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Two kinds of cross-linked starch polymers were synthesized and used as adsorbent materials for the adsorption of o-nitrophenol (o-NP), p-nitrophenol (p-NP), 2,4-dinitrophenol (2,4-DNP) and 2-s-butyl-4,6-dinitrophenol (DNBP) from aqueous solutions. Results from adsorption experiments showed that the polymer 1 prepared by 4,4′-methylene-bis-phenyldiisocyanate (MDI) as cross-linking agent exhibited higher adsorption behaviors than that of the polymer 2 prepared by hexamethylene diisocyanate (HMDI). Equilibrium and thermodynamic of four nitrophenols on polymer 1 were further studied. Analyzed experimental data showed that the Freundlich model fitted the isotherm data better than the Langmuir model of the four nitrophenols onto polymer 1. The thermodynamics for the adsorption of the nitrophenols on polymer 1 were estimated in the range of 303–333 K. It has been found that the values of Gibbs free energy (ΔG) became more negative with decreasing temperature, which indicated that the adsorption process was more favorable at low temperature. [ABSTRACT FROM PUBLISHER]

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]

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]

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]

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]

Castanea mollissima BL (chestnut) is a kind of food with a unique flavor and high nutrition, which people pursue worldwide. As China is the birthplace of chestnut, there are many older chestnut trees all over the country. However, the nutritional value of the fruits of these old chestnut trees is not clear now. This study first assessed the nutritional value of old chestnut fruits (10 years, 100 years, 300 years, 500 years, 700 years and 900 years) in an old chestnut garden in Huairou, Beijing, highlighting the calcium, iron, zinc, selenium, amino acids and fatty acids. The age of all chestnut trees sampled was certified by Forestry Bureau of Beijing. These findings have revealed significant differences in the nutrient components of chestnuts with different years. The 10-year and 700-year groups have higher Zn, Se, and amino acid levels. Besides, the 700-year group has relative higher level of Ca and Fe and lower ratio of saturated fatty acid/unsaturated fatty acid. We also demonstrated that 700-year-old chestnuts have the highest nutrient value. This study provided a basis for establishing product quality standards for old chestnut trees and laid the foundation for further developing and protecting old chestnut in Beijing and even in the world. [ABSTRACT FROM AUTHOR]

Coal-fired industrial boilers (CFIBs) are critical anthropogenic contributors of heavy metals (HMs) because of their high coal consumption and complicated air pollution control facilities (APCDs). This study explored the flows of Hg, As, Cd, Cr, and Pb in CFIBs at regional scale by establishing a boiler-level HMs inflow-outflow inventory. The results indicate that large-capacity CFIBs (≥ 65 t/h) are the leading contributors to HMs inflows. The inflow intensities of HMs in the provinces exhibited three classes of clustering characteristics. Significant regional heterogeneity was characterized by the distribution of HMs inflows and outflows, with higher HMs inflows and outflows in the northern and east-central coastal areas. However, the relatively low synergistic control efficiency of Cd in Northwest China resulted in a higher contribution of waste than inflow. The wastes generated during the operation of CFIBs are the major outflows of HMs. Hg was observed to have the highest outflow of atmospheric emissions owing to its high volatility. In addition, significant differences in the magnitude of HM outflow were identified among the provinces. The application of efficient APCDs contributes significantly to the partitioning of HMs into waste flows, thereby decreasing regional atmospheric emissions. [Display omitted] • CFIBs with a capacity of ≥ 65 t/h are the dominant contributors of HMs inflows. • Northern and central-eastern regions are characterized by higher HMs emissions. • Fly ash and slag are the leading outflows of HMs in CFIBs. • PM control devices contribute the most to the flow of HMs in waste. • Higher atmospheric emission outflow is observed for Hg in CFIBs. [ABSTRACT FROM AUTHOR]

