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Selenium (Se) has a dual nature, with beneficial and harmful effects on plants, essential for both humans and animals, playing a crucial role in ecosystem regulation. Insufficient Se in specific terrestrial environments raises concerns due to its potential to cause diseases, while excess Se can lead to severe toxicity. Thus, maintaining an optimal Se level is essential for living organisms. This review focuses first on Se transformation, speciation, and geochemical properties in soil, and then provides a concise overview of Se distribution in Chinese soil and crops, with a focus on the relationship between soil Se levels and parent materials. Additionally, this paper explores Se bioavailability, considering parent materials and soil physicochemical properties, using partial least squares path modeling for analysis. This paper aimed to be a valuable resource for effectively managing Se-enriched soil resources, contributing to a better understanding of Se role in ecosystems. [ABSTRACT FROM AUTHOR]

Chirality transformation is a basic, attractive, and important strategy for obtaining enantioenriched products with desired chiral elements. The reported chirality conversion reaction often involves the process from one type of chirality to another one. To better utilize the chirality transformation strategy for obtaining two or more products with different chiral elements in a single reaction, a new method of kinetic resolution accompanied by a chirality transformation protocol is proposed and successfully realized in this study. This process is used for the asymmetric oxidation of phenol compounds along with the kinetic resolution of oxaziridines. A wide scope of products, including axially chiral phenols, oxaziridines, and α-hydroxyl cyclic ketones were smoothly obtained in high levels of yields and enantioselectivities in the developed method. These products can be readily used for the synthesis of various types of chiral ligands, which are potential choices for other catalytic asymmetric reactions. [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 importance of ecosystem services (ESs) has been widely recognized and studied since 2000. However, research on the interactions (synergies and trade-offs) among ESs and hotspots of ESs is limited. This study focused on the Asian Water Tower (AWT) region (17 countries) and assessed the importance of five critical ESs by four quantitative models, analyzed the interactions among ESs, and identified hotspots of ESs using hotspot analysis. The results showed that the areas with “high importance” of the composite ESs accounted for 6.3% of the AWT region, and they were distributed mainly in mountain and coastal areas. Additionally, high synergies among the five ESs were observed in areas with “high importance” of the composite ESs, whereas poor synergies among ESs were found in areas with “relatively high importance” of the composite ESs. Furthermore, a total of 132 hotspot basins (28.4% of the AWT region) of the composite ESs were identified, and 23.2% of the hotspot basins were areas with “highly and relatively highly synergistic” ESs. The results provide evidence-based support for setting ecosystem protection goals, achieving win-win ESs, and improving ecosystem management efficiency. Overall, this study can deepen the understanding of the interactions and hotspots of ESs in the AWT region. [ABSTRACT FROM AUTHOR]

There is a great uncertainty in generation and formation of non-point source (NPS) pollutants, which leads to difficulties in the investigation of monitoring and control. However, accurate calculation of these pollutant loads is closely correlated to control NPS pollutants in agriculture. In addition, the relationships between pollutant load and human activity and physiographic factor remain elusive. In this study, a modified model with the whole process of agricultural NPS pollutant migration was established by introducing factors including rainfall driving, terrain impact, runoff index, leaching index and landscape intercept index for the load calculation. Partial least squares path modeling was applied to explore the interactions between these factors. The simulation results indicated that the average total nitrogen (TN) load intensity was 0.57 t km−2 and the average total phosphorus (TP) load intensity was 0.01 t km−2 in Chengdu Plain. The critical effects identified in this study could provide useful guidance to NPS pollution control. These findings further our understanding of the NPS pollution control in agriculture and the formulation of sustainable preventive measures. [ABSTRACT FROM AUTHOR]

Rural decline has become a global problem. To address this issue, the division of rural functions and identification of driving factors are important means of rural revitalization. Taking the town area as a unit, this study conducts a division and evolution analysis of rural regional functions in Jiangsu province in coastal China by constructing an evaluation system using the spatial econometric model to diagnose endogenous and exogenous driving factors of rural multifunction formation. The results show that the functions of agricultural supply and ecological conservation have decreased, while the functions of economic development and social security have increased. Agricultural production functions are concentrated in northern and central Jiangsu. The economic development function is mainly based on industrial development, and is the strongest in southern Jiangsu. Social security functions are concentrated in suburban area, county centers, and key towns. High-value areas of ecological conservation are concentrated along lakes, the coast, and hilly areas of southern Jiangsu. The multifunctional development of villages and towns is affected by endogenous and exogenous factors, including economic geographic location, natural resources, economic foundation, human capital, traffic conditions, market demand, infrastructure, and environmental governance. Natural factors have a significant impact on the supply of agricultural products and the formation of ecological conservation functions. The effects of socioeconomic factors on these four functions differ significantly. This study expands the theory of rural development functions, the classification and zoning paradigm, and the quantitative study of driving mechanisms. The results provide a reference for practical value and policy significance for the reconstruction of rural functions and rural revitalization. [ABSTRACT FROM AUTHOR]

