broadly studied to control non-point source (NPS) pollution and to cut off potential pathways for pollutants to affect human health. However, spatio-temporal dynamics and scale effects with respect to the impact of landscape patterns and topographic features on the aquatic environment over successive years have not been elucidated. In this study, water quality parameters and land cover data for three consecutive years mainly in Tangshan City, located in the northeast of the Haihe River Basin, China, were obtained to determine the associations between landscape patterns and topographic features with the water environment. Results indicated that seasonal differences in dissolved oxygen (DO) and total nitrogen (TN) were significant (p < 0.001), and spatial variation was generally observed for each water quality parameter. Redundancy analysis revealed that landscape patterns and topographic features have different impacts on the aquatic environment as seasonal spans and spatial scales change. Overall, the best explanatory variables explained an average of 58.6% of the variation in water quality at various spatial scales over the two seasons. Topographic features made a greater contribution to river water quality changes at the buffer scale; conversely, at the catchment scale, water quality changes stemmed primarily from differences in landscape composition and configuration. The landscape shape index of cropland (LSIcrop) was an important factor influencing seasonal river water quality changes at various spatial scales. These results suggest that considering landscape connectivity at distinct spatial scales could enhance the understanding of the alteration of hydrological processes across multiple topographic features, which in turn has an impact on seasonal river water. [ABSTRACT FROM AUTHOR]

The Qinghai Lake, a quintessential representative of the world's plateau inland lakes, has garnered much scrutiny from scholars for its current status of potentially toxic elements (PTEs) pollution. Hence, this study investigated the concentrations and distribution of seven PTEs i.e., Co, Cr, Cu, Ni, Pb, Zn and V. Furthermore, the potential ecological risk index (RI), self-organizing maps (SOM), correlation analysis and positive matrix factorization (PMF) were used to explore the level of risk and sources of pollution in the study area. The study revealed that: (1) the contents of PTEs in Qinghai Lake sediments were lower than other regions, yet 25.0% of Pb and 19.4% of Zn remained above background values, and the spatial distribution was more heterogeneous; (2) the high ecological risk in the sediment was spread mainly in the downstream of the estuary and the vicinity of tourist sites, where the ecological risk index of Pb was the maximum; (3) correlation and model analysis showed that the seven PTEs were homologous, and besides natural sources, transportation, mixed agricultural cultivation and coal-fired sources were presumed to be the main anthropogenic sources of disturbance. In the midst of rapid economic development, environmental pollution of the Qinghai Lake should be strictly controlled to avoid increased risks. [ABSTRACT FROM AUTHOR]

Potentially toxic elements (PTEs) in seawater and sediments may be amplified along the aquatic food chain, posing a health threat to humans. This study comprehensively analyzed the concentrations, distribution, potential sources, and health risk of 7 PTEs in multimedia (seawater, sediment and organism) in typical subtropical bays in southern China. The results indicated that Zn was the most abundant element in seawater, and the average concentration of Cd in sediment was 3.93 times higher than the background value. Except for As, the seasonal differences in surface seawater were not significant. The content of Zn in fishes, crustacea, and shellfish was the highest, while the contents of Hg and Cd were relatively low. Bioaccumulation factor indicated that Zn was a strongly bioaccumulated element in seawater, while Cd was more highly enriched by aquatic organisms in sediment. According to principal component analysis (PCA), and positive matrix factorization (PMF), the main sources of PTEs in Quanzhou Bay were of natural derivation, industrial sewage discharge, and agricultural inputs, each contributing 40.4 %, 24.2 %, and 35.4 %, respectively. This study provides fundamental and significant information for the prevention of PTEs contamination in subtropical bays, the promotion of ecological safety, and the assessment of human health risk from PTEs in seafood. [Display omitted] • Potentially toxic elements in the seawater, sediment and organism were monitored. • Sediment was moderately polluted by PTEs, especially for Cd. • Most abundant element in marine organisms is Zn, and highest excess rate was As. • The sources of PTEs were natural sources, industrial and agricultural activities. [ABSTRACT FROM AUTHOR]