• The NANI peaked in 2020, representing a 54.41% increase compared to 1990. • The proportion of food/feed nitrogen input to NANI was the highest, reaching 62.30%. • The spatial pattern of NANI exhibited a decreasing trend from east to west and from north to south. • The spatiotemporal changes of NANI are related to the intensity of human activities. • Population density and GDP were the most influential socioeconomic factors impacting NANI. The issue of global nitrogen overload is widely acknowledged as a pressing concern, with excessive nitrogen input resulting from human activities posing a significant threat to regional security. Notably, China emerges as a prominent contributor, exhibiting one of the highest anthropogenic nitrogen inputs worldwide. This study employs the Net Anthropogenic Nitrogen Input (NANI) as a pivotal tool to scrutinize the spatial and temporal patterns of nitrogen input in China spanning from 1990 to 2020. The total NANI reached its zenith in 2020 at 723,378.80 kg·km−2·yr−1, marking a noteworthy 54.41 % increase from 1990. Among the various nitrogen sources, food/feed nitrogen input prevails, constituting 62.30 % of NANI, followed by atmospheric nitrogen deposition at 30.05 %. In less developed regions, primary contributors to NANI include nitrogen fertilizer application and crop nitrogen fixation. The spatial distribution of NANI exhibits a diminishing trend from east to west and north to south. Conducting a quantitative analysis, this study elucidates the impact of socioeconomic factors on NANI in China. Population density (r = 0.97) and GDP (r = 0.91) emerge as primary influencers, with agricultural factors such as livestock breeding (r = 0.70), grain production (r = 0.40), and fertilizer application (r = 0.65) following suit. In addressing the environmental challenges posed by excessive nitrogen, future mitigation strategies should prioritize enhancements in manure management practices and the implementation of pollution reduction facilities. [ABSTRACT FROM AUTHOR]

Identifying driving factors is of great significance for understanding the mechanisms of soil pollution. In this study, a data processing method for driving factors was analyzed to explore the genesis of Arsenic (As) pollution in mining areas. The wind field that affects the atmospheric diffusion of pollutants was simulated using the standard k − ε model. Machine learning and GeoDetector methods were used to identify the primary driving factors. The results showed that the prediction performances of the three machine learning models were improved after data processing. The R2 values of random forest (RF), support vector machine, and artificial neural network increased from 0.45, 0.69, and 0.24 to 0.55, 0.76, and 0.52, respectively. The importance of wind increased from 20.85% to 26.22%. The importance of distance to the smelter plant decreased from 43.26% to 33.19% in the RF model. The wind's driving force (q value) increased from 0.057 to 0.235 in GeoDetector. The average value of historical atmospheric dust reached 534.98 mg/kg, indicating that atmospheric deposition was an important pathway for As pollution. The outcome of this study can provide a direction to clarify the mechanisms responsible for soil pollution at the mining area scale. [Display omitted] • Data processing method of driving factors at mining area scale was proposed. • Prediction performances of models were significantly improved after data processing. • Analysis of dust fall and production process supported the prediction results. • Atmospheric dust fall (historically) caused As pollution through wind transmission. [ABSTRACT FROM AUTHOR]