Mercury (Hg) has always been a research hot spot because of its high toxicity. This study conducted in farmland near rare earth mining area and traffic facilities, which considered multiple pollution sources innovatively. It not only analyzed Hg spatial characteristics using inverse distance weighting and self-organizing map (SOM), but also assessed its pollution risk by potential ecological risk index (Er) as well as geoaccumulation index (Igeo), and identified the pollution sources with positive matrix factorization. The results showed that there was no heavy Hg pollution in most farmland, while a few sampling sites with Hg pollution were close to highway, railway station and petrol station in Xinfeng or in the farmland of Anyuan, which were divided into the cluster with highest Hg concentration in SOM. The vehicle exhaust emission and pesticide as well as fertilizer additions significantly contributed to the local Hg pollution. Besides, there was moderate pollution and high ecological risk in Anyuan assessed by Igeo and Er, respectively. In contrast, Xinfeng had the moderate and considerable ecological risks in a larger scale. The enriched Hg might harmed not only the nearby ecological environment, but also the human health when it entered human body through food chain. The three factors that contributed to mercury concentration in this area according to positive matrix factorization were natural source, traffic source and agricultural source, respectively. This study about Hg pollution in the typical area would provide scientific evidence for the particular treatment of Hg pollution from various pollution sources like traffic source, agricultural source, etc. [ABSTRACT FROM AUTHOR]

Freshwater resources are becoming increasingly scarce in coastal areas, limiting crop productivity in coastal farmlands. Although the characteristic of crop water use is an important factor for water conservation in coastal farmlands, it has not been studied extensively. This study aimed to depict the water use process of soil–plant systems under saline stress in coastal ecosystems and optimize water management. An intensive observation experiment was performed within China's Yellow River Delta to identify the water use processes and crop coefficients (KC) and also quantify the impacts of salt stress on crop water use. The results show that shallow groundwater did not contribute to soil water in the whole rotation; KC values for wheat–maize, wheat–sorghum, and wheat–soybean rotation systems were 45.0, 58.4, and 57% less, respectively, than the FAO values. The water use efficiency of the maize (8.70) and sorghum (9.00) in coastal farmlands was higher than that of the soybean (4.37). By identifying the critical periods of water and salt stress, this paper provides suggestions for water-saving and salinity control in coastal farmlands. Our findings can inform the sustainable development of coastal farmlands and provide new insights to cope with aspects of the global food crisis. [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]

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]

Farmers are one of the major uncertainty factors in remediation of contamination farmland. Based on the face-to-face questionnaire survey data of 553 farmers in 4 heavy metal-contaminated agricultural soil remediation projects in China, this study used methods, such as structural equation modeling and random forest to explore farmers' willingness to remediate, technology preference, and their key influencing factors for the first time. The results showed that farmers were willing to remediate contaminated soil and preferred phytoremediation, with 82.8% choosing phytoremediation, 12.5% choosing passivation, and 4.7% believing that the soil did not need to be remediated. In terms of willingness to remediate, the perceived benefits from participation in current remediation projects directly contributed to future willingness, with participation status (total impact coefficient 0.86) and perceived benefits (impact coefficient 0.49) being the main factors positively influencing farmers' willingness. With regard to technology preference, technical characteristics (soil quality, 17.1%; secondary contamination, 16.8%; and remediation period, 11.5%) were the main influencing factors. The sustainability of passivation effect and the possible secondary contamination restrict the promotion of passivation, whereas the cessation of agricultural production during the long remediation period restricts the promotion of phytoremediation. It is recommended to increase farmers' willingness to remediate by improving their perceived benefits and continuously overcoming the technical barriers by: (i) developing efficient and green passivators; and (ii) improving the efficiency of phytoremediation as well as intercropping or rotating cash crops while remediating. The results have important reference value for soil remediation in agricultural countries with small arable land per capita. [ABSTRACT FROM AUTHOR]