The environmental pollution caused by mineral exploitation and energy consumption poses a serious threat to ecological security and human health, particularly in resource-based cities. To address this issue, a comprehensive investigation was conducted on potentially toxic elements (PTEs) in road dust from different seasons to assess the environmental risks and influencing factors faced by Datong City. Multivariate statistical analysis and absolute principal component score were employed for source identification and quantitative allocation. The geo-accumulation index and improved Nemerow index were utilized to evaluate the pollution levels of PTEs. Monte Carlo simulation was employed to assess the ecological-health risks associated with PTEs content and source orientation. Furthermore, geo-detector and random forest analysis were conducted to examine the key environmental variables and driving factors contributing to the spatiotemporal variation in PTEs content. In all PTEs, Cd, Hg, and Zn exhibited higher levels of content, with an average content/background value of 3.65 to 4.91, 2.53 to 3.34, and 2.15 to 2.89 times, respectively. Seasonal disparities were evident in PTEs contents, with average levels generally showing a pattern of spring (winter) > summer (autumn). PTEs in fine road dust (FRD) were primarily influenced by traffic, natural factors, coal-related industrial activities, and metallurgical activities, contributing 14.9–33.9 %, 41.4–47.5 %, 4.4–8.3 %, and 14.2–29.4 % to the total contents, respectively. The overall pollution and ecological risk of PTEs were categorized as moderate and high, respectively, with the winter season exhibiting the most severe conditions, primarily driven by Hg emissions from coal-related industries. Non-carcinogenic risk of PTEs for adults was within the safe limit, yet children still faced a probability of 4.1 %−16.4 % of unacceptable risks, particularly in summer. Carcinogenic risks were evident across all demographics, with children at the highest risk, mainly due to Cr and smelting industrial sources. Geo-detector and random forest model indicated that spatial disparities in prioritized control elements (Cr and Hg) were primarily influenced by particulate matter (PM 10) and anthropogenic activities (industrial and socio-economic factors); variations in particulate matter (PM 10 and PM 2.5) and meteorological factors (wind speed and precipitation) were the primary controllers of seasonal disparities of Cr and Hg. [Display omitted] • High accumulation of Cd, Hg and Zn was found in fine road dust. • The overall eco-risk of potentially toxic elements was high, especially in winter. • Carcinogenic risks to children need to be prioritized, notably during the summer. • Cr and Hg are priority control elements. • Environmental factors significantly influence the spatial pattern of Cr and Hg. [ABSTRACT FROM AUTHOR]

The accurate identification of sources for soil heavy metal(loid) is difficult, especially for multi-functional parks, which include multiple pollution sources. Aiming to identify the apportionment and location of heavy metal(loid)s pollution sources, this study established a method combining principal component analysis (PCA), Geodetector, and multiple linear regression of distance (MLRD) in soil and dust, taking a multi-functional industrial park in Anhui Province, China, as an example. PCA and Geodetector were used to determine the type and possible location of the source. Source apportionment of individual elements is achieved by MLRD. The detection results quantified the spatial explanatory power (0.21 ≤ q ≤ 0.51) of the potential source targets (e.g., river and mining area) for the PCA factors. A comparative analysis of the regression equation (Model 1 and Model 3) indicated that the river (0.50 ≤ R 2 ≤0.78), main road (0.47 ≤ R 2 ≤ 0.81), and mine (0.14 ≤ R 2 ≤ 0.92) (p < 0.01) were the main sources. Different from the traditional source apportionment methods, the current method could obtain the exact contributing sources, not just the type of source (e.g., industrial activities), which could be useful for pollution control in areas with multiple sources. [Display omitted] • PCA- Geodetector-MLRD was used to determine the location of the sources, not just the type of source. • The river, main road, mining area, metal plant, and community can significantly explain the PCA factors. • A distance-based prediction model for heavy metal concentration was established and its effectiveness was verified. [ABSTRACT FROM AUTHOR]