Contamination, hazard level and source of 10 widely concerned potentially toxic metal(loid)s (PTMs) Co, As, Pb, Cr, Cu, Zn, Ni, Mn, Ba, and V in fine dust with particle size below 63 μm (FD63) were investigated to assess the environmental quality of college campuses and influencing factors. PTMs sources were qualitatively analyzed using statistical methods and quantitatively apportioned using positive matrix factorization. Probabilistic contamination degrees of PTMs were evaluated using enrichment factor and Nemerow integrated enrichment factor. Eco–health risk levels of content–oriented and source–oriented for PTMs were evaluated using Monte Carlo simulation. Mean levels of Zn (643.8 mg kg−1), Pb (146.0 mg kg−1), Cr (145.9 mg kg−1), Cu (95.5 mg kg−1), and Ba (804.2 mg kg−1) in FD63 were significantly larger than soil background values. The possible sources of the concerned PTMs in FD63 were traffic non–exhaust emissions, natural source, mixed source (auto repair waste, paints and pigments) and traffic exhaust emissions, which accounted for 45.7%, 25.4%, 14.5% and 14.4% of total PTMs contents, respectively. Comprehensive contamination levels of PTMs were very high, mainly caused by Zn pollution and non–exhaust emissions. Combined ecological risk levels of PTMs were low and moderate, chiefly caused by Pb and traffic exhaust emissions. The non–cancer risks of the PTMs in FD63 to college students fell within safety level, while the carcinogenic PTMs in FD63 had a certain cancer risks to college students. The results of source–specific health risk assessment indicated that Cr and As were the priority PTMs, and the mixed source was the priority pollution source of PTMs in FD63 from college campuses, which should be paid attention to by the local government. • Elevated Pb, Cr, Cu, Zn, and Ba were found in fine dust from college campuses. • Potentially toxic metal(loid)s had a certain cancer risks to college students. • Vehicle-related sources were the main anthropogenic sources of elevated metals. • Mixed source was the priority pollution source. • Cr and As were the priority pollutants. [ABSTRACT FROM AUTHOR]

Industrial wastewater discharge has become the main cause of water pollution in China. However, the spatial interaction mechanism between industrial structure and water pollution is still unclear. Accordingly, we evaluated and analyzed spatiotemporal changes of the agglomeration pattern of pollution-intensive industrial enterprises and the evolution of the water environmental pollution pattern, as well as the correlation between them. The study results show that the polluting industrial enterprises were located mainly along the Yangtze River and Taihu Lake Basin in southern Jiangsu in 2013 and 2018. However, we observed a spatial trend of pollution transfer to northern Jiangsu. The industrial water pollution discharge presents the distribution pattern of facing rivers, seas, lakes and cities. Papermaking and paper products industry are the leading factors of COD and NH 3 –N pollution, with explanatory power of 0.3666 and 0.6201 respectively. The spatial positive coupling effect between the concentration degree of polluting enterprises and the intensity of water environment pollution discharge is 94.95% of the region. The spatial agglomeration of polluting industrial enterprises is an important cause of water environment pollution. They promote and couple each other, proving the existence of "Pollution haven" and "Porter hypothesis". [Display omitted] • The polluting industrial enterprises are located mainly along the Yangtze River and Taihu Lake Basin. • Papermaking and paper products industry are the leading factors of COD and NH 3 –N pollution. • The spatial agglomeration of polluting industrial enterprises is a significant cause of water environment pollution. • This study proves the existence of "Pollution haven" and "Porter hypothesis". • This study fills the gap in the spatial response mechanisms of different industrial structures and pollutants. [ABSTRACT FROM AUTHOR]

Pteris vittata , as the firstly discovered arsenic (As) hyperaccumulator, has great application value in As-contaminated soil remediation. Currently, the genes involved in As hyperaccumulation in P. vittata have been mined continuously, while they have not been used in practice to enhance phytoremediation efficiency. Aiming to better assist the practice of phytoremediation, this review collects 130 studies to clarify the progress in research into the As hyperaccumulation process in P. vittata from multiple perspectives. Antioxidant defense, rhizosphere activities, vacuolar sequestration, and As efflux are important physiological activities involved in As hyperaccumulation in P. vittata. Among related 19 genes, PHT, TIP, ACR3, ACR2 and HAC family genes play essential roles in arsenate (AsⅤ) transport, arsenite (AsⅢ) transport, vacuole sequestration of AsⅢ, and the reduction of AsⅤ to AsⅢ, respectively. Gene ontology enrichment analysis indicated it is necessary to further explore genes that can bind to related ions, with transport activity, or with function of transmembrane transport. Phylogeny analysis results implied ACR2, HAC and ACR3 family genes with rapid evolutionary rate may be the decisive factors for P. vittata as an As hyperaccumulator. A deeper understanding of the As hyperaccumulation network and key gene components could provide useful tools for further bio-engineered phytoremediation. [Display omitted] • The latest As hyperaccumulating mechanisms of P. vittata were summarized. • Further exploration should be directed to PHT, ACR3, and MIP family. • ACR2, HAC and ACR3 family genes with rapid evolutionary rate could be more noticed. [ABSTRACT FROM AUTHOR]