The spatial distribution, pollution level, and exposure risk of Pb in the finer dust (particle size < 63 μm) of residential areas in Xi'an, northwest China were investigated in this study. Geographical information systems and geodetector methods were used to analyze the spatial variability of Pb content in the finer dust of Xi'an and its forming mechanism. The enrichment factor was used to assess the extent of Pb pollution, and the hazard index was used to evaluate the health risks to children and adults exposed to Pb. The results showed that the average content of Pb in the finer dust of residential areas in Xi'an was 99.9 mg kg−1. In the Xi'an urban area, a higher Pb content was mainly found in the finer dust near the Second Ring Road of Xi'an City, and the Pb content in the old town of Xi'an City was relatively lower than that near the Second Ring Road. The results of geodetector analysis indicate that the spatial variability of Pb in the finer dust of the Xi'an urban area was primarily controlled by the interaction among vehicle emissions, daily behavior of residents, and industrial emissions. Pb in the finer dust from residential areas in all districts showed moderate enrichment. The non-cancer risks of Pb in the finer dust were within the safe range for both children and adults. However, the prolonged exposure risk of Pb in the finer dust of residential areas should be considered for children. [ABSTRACT FROM AUTHOR]

Identifying sources of soil and sediment PAHs and apportioning their contributions are key in building effective pollution abatement strategies, especially for Poyang Lake—the largest freshwater lake in China. PAHs were detected in all the monitored soil and sediment samples under three land use types, with the concentrations varying by area, ranging from moderate to relatively high. The order of PAHs content in different the land use types was as follows: industrial soil > grassland soil > agricultural soil. Although agricultural soil was dominated by LMW PAHs, industrial grassland soils were dominated by HMW PAHs. Based on factor analysis, non-negative matrix factorization analysis was effective in non-negative constrained skew rotation, especially for clear and interpretable source analysis of PAHs. [ABSTRACT FROM AUTHOR]

The Beijing–Tianjin–Hebei (BTH) region in China is a rapid development area with a dense population and high-pollution, high-energy-consumption industries. Despite the general idea that the coking industry contributes greatly to the total emission of potentially harmful elements (PHEs) in BTH, quantitative analysis on the PHE pollution caused by coking is rare. This study collected the pollutant discharge data of coking enterprises and assessed the risks of coking plants in BTH using the soil accumulation model and ecological risk index. The average contribution rate of coking emissions to the total emissions of PHEs in BTH was ~7.73%. Cross table analysis indicated that there was a close relationship between PHEs discharged by coking plants and PHEs in soil. The accumulation of PHEs in soil and their associated risks were calculated, indicating that nearly 70% of the coking plants posed a significant ecological risk. Mercury, arsenic, and cadmium were the main PHEs leading to ecological risks. Scenario analysis indicated that the percentage of coking plants with high ecological risk might rise from 8.50% to 20.00% as time progresses. Therefore, the control of PHEs discharged from coking plants in BTH should be strengthened. Furthermore, regionalized strategies should be applied to different areas due to the spatial heterogeneity of risk levels. [ABSTRACT FROM AUTHOR]

The Qinghai–Tibet Plateau is one of the most fragile and susceptible areas to climate change and human disturbances in the world. Here, a total of 48 soil samples were obtained from areas of different land uses within a typical basin in eastern Qinghai–Tibet, China. The selected potentially toxic elements (PTEs, including Cd, Cr, Cu, Pb, and Zn) contents were analyzed to explore their spatial patterns, ecological risks, and then the effects of land use types on these elements were assessed by self-organizing map (SOM) and random forest regression (RFR) models, and the main sources were revealed using positive matrix factorization (PMF) model. Results showed that mean concentrations of selected PTEs in surface soils were higher than local background values and those of subsurface soils. The low-degree ecological risk was obtained with comparatively high risks in the north and south of the study area. The results of the SOM and RFR models revealed that land use types affected the redistribution of PTEs in surface soil. The PMF model demonstrated that these PTEs were mainly derived from natural sources (46.7%), traffic emissions (31.2%), and industrial and agricultural inputs (22.1%). Natural sources were the essential contributors for these soil PTEs, especially for Cr. In addition to natural sources, traffic sources made great contributions for Cd, Pb, and Zn elements, while the enrichment of Cu was mainly related to industrial and agricultural activities. [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]