The conflict between industrial development and environmental pollution is global. This study quantitatively analyzes the temporal and spatial changes, spatial effects and determinants of industrial pollution discharge in the Yangtze River Economic Belt through two main indicators: wastewater and SO 2. Analyze the spatial coupling relationship between industrial agglomeration and pollution emission and the characteristics of industrial structure in different regions. The analysis shows that industrial emissions in the Yangtze River Economic Belt first increased and then decreased during the period 2003–2019. Industrial pollution spread from large to small and medium cities and shifted from downstream to upstream. Moreover, a positive correlation exists between industrial pollution discharge and per capita GDP, secondary industry proportion, population density, and energy use. Meanwhile, scientific and technological progress and environmental regulations are associated with industrial pollution reduction. Since the Yangtze River Economic Belt was still in the industrialization stage and had not yet reached a turning point on the Environmental Kuznets Curve. The "pollution refuge" phenomenon was evident in the Belt, where underdeveloped areas in the central and western regions accommodated portions of highly polluting industries from the eastern areas through "regional competition" and "policy depression." The industrial agglomeration and pollution antagonistic zones were dominated by polluting industries; environmental risks were greatest in these areas. The upstream and downstream of the YREB play the negative and positive environmental externalities of industrial agglomeration, respectively. Thus, differential control measures should be formulated according to different regions, industrial pollutants, and polluting industries to improve environmental quality. • Industrial emissions first increased and then decreased during the period 2003–2019. • Industrial pollution spread from large to small and medium cities and shifted from downstream to upstream. • Economic development and population agglomeration increased pollution. • The "crowding effect" of industrial agglomeration intensifies the emission of pollutants. [ABSTRACT FROM AUTHOR]

A field experiment was performed from 2003 to 2008 to evaluate the effects of tillage system and nitrogen management regimes on crop yields and nitrate leaching from the fluvo-aquic soil with a winter wheat ( Triticum aestivum L.)-maize ( Zea mays L.) double-cropping system. The tillage systems consisted of conventional tillage ( CT) and no-tillage ( NT). Three nitrogen management regimes were included: 270 kg N ha−1 of urea for wheat and 225 kg N ha−1 of urea for maize (U), 180 kg N ha−1 of urea and 90 kg N ha−1 of straw for wheat and 180 kg N of urea and 45 kg N ha−1 of straw for maize (S), 180 kg N ha−1 of urea and 90 kg N ha−1 of manure for wheat and 180 kg N ha−1 of urea and 45 kg N ha−1 of manure for maize (M). An array of tension-free pan lysimeters (50 cm × 75 cm) were installed (1.2 m deep) to measure water flow and [ABSTRACT FROM AUTHOR]

An extensive soil survey was conducted to study pollution sources and delineate contamination of heavy metals in one of the metalliferous industrial bases, in the karst areas of southwest China. A total of 597 topsoil samples were collected and the concentrations of five heavy metals, namely Cd, As (metalloid), Pb, Hg and Cr were analyzed. Stochastic models including a conditional inference tree (CIT) and a finite mixture distribution model (FMDM) were applied to identify the sources and partition the contribution from natural and anthropogenic sources for heavy metal in topsoils of the study area. Regression trees for Cd, As, Pb and Hg were proved to depend mostly on indicators of anthropogenic activities such as industrial type and distance from urban area, while the regression tree for Cr was found to be mainly influenced by the geogenic characteristics. The FMDM analysis showed that the geometric means of modeled background values for Cd, As, Pb, Hg and Cr were close to their background values previously reported in the study area, while the contamination of Cd and Hg were widespread in the study area, imposing potentially detrimental effects on organisms through the food chain. Finally, the probabilities of single and multiple heavy metals exceeding the threshold values derived from the FMDM were estimated using indicator kriging (IK) and multivariate indicator kriging (MVIK). The high probabilities exceeding the thresholds of heavy metals were associated with metalliferous production and atmospheric deposition of heavy metals transported from the urban and industrial areas. Geostatistics coupled with stochastic models provide an effective way to delineate multiple heavy metal pollution to facilitate improved environmental management. [ABSTRACT FROM AUTHOR]