Manure generated from livestock farming is currently the focus of attention of global scientific community. China's livestock manure is extremely rich with a high potential for heavy metal contamination. Here, data were collected for 2000–2018.6 from China's National Statistical Data, Elsevier, China National Knowledge Infrastructure and other literature databases and analyzed for "feed–feces–soil" chain of heavy metals. An integrated analysis was done to explore the reductive effect of existing technologies on heavy metals in cattle manure. Excessive addition of heavy metal elements to feed is widespread in China. High amounts of undigested heavy metals are excreted through animal manure. The study showed that spatial variability of heavy metal contents in cattle manure was extremely large. The excess cupper (Cu) was higher than that of zinc (Zn), and was higher in southern than in northern China. Chemical treatments were more effective than physical and biological ones in controlling heavy metal pollution. The optimal reduction ratios of the effective Zn and Cu contents were 21.72% and 33.11%, respectively. The Zn and Cu contents could be reduced by 1.96 × 107 and 5.92 × 106 kg per year, respectively. This could reduce the risks posed by heavy metals after manure-based fertilizer applications in crop cultivation. Image 1 • Additions of heavy metals to cattle feed are generally excessive in China. • The heavy metal contents' spatial variability in cattle manure was extremely large. • Excess of Cu was greater than that of Zn, being higher in southern than northern. • Optimal passivator's reduction ratio was up to 33.11% of the effective Cu contents. • The effective Zn contents may be reduced over 1.96 × 107 kg per year. [ABSTRACT FROM AUTHOR]

Environmental remediation of heavy metal-mining sites can improve human well-being through pollution risk control and improved ecosystem services. A cost-benefit dynamic analysis for the multiple stakeholders involved in the project can better explain the overall efficiency and provide guidance for further mine remediation. Taking Asia's largest monomeric realgar mine environmental remediation project (MER) as a case, we conducted, for the first time, a dynamic cost–benefit analysis for multiple stakeholders over a 60-year period regarding environmental risks, health risks and ecosystem services. The results show that by improving the environment and ecosystem, the payback period is expected to begin 5 years after the end of the project, with a benefit‒cost ratio of 2.71 by 2050. Local residents, the direct beneficiaries, receive 13.2% of the benefits, which come from agricultural soil remediation projects (66.6%) and health risk reduction (33.4%). The government, as an investor, receives 3.3% of the benefits. Downstream water users are the main beneficiaries, receiving 76.5% of the total benefits, mainly from the benefit of As-contaminated water purification (97.9%). Compensation from downstream beneficiaries for improved water might be channeled into sharing the burden of MER implementation. Notably, the intercropping remediation of hyperaccumulators and low-accumulation crops for agricultural soils in MER provides employment and sustainable agricultural income during and after remediation, respectively. This green and sustainable remediation model improves both the environment and the livelihood of residents and should be recommended for nearly one million mining sites worldwide. [Display omitted] • Green and sustainable industries improves the household livelihood in mining areas. • Downstream water users are the main beneficiaries of mine environmental remediation. • Improving downstream water quality and industrial drivers should be mainly considered. [ABSTRACT FROM AUTHOR]