Biochar combined with fertilizer as a soil amendment benefits to improving soil fertility, especially soil organic carbon and crop yield. However, the effect of biochar on the improvement of soil properties and crop yield was varied from soil properties and limited for medium–low‐yield farmland in the North China. During the completely randomized field experiment, SIX treatments (biochar applied as 0, 15 and 30 t·ha‐1, under 240 and 300 kg N ha‐1 nitrogen fertilizer) were applied in wheat season and examined to reveal changes in the SOC and other properties of 0‐ to 10‐cm and 10‐ to 20‐cm soil layers. The results showed that two years after the application of biochar, a significant increase in the SOC was observed, ranging from 19.52% to 97.50% (p < 0.05) in the 0‐ to 20‐cm soil layer. Wheat yield and SOC content increased with increasing amount of biochar applied under the same amount of nitrogen fertilizer. The content of soil available potassium increased significantly under 30 t·ha‐1 biochar application (p < 0.05). Both biochar and nitrogen fertilizer application could increase wheat yield, and the effect of biochar application for increasing wheat yield was better than that of nitrogen fertilizer. Wheat yield and SOC content increased with increasing nitrogen fertilizer at the same amount of biochar application. The principal component analysis results showed that biochar input, SOC, available potassium and total nitrogen were the key factors affecting wheat yield. Biochar application is a fast and effective measure to improve SOC and wheat yield in medium‐ and low‐yield farmlands. [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]

A number of remediation measures have been used in paddy fields to alleviate serious cadmium (Cd) contamination, which may pose a public health risk through the food chain. In this study, a field trial was conducted in paddy fields with slight–moderate Cd contamination to investigate the remediation effects of combined remediation measures (CRMs), including the use of Cd-safe rice (Oryza sativa L.) cultivars, water management modes (WMMs), lime application (LA), soil amendment application (SAA), and foliar silicon (Si) fertilizers. Two groups of field trials were designed including CRMs with selenium (Se) and without selenium (non-Se) application. The results show that soil measures (LA + SAA) can increase the soil pH by 0.99 and decrease the soil DTPA-extracted Cd content by 34.19% (p < 0.05). All measures used in the present study significantly decreased the Cd content in husked rice and yield, except for the WMMs; the CRMs achieved the best results, and Se application enhanced the effects of all measures. This study shows that CRMs significantly decreased the Cd content in husked rice by 58.10%; this value increased to 72.69% after Se application (p < 0.05). These results provide useful information for selecting remediation measures in paddy fields with slight–moderate Cd contamination. [ABSTRACT FROM AUTHOR]

This report investigates the spraying of nano‐silica and fullerene on cucumber leaves to expose their ability to reduce the toxicity and uptake of metal(loid)s. Cucumber seedlings were randomly divided into six treatment groups: 10 mg/L nano‐SiO2, 20 mg/L nano‐SiO2, 10 mg/L Fullerene, 20 mg/L Fullerene, 5 mg/L Fullerene + 5 mg/L nano‐SiO2, and 10 mg/L Fullerene + 10 mg/L nano‐SiO2. Nano‐silica‐treated plants exhibited evidence of the potential mitigation of metal(loid)s poisoning. Specifically, results showed that 20 mg/L of nano‐silica promoted Cd uptake by plants; comparatively, 10 mg/L of nano‐silica did not significantly increase the silicon content in plants. Both low‐concentration combined treatment and low‐concentration fullerene groups inhibited metal(loid)s uptake by plants. Scanning electron microscopy (SEM) was then used to observe the surface morphology of cucumber leaves. Significant differences were observed on disease resistance in plants across the different nano‐material conditions. Collectively, these findings suggest that both nano‐silica materials and fullerene have the potential to control metal(loid)s toxicity in plants. [ABSTRACT FROM AUTHOR]