SPE using a cross-linked starch-based polymer ( CSMDI) as an adsorbent for the determination of four nitrophenols at trace levels from aqueous solution was investigated. The CSMDI was synthesized from native starch using 4,4′-methylenebisphenyldiisocyanate as a cross-linking agent in dry DMF. Parameters affecting the extraction efficiency including the pH of the water sample, type of eluent and its volume, flow rate, sample volume, and methanol content were investigated and optimized. The optimized results exhibited excellent linear relationships ( R2 > 0.995) for all the nitrophenols over the range of 2.0-200 ng/mL, with the RSD values in the range of 2.9-5.7% ( n = 5). The LODs ranged from 0.08-0.34 ng/mL ( S/ N = 3) for the four nitrophenols tested under optimum conditions. The developed method has been successfully applied for the analysis of several real environmental water samples including tap, river, and reservoir water. These results indicated that the CSMDI had a tremendous potential for the enrichment and determination of nitrophenols at trace levels in environmental water samples. [ABSTRACT FROM AUTHOR]

The research was carried out to examine the pollution characteristics, ecological risk, and origins of seven heavy metals (Hg, As, Pb, Cu, Cd, Zn, and Ni) in 51 sediment samples gathered from 8 rivers located on the Qinghai-Tibet Plateau (QTP) in China. The contents of Hg and Cd were 5.0 and 1.1 times higher than their background values, respectively. The mean levels of other measured heavy metals were below those found naturally in the local soil. The enrichment factor showed that the study area exhibited significantly enriched Hg with 70.6% sampling sites. The Cd contents at 19.6% of sampling sites were moderately enriched. The other sampling sites were at a less enriched level. The sediments of all the rivers had a medium level of potential ecological risk. Hg was the major ecological risk factor in all sampling sites, followed by Cd. The findings from the positive matrix factorization (PMF) analysis shown agricultural activities, industrial activities, traffic emissions, and parent material were the major sources. The upper, middle, and low reaches of the Quanji river had different Hg isotope compositions, while sediments near the middle reaches were similar to the δ202Hg of the industrial source. At the upstream sampling sites, the Hg isotope content was very close to the background level. The results of this research can establish a strong scientific sound to improve the safety of the natural circumstances of rivers on the QTP. • Accumulation of heavy metals in river sediments of QTP was observed. • Mercury was the main pollution element in river sediments. • The sediments of all rivers were at medium potential ecological risk. • The source identification of heavy metals was studied using PMF and Hg isotope. [ABSTRACT FROM AUTHOR]

Ozone (O3) pollution has a profound impact on human health, vegetation development, and the ecological environment, making it a critical focus of global academic research. In recent years, O3 pollution in China has been on a steady rise, with ozone emerging as the sole conventional pollutant to consistently increase in concentration without any decline. This study conducted a quantitative analysis of O3 concentrations across 367 Chinese cities in 2019, examining spatial autocorrelation and local clustering of O3 levels, and investigated the diverse relationships between human activity factors and O3 concentration. The seasonal fluctuation of O3 exhibited the “M-type” pattern, with peak concentrations in winter and the lowest levels in summer. The center of O3 pollution migrated southeastward, with the area of highest concentration progressively shifting south along the eastern coast. Moreover, O3 concentration showed a strong positive correlation with population density, road freight volume, and industrial emissions, suggesting that human activities, vehicle emissions, and industrial operations are significant contributors to O3 production. The results provide comprehensive information on the characteristics, causes, and occurrence mechanism of O3 in Chinese cities that can be utilized by global government departments to formulate strategies to prevent and control O3 pollution. [ABSTRACT FROM AUTHOR]

Coal burning may enhance human exposure to the natural radionuclides that occur around coal-fired power plants (CFPP). In this study, the spatial distribution and hazard assessment of radionuclides found in soils around a CFPP were investigated using statistics, geostatistics, and geographic information system (GIS) techniques. The concentrations of 226Ra, 232Th, and 40K in soils range from 12.54 to 40.18, 38.02 to 72.55, and 498.02 to 1126.98Bqkg−1, respectively. Ordinary kriging was carried out to map the spatial patterns of radionuclides, and disjunctive kriging was used to quantify the probability of radium equivalent activity (Raeq) higher than the threshold. The maps show that the spatial variability of the natural radionuclide concentrations in soils was apparent. The results of this study could provide valuable information for risk assessment of environmental pollution and decision support. [Copyright &y& Elsevier]