The contamination of potentially toxic elements (PTEs) in road dust of large industrial cities is extremely serious. Determining the priority risk control factors of PTE contamination in road dust is critical to enhance the environmental quality of such cities and mitigate the risk of PTE pollution. The Monte Carlo simulation (MCS) method and geographical models were employed to assess the probabilistic pollution levels and eco-health risks of PTEs originating from different sources in fine road dust (FRD) of large industrial cities, and to identify key factors affecting the spatial variability of priority control sources and target PTEs. It was observed that in FRD of Shijiazhuang, a typical large industrial city in China, more than 97% of the samples had an INI > 1 (INI mean = 1.8), indicating moderately contaminated with PTEs. The eco-risk was at least considerable (NCRI >160) with more than 98% of the samples, mainly caused by Hg (E i (mean) = 367.3). The coal-related industrial source (NCRI (mean) = 235.1) contributed 70.9% to the overall eco-risk (NCRI (mean) = 295.5) of source-oriented risks. The non-carcinogenic risk of children and adults are of less importance, but the carcinogenic risk deserves attention. The coal-related industry is a priority control pollution source for human health protection, with As corresponding to the target PTE. The major factors affecting the spatial changes of target PTEs (Hg and As) and coal-related industrial sources were plant distribution, population density, and gross domestic product. The hot spots of coal-related industrial sources in different regions were strongly interfered by various human activities. Our results illustrate spatial changes and key-influencing factors of priority source and target PTEs in Shijiazhuang FRD, which are helpful for environmental protection and control of environmental risks by PTEs. [Display omitted] • Fine road dust has serious potentially toxic element pollution and eco-risks. • Hg is the main contributor of eco-risk of potentially toxic elements in fine dust. • The cancer risk mainly caused by As needs attention. • Identified coal-related industrial sources as a priority control factor. • Spatial aggregation reveals correlations of pollution source and environmental factors. [ABSTRACT FROM AUTHOR]

This study investigated the adsorption of sulfadiazine (SDZ) with four biochars prepared at 600, 700, 800 and 900 °C, and probed the potential rule connecting their chemical properties and adsorption capacities. Results showed that increasing the pyrolytic temperature, specific surface area, pore volume, aromaticity and aromatic cluster lateral size (L a) of biochar markedly improved its adsorption capacity for SDZ. The maximum adsorption capacities (q m) of biochar 600 , biochar 700 , biochar 800 and biochar 900 for SDZ were 3.44, 17.87, 86.13 and 206.03 mg g−1, respectively. The pyrolytic temperature of 700 °C was the key temperature for the graphite-like biochar preparation, beyond which the L a of biochar rapidly expanded. Compared with the pyrolytic temperature, specific surface area, pore volume and aromaticity of biochar, the L a values of the four biochars exhibited a good positive linear correlation with their q m , indicating for the first time that L a is an effective indicator to predict the adsorption capacity of graphite-like biochar. Density functional theory calculation further revealed that larger aromatic clusters could accommodate more SDZ molecules, and that the interaction among SDZ molecules in turn increased their binding energy with biochar. These findings in this study provide useful information for designing various efficient biochar adsorbents in the future. [Display omitted] • Four graphite-like biochars were prepared at different pyrolytic temperatures. • Graphitization degree of biochar dramatically increased as preparing above 700 °C. • The adsorption of sulfadiazine on the four biochars was examined. • Correlations between the properties and adsorption capacities of biochar were evaluated. • Aromatic cluster lateral size is an index to predict the adsorption capacity of biochar. [ABSTRACT FROM AUTHOR]