Deteriorating lake water quality has become a serious environmental issue around the globe. Heavy metals dissolved in the overlying water of lakes are notably more toxic than those found in lake sediment. Given this, we sought to better understand the characteristics of particular major ion and dissolved heavy metal in Dongting Lake—the second largest freshwater lake in China. Overlying water samples were collected from Dongting Lake to investigate the major ion geochemistry and to examine the relationship between the major ions and dissolved heavy metals. Chemical analysis of the overlying water showed that the average cation concentration was the highest for Ca2+, followed by Mg2+, Na+, and K+. Similarly, the highest anion concentration was SO42−, followed by Cl−, NO3−, and HCO3−. Total dissolved solids in the overlying water of Dongting Lake ranged from 66.19 to 159.20 mg/L, with an average value of 93.13 mg/L. The predominant hydrochemical type was Ca–SO4. The mean concentrations of dissolved heavy metal in both surface and deep waters decreased in the following order: Zn > Cr > Ni > Cu > Pb > Cd. Importantly, all of the selected heavy metals tested in the overlying water were lower than the corresponding toxicity reference values. Co-occurrence network analyses were performed and compared the correlations between all measured major ions and heavy metals. Results of the subsequent principal component analyses revealed that heavy metal levels in the aquatic environment primarily originated from natural processes and were enhanced by anthropogenic activities. [ABSTRACT FROM AUTHOR]

Modern farming practice features extensive overuse of additives in animal feed. Subsequent use of manure as a fertilizer has resulted in significant heavy metal accumulation in agricultural soil, which is particularly apparent in areas of intensive farming. Here, samples of dairy feed, manure, water, and soil were collected from four intensive dairy farms in China and analyzed to assess selected heavy metal concentrations (Cu, Zn, Cr, Ni, Pb, and Cd). Results revealed that all feed samples contained the selected heavy metals, attesting to the wide use of additives during intensive dairy farming. The average Cr and Pb concentrations were 6.1 to 17.1 times greater than their recommended guidelines. Overall, average heavy metal concentrations in manure decreased in the following order: Zn > Cu > Cr > Ni > Pb > Cd. Using data obtained from the sequential extraction procedure, proposed by the Community Bureau of Reference (BCR), metal bioavailability also decreased according to the following order: Pb (69.4%) > Cr (63.7%) > Ni (60.8%) > Cu (53.4%) > Zn (50.0%) > Cd (34.5%). Heavy metal levels in sampled wastewater were also relatively high; however, surface and well water levels were relatively low. Although use of manure in dairy farming has not resulted in serious pollution until now, Zn, Cu, and Cd are all known to pose significant risk to soil quality. Finally, principal component analysis (PCA) results indicated that heavy metal levels in soil originated predominantly from parent soil materials and were then enhanced by anthropogenic sources. [ABSTRACT FROM AUTHOR]

Particulate pollution, especially PM2.5 (particles with an aerodynamic equivalent diameter of 2.5 μm or less), has received increased attention in China recently. In this study, PM2.5 samples were collected in August 2013 and April 2014 from different regions of Baotou, the largest rare earth elements (REEs) processing city in northern China. The concentrations and distribution patterns of REEs in PM2.5 were analyzed, and the inhalation exposure to REEs associated with PM2.5 was assessed. The results showed that the REEs levels were 56.9 and 15.3 ng m−3 in August 2013 and April 2014, respectively. These values are much higher than those in non-REEs mining areas. The distribution patterns of REEs exhibited LREE enrichment. The Eu and Ce anomalies displayed slightly positive and negative values, respectively, which were in accordance with the background soil and ore. The average daily intake amounts of REEs for population through inhalation exposure of PM2.5 in Baotou were in the range of 5.09 × 10−7 to 2.25 × 10−5 mg kg−1 day−1. [ABSTRACT FROM AUTHOR]

ABSTRACT: The aim of this study is to evaluate the local impact of human activities on surface pollen assemblages and identify pollen indicators associated with grazing and cultivation in the Qinghai‐Tibetan Plateau. We analyzed 80 surface and 10 dung pollen samples from five communities of vegetation in the Qinghai Lake Basin. Each vegetation zone was identifiable based on surface pollen assemblages. Principal component analysis of 33 pollen taxa and two supplementary variables of human influences was used to assess the impact of anthropogenic activities on surface pollen assemblages in the Qinghai Lake Basin. Surface pollen assemblages were moderately influenced by cultivation, as indicated by the content of the cultivation‐associated Hordeum‐type and Brassiaceae pollen. Severe grazing led to changes in pollen assemblages, including increases in Chenopodiaceae, Plantago, Potentilla‐type, Thymelaeaceae and Aster‐type pollen. Pollen assemblages are similar among dung samples and are dominated by Artemisia, Poaceae, Fabaceae and Asteraceae. Hordeum‐type pollen content is relatively higher in dung samples, indicating herbivores are important in the dispersion of Cerealia Poaceae pollen into pastures. Characterizing modern pollen assemblages will provide a more precise reference for reconstructing prehistoric human activities during the Holocene based on fossil pollen assemblages in the Qinghai Lake Basin. [ABSTRACT FROM AUTHOR]