Considering the soil cadmium pollution problem, the Chinese government proposed to estimate the costs and practicality "to completely improve the soil quality by the middle of this century". This study analyzed the challenges in achieving this goal using biophysical data from 10 typical demonstration soil phytoextraction projects. The current annual phytoextraction efficiency was determined as 14.8–490 g ha−1 a−1 at 319 RMB g−1 cadmium. A total of 798 billion RMB and 5 years were required for remediation of cadmium contamination, which was 22 times the investment in soil remediation during 2016–2022. The break-even point of phytoextraction projects was 29 years. The heavy financial burden was considered the primary challenge in improving the environmental quality of such soil. The cost could be reduced by 5.5–35.3 % through optimization measures such as resourcefulness of hyperaccumulator harvests, large-scale breeding, and mechanized management. The break-even point could be shortened to 6–15 years by intercropping/rotating crops, contributing to the goal. Active exploration of phytoextraction efficiency—more efficient accumulators, optimized agronomic measures—is worth practicing. [Display omitted] • Analyzing challenges to remediation of cadmium-contaminated soil in China. • Heavy financial burden and long input-output balance cycle are the primary obstacles. • Proposing feasible measures to solve the soil cadmium problem in China. [ABSTRACT FROM AUTHOR]

Straw returning is a vital agronomic practice for soil organic carbon (SOC) sequestration and stabilization by changing the storage and fraction composition. Iron and aluminum (Fe/Al) oxides have a protective effect on SOC through adsorption and co-precipitation, which depends on the fraction composition of SOC itself, especially originated from externally added organic materials. However, the changes and interactions of SOC components and Fe/Al oxides in straw returning soil are not clearly understood. To evaluate the effect of straw returning on SOC composition and Fe/Al oxides, we have conducted an in situ field experiment for 10 yrs., which including five treatments: no rice and wheat straw returning (NRW, as control), total amount wheat straw returning (W), total amount rice straw returning (R), half amount rice and wheat straw returning (HRW), and total amount rice and wheat straw returning (TRW). The results showed that SOC and heavy fraction organic carbon (HFOC) increased under all five treatments, especially for R, HRW, and TRW treatments (P < 0.05). Compared with wheat straw returning, rice straw returning was more conducive to increasing the contents of SOC and its fractions, free Fe/Al oxides, complex aluminum oxides and the carbon utilization efficiency. Collectively, these properties were strongly affected by both the type and amount of straw returning. Soil organic carbon was significantly correlated with HFOC, water-soluble organic carbon, alkali-hydrolyzed nitrogen, available phosphorous, available potassium, and total nitrogen (P < 0.05). Of these, HFOC had the most significant effect on SOC and was vitally important for improving SOC sequestration and stability (P < 0.001). The increase of labile carbon fractions was more conducive to the absorption and utilization of nutrients by crops. Straw returning promoted the interaction between increasing organic matter and complex iron oxide (Fe c). This served to strengthen the protective effect of SOC, which increased the content of Fe c and stability of SOC, resulting in decreased soil pH. Taken together, these results highlight the importance of straw returning in promoting the storage and stability of SOC pool. Critically, rice straw returning can reduce soil pH and Fe c content, therefore could be considered as an ideal model for a rice-wheat rotation system. • Long-term straw returning increased the sequestration and stability of soil organic carbon by increasing heavy fractions. • Soil organic carbon fraction composition and Fe/Al oxides changed simultaneously with straw type and amount. • The effect of labile organic carbon of straw returning on Al oxides was greater than that of Fe oxides. • Rice straw returning has greater potential in improving soil organic carbon and soil properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni levels in hair were higher in adults in smelting area than others. • Cr was the highest in adults from mining area. • Cu was higher in hairs in mining area than smelting area. • People in mining and smelting areas were under higher Cu, Ni, Cd, and Pb risk. There is a growing concern about human health of residents living in areas where mining and smelting occur. In order to understand the exposure to the potentially toxic elements (PTEs), we here identify and examine the cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in scalp hair of residents living in the mining area (Bayan Obo, n = 76), smelting area (Baotou, n = 57) and a reference area (Hohhot, n = 61). In total, 194 hair samples were collected from the volunteers (men = 87, women = 107) aged 5–77 years old in the three areas. Comparing median PTEs levels between the young and adults, Ni levels were significantly higher in adults living in the smelting area while Cr was highest in adults from the mining area, no significant difference was found for any of the elements in the reference area. From the linear regression model, no significant relationship between PTEs concentration, log 10 (PTEs), and age was found. The concentrations of Ni, Cd, and Pb in hair were significantly lower in the reference area when compared to both mining and smelting areas. In addition, Cu was significantly higher in the mining area when compared to the smelting area. Factor analysis (FA) indicated that men and women from the smelting area (Baotou) and mining area (Bayan Obo), respectively, had different underlying communality of log10(PTEs), suggesting different sources of these PTEs. Multiple factor analysis quantilized the importance of gender and location when combined with PTEs levels in human hair. The results of this study indicate that people living in mining and/or smelting areas have significantly higher PTEs (Cu, Ni, Cd, and Pb) hair levels compared to reference areas, which may cause adverse health effects. Remediation should therefore be implemented to improve the health of local residents in the mining and smelting areas. [ABSTRACT FROM AUTHOR]