The lack of management in small-scale mining operations has the potential for negative repercussions, e.g., mine collapses, compared with well-regulated large-scale mines. Here, we used an in vitro model to investigate heavy metal soil pollution characteristics and their attendant health risks in an abandoned, small-scale lead (Pb) and zinc (Zn) mine located in southwestern China that had suffered from collapse. Our results showed the following: (1) Even the mine had been closed for many years, the soil was still heavily polluted by Pb, cadmium (Cd), and Zn, and there is a risk of secondary pollution. Pb, Zn, and Cd concentrations in the mining areas were all approximately 22-42 times higher than the background soil levels of Guangxi Province. (2) Cd had the largest bioaccessibility, and mining areas tend to have soils containing more bioaccessible metals (78 ± 14%, 27 ± 4%, and 38 ± 12% for Cd, Pb, and Zn in gastric phase and 40 ± 12%, 10 ± 5%, and 19 ± 8% in intestinal phase correspondingly). (3) Results of a stepwise, multiple regression analysis revealed that the total soil content of the three metals (Pb, Zn, and Cd), TOC (total organic carbon), soil composition, and Mn content were the main impact factors for the Pb, Cd, and Zn soil bioaccessibility in study area (R2 = 0.37~0.93). (4) A health risk assessment based on Pb, Cd, and Zn bioaccessibility indicated that the health risk for people in mine area is not high (HI is 1.07 at most and CR 2.40E−6 at most for children). [ABSTRACT FROM AUTHOR]

Since the construction of the Three Gorges Dam, the Poyang Lake hydrological characteristics obviously changed. During the impoundment period of the Three Gorges Reservoir, the hydrodynamic factors of Poyang Lake varied. Water level dropped, the velocity decreased and water exchange time lengthened, which changed the release of phosphorous from sediments. In order to investigate how the hydrodynamic factors influence the release of phosphorous from sediments, we used a two-way annular flume device to simulate the release characteristics of phosphorous from sediments under variable water levels and velocities. We found that both water level rising and velocity increasing could enhance the disturbance intensity to sediments, which caused the increase of suspended solids (SS) concentration, total phosphorus (TP) concentration in the overlying water, and the ability that phosphorus released to overlying water from sediments enhanced as well: when overlying water velocity maintained 0.3 m/s, SS concentration increased to 4035.85 mg/L at the water level 25 cm which was about 25 times compared to the minimum value and TP concentration in the overlying water also reached the maximum value at the water level 25 cm which was 1.2 times that of the value at 10 cm; when water level maintained 15 cm, SS concentration increased to 4363.35 mg/L at the velocity of 0.5 m/s which was about 28 times compared to the value of 0 m/s, and TP concentration in the overlying water increased from 0.11 mg/L to 0.44 mg/L. When the water level maintained 15 cm, the phosphorous release rate reached the maximum value of 4.86 mg/(md) at 0.4 m/s. The concentration of total dissolved phosphorous (TDP) and soluble reactive phosphate (SRP) both in overlying water and sediment-water interface were negatively correlated with pH. Using the parabolic equation, the optimum water level at a velocity of 0.3 m/s was calculated to be 0.57 cm, and the optimum velocity at water level of 15 cm was found to be 0.2 m/s. [ABSTRACT FROM AUTHOR]

Internal phosphorus (P) loading is regarded as a major eutrophication factor and may prevent improvements in lake water quality. Two new in situ passive sampling techniques, high-resolution pore-water equilibrators (HR-Peeper) and zirconium oxide-based diffusive gradients in thin films (Zr-oxide DGT), were combined to measure dissolved reactive phosphorus (DRP) (C[sub Peeper]) and labile phosphorus (C[sub DGT]) at five sites in South Dongting and West Dongting Lakes. The vertical distribution of C[sub Peeper] and C[sub DGT] displayed similarity, which demonstrated that the buffering capacity of the labile P in sediments was similar at different depths. The diffusion flux of P from the sediments at the sediment-water interface ranged from 1.9 to 88 ng m[sup -2] day[sup -1], with an average value of 38 ng m[sup -2] day[sup -1]. The P flux at the entrances to the Yuan, Li and Zi Rivers was fairly large at all five sites. The sediments at the five sites released P into overlying water, indicating that the sediments are an important source of P for Dongting Lake. [ABSTRACT FROM AUTHOR]