Natural vegetation has been proved to promote water purification in previous studies, while the relevant laws has not been excavated systematically. This research explored the relationships between vegetation cover and water quality indexes in Liaohe River Basin in China combined with self-organizing map (SOM) and geographically and temporally weighted regression (GTWR) innovatively and systematically based on the distributing heterogeneity of water quality conditions. Results showed that the central and northeast regions of the study area had serious organic and nutrient pollution, which needed targeted treatment. And SOM verified that high vegetation coverage with retention potential of organic and inorganic pollutants as well as nutrients improved water quality to some degree, while the excessive discharges of pollutants still had serious threats to nearby water environment despite the purification function of vegetation. GTWR indicated that the waterside vegetation was beneficial for dissolved oxygen increasing and contributed to the decreasing of organic pollutants and inorganic pollutants with reducibility. Natural vegetation also obsorbed nutrients like TN and TP to some degree. However, the retential potential of nitrogen and organic pollutants became not obvious when there were heavy pollution, which demonstrated that pollution sources should be controlled despite the purification function of vegetation. This study implied that natural vegetation purified water quality to some degree, while this function could not be revealed when there was too heavy pollution. These findings underscore that the pollutant discharge should be controlled though the natural vegetation in ecosystem promoted the purification of water bodies. • Natural vegetation had a certain promoting effect on water quality improvement. • Excessive pollution impacted water quality though the vegetation purification. • Nitrogen absorption of vegetation became not obvious with heavy nitrogen pollution. • Pollutants with similar distribution patterns needed the targeted treatment. • Construction of waterfront vegetation is a good method to improve water quality. [ABSTRACT FROM AUTHOR]

As the primary carrier of harmful elements, road sediment poses severe hazards to human health and ecological environment, especially in megacities. Based on the industrial cities in North China, this research focused on the multi-element features and the pollution levels, sources, and spatial distributions of trace metals in road sediment of Shijiazhuang. The mean levels of P (928.4 mg kg−1), S (1446.2 mg kg−1), Cl (783.9 mg kg−1), Br (5.3 mg kg−1), Na 2 O (2.0%), CaO (9.9%), Co (36.0 mg kg−1), Pb (38.0 mg kg−1), Cu (34.7 mg g−1), Zn (149.1 mg kg−1), Ba (518.1 mg kg−1), and Sr (224.9 mg kg−1) in road sediment were greater than their soil background values. Trace metals in most samples was moderately (75%) and heavily contaminated (15.6%). The industrial areas, congested roads, and residential areas in the northeast, middle and south of Shijiazhuang are the hotspots of trace metals pollution. A comprehensive analysis of trace metals sources indicated that Ni, V, Ga, Rb, Y, Sc, La, Ce, Zr, and Hf were mainly from natural source, which contributed to 34.2% of the total trace metals concentrations. Cu, Pb, Zn, Cr, Ba, Sr, and Mn primarily originated from mixed source, which accounted for 46.5%. Co principally came from building source, which accounted for 19.3%. This study shows that industrial discharges, construction dust and traffic emissions are the primary anthropogenic sources of trace metals in road sediment in the study area. [Display omitted] • P, S, Cl, Br, Na 2 O and TiO 2 in road sediment were higher than the background values. • Co, Cu, Pb and Zn were the key pollutants in road sediment. • The comprehensive pollution of trace metals in road sediment was moderate to heavy. • Industry, traffic and building activities are the key human sources of trace metals. [ABSTRACT FROM AUTHOR]

Water environment can be affected by multiple natural and human factors. This study aimed to explore the impacts on water quality from various driving factors including land use, landscape, social economy and climate in a typical basin of Beijing-Tianjin-Hebei Region combined with neural networks like self-organizing map and back propagation artificial neural network based on the water quality monitoring data. And redundancy analysis as well as gray correlation analysis were also adopted to explore the relationships between water quality and landscape indices as well as socioeconomic factors, respectively. The results showed that different land uses had different impacts on water quality. Agricultural additions in cropland had a great impact on surrounding water environment. The forest and grassland purified water to some degree, while the vegetation purification became weaker when there was serious pollution. The fragmentated landscape patches with high patch density caused by human activities also worsened water quality because its retention of pollutants was weakened. Besides, the per capita disposable income of rural residents and the per capita disposable urban income had the highest correlation degrees with most water quality indexes in all socioeconomic factors. In addition, temperature rise would promote dissolved oxygen consumption and eutrophication. Increasing precipitation brought pollutants into water via rainfall contains, nutrient transportation and soil erosion. The main conclusions were that both agricultural activities and urban development had impacts on water environment, and the vegetation purification became less obvious in heavily polluted areas. In addition, the rising temperature and precipitation disturbed water quality under the background of global warming. This study is helpful for water pollution management and it will give enlightenment for the water environment protection under the combining effects of human disturbance, economic development and climate change. [Display omitted] • The purification of grassland became weak when the pollution was too serious. • Fragmentated landscape is not conducive to the interception of pollutants. • Economic activities in rural and urban areas were closely related to water quality. • Increase of temperature or rainfall was not benefit for water environment. [ABSTRACT FROM AUTHOR]

Land-use change influences the fate of nutrient elements, including iron (Fe), and then threaten soil security. In this study, Fe forms and stable isotope composition (δ56Fe) in soils were investigated to identify the variations in the processes of Fe cycling during agricultural abandonment in a karst region of Southwest China. Soil δ56Fe compositions varied from −0.05‰–0.02‰ in croplands, 0.05‰–0.12‰ in abandoned croplands, to 0.30‰–0.80‰ in the native vegetation lands. In the croplands, Fe oxidation-precipitation process is considered as the main contributor to Fe migration and isotope fractionation, leading to a relatively enrichment of heavier Fe isotope in deeper soil layer. In the abandoned croplands and native vegetation lands, Fe isotope in the organic-rich layer (0–10 cm) was significantly lighter than that in subsurface layer (20–30 cm), mainly due to the recovery of soil organic carbon (SOC) and macro-aggregate after cropland abandonment. Moreover, the eluviation process mainly caused a decrease in soil Fe contents and enrichment of heavy Fe isotope in deeper soils (below 40 cm). The positive correlation between oxidized Fe and SOC contents suggested the accumulation of mobile Fe in soils after agricultural abandonment, which is beneficial for Fe uptake and assimilation by plants. This study suggests that agricultural abandonment significantly reduce soil Fe leaching loss and improve plant Fe supply by SOC accumulation in surface soil, which gives an environmental implication for the management of soil nutrients. • Land-use change influences the Fe forms and isotope compositions in soils. • Fe oxidation-precipitation is the main contributor to Fe isotope fractionation in cropland soils. • Agricultural abandonment significantly reduce soil Fe leaching loss in surface soil. [ABSTRACT FROM AUTHOR]