The dissolved reactive phosphorous (DRP) in pore water releases into the water body through the sediment–water interface. The DRP concentrations in the water and sediment of Poyang Lake were determined by high-resolution pore diffusion balance (HR-Peeper) and Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) techniques. The range of the DRP concentrations in the pore water samples of different sampling sites was 30–360 ng/cm3. The diffusion fluxes of DRP in the sediment–water interface were calculated based on the DRP concentration gradients. The range of DRP flux in Poyang Lake was 4.78–40.5 ng m−2d−1with an average value of 14.7 ng m−2d−1. The results showed that the P diffusion flux was higher in the middle of the Poyang Lake than both upstream and downstream of the lake. [ABSTRACT FROM PUBLISHER]

Industrial activities have led to serious air pollution and the potentially toxic elements in atmospheric particles can cause various health problems to humans. In this study, inhalable particulate matter (PM) and fine particles (PM) were collected from four typical sites in Baotou, an industrial city in northern China. We investigated both the mass concentrations of particulate matter and the concentrations of heavy metals (Cr, Ni, Pb, Cd, Cu, Mn, Co, and Zn) in the collected samples. We assessed the public health risks associated with atmospheric heavy metal exposure. The results showed that the mass concentrations of PM and PM as well as these heavy metal concentrations varied notably influenced by the prevailing wind directions. Among the studied metals, Zn, Mn, Pb, and Cr were the main metal pollutants in both PM and PM. The results of the health assessment showed that the eight heavy metals studied pose significant non-carcinogenic risks and Cr, Cd, and Co pose lifetime lung cancer risks to local residents, especially to children. [ABSTRACT FROM AUTHOR]

The Bayan Obo Mine, the largest rare earth element (REE) deposit ever found in the world, has been mined for nearly 60 years for iron and rare earth elements. To assess the influences of mining activities on geochemical behavior of REEs in soils, 27 surface soil samples and three soil profile samples were collected from different directions in the vicinity of the mine area. The total concentrations of REEs in surface soils varied from 149.75 to 18,891.81 mg kg with an average value of 1906.12 mg kg, which was apparently higher than the average values in China (181 mg kg). The order of the average concentrations of individual REEs in surface soils was similar to that in Bayan Obo ores, which confirmed that the concentration and distribution of REEs in the soils was influenced by the mining activities. The concentrations of single REE in the soil profiles showed a similar trend with depth with an increase at 0-25 cm section, then decreased and remained relatively stable in the deep part. The normalized curves inclined to the right side, showing the conspicuous fractionation between the light and heavy REEs, which supported by the North American Shale Composite (NASC) and Post-Archean Australian Shale (PAAS) normalized concentration ratios calculated for selected elements (La/Yb, La/Sm, Gd/Yb). Slight positive Ce anomaly and negative Eu anomaly were also observed. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the concentration and spatial distribution patterns of 9 potentially toxic heavy metal elements (As, Cd, Co, Cr, Pb, Cu, Zn, Mn, and Ni) in road dust in the Bayan Obo Mining Region in Inner Mongolia, China. Contamination levels were evaluated using the geoaccumulation index and the enrichment factor. Human health risks for each heavy metal element were assessed using a human exposure model. Results showed that the dust contained significantly elevated heavy metal elements concentrations compared with the background soil. The spatial distribution pattern of all tested metals except for As coincided with the locations of industrial areas while the spatial distribution of As was associated with domestic sources. The contamination evaluation indicated that Cd, Pb, and Mn in road dust mainly originated from anthropogenic sources with a rating of 'heavily polluted' to 'extremely polluted,' whereas the remaining metals originated from both natural and anthropogenic sources with a level of 'moderately polluted'. The non-cancer health risk assessment showed that ingestion was the primary exposure route for all metals in the road dust and that Mn, Cr, Pb, and As were the main contributors to non-cancer risks in both children and adults. Higher HI values were calculated for children (HI=1.89), indicating that children will likely experience higher health risks compared with adults (HI=0.23). The cancer risk assessment showed that Cr was the main contributor, with cancer risks which were 2-3 orders of magnitude higher than those for other metals. Taken in concert, the non-cancer risks posed by all studied heavy metal elements and the cancer risks posed by As, Co, Cr, Cd, and Ni to both children and adults in Bayan Obo Mining Region fell within the acceptable range. [ABSTRACT FROM AUTHOR]

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]

Poyang Lake is the largest freshwater lake in China and is one of the two largest lakes connected with the Yangtze River. It is an overflow lake which absorbs and releases water seasonally. To evaluate the geochemical cycling of nitrogen (N) in Poyang Lake, the spatial distributions of ammonia nitrogen (NH-N), nitrate nitrogen (NO-N) and total nitrogen (TN) in sediments and overlying water were measured. The experimental results showed that the average concentrations of TN in the sediment samples, surface water, and bottom water samples from Poyang Lake were 1,107.375 mg kg, 1.998 and 2.237 mg L, respectively. The highest concentrations of TN were measured in the water and sediment obtained from the river tail region south of Poyang Lake, with decreasing pattern from south to north affected by the river input. The contribution of TN to the internal load played an important role on N distribution in the overlying water. The vertical distribution of TN in sediment cores of Poyang Lake showed a decreasing trend with depth. The NH-N content in sediment cores initially decreased with depth and then increased slowly. The NO-N content in sediment cores exhibited an inverse trend compared with that of NH-N due to the influence of nitrification and denitrification processes. Release kinetic experiments of NH-N demonstrated that the maximum NH-N release rate occurred within first 5 min and reached 90-94 % of the maximum value within 0-10 min. [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]

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]

Eutrophication of lakes and reservoirs has become a worldwide environmental problem, and nitrogen (N) has been recognized as one of the key factors responsible for eutrophication. Nitrogen adsorbed on sediments may be released via chemical and biological processes under changing environmental conditions. Spatial distributions of concentrations of ammonia nitrogen (NH-N), nitrate nitrogen (NO-N) and total nitrogen (TN) were investigated in sediments and overlying water of Dongting Lake, the second largest freshwater lake in China. The concentration of TN in the sediments exhibited strong spatial variation with relatively high values in the eastern part and relatively low values in the southern part of the lake. The TN concentration in the water of different regions of Dongting Lake was affected by the internal load of sediment N. The vertical distribution of TN in sediment cores showed a decreasing trend with an increase in depth. Concentrations of NH-N in the sediment cores decreased with the depth increase until 6-8 cm and then increased slowly. However, concentrations of NO-N in the sediment cores showed an opposite trend from those of NH-N. A kinetic release experiment of NH-N showed that the maximum release rate occurred in the first 5 min and the amount of NH-N release reached 77.93-86.34 % of the total amount in 0-10 min. The release of NH-N in the surface sediments of Dongting Lake fits a first-order kinetics function. [ABSTRACT FROM AUTHOR]

China has relatively abundant rare earth elements (REEs) reserves and will continue to be one of the major producers of REEs for the world market in the foreseeable future. However, due to the large scale of mining and refining activities, large amounts of REEs have been released to the surrounding environment and caused harmful effects on local residents. This paper summarizes the data about the contents and translocation of REEs in soils, waters, atmosphere, and plants in REE mining areas of China and discusses the characteristics of their forms, distribution, fractionation, and influencing factors. Obviously high concentrations of REEs with active and bioavailable forms are observed in all environmental media. The mobility and bioavailability of REEs are enhanced. The distribution patterns of REEs in soils and water bodies are all in line with their parent rocks. Significant fractionation phenomenon among individual members of REEs was found in soil-plant systems. However, limited knowledge was available for REEs in atmosphere. More studies focusing on the behavior of REEs in ambient air of REE mining areas in China are highly suggested. In addition, systematic study on the translocation and circulation of REEs in various media in REEs mining areas and their health risk assessment should be carried out. Standard analytical methods of REEs in environments need to be established, and more specific guideline values of REEs in foods should also be developed. [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]

Surface runoff accounts for much of the phosphorus (P) input to and accelerated eutrophication of the fresh waters. The environmental fate of P receives increasing attention but the key mechanisms of P transport with surface runoff remain unclear. Through artificial rainfall experiments, characteristics of P loss with surface runoff during simulated rainfall are investigated under the conditions of various slope gradient and rainfall intensity and the factors of influencing are also discussed. Results show that the amount of runoff and sediment increased rapidly in a shorter time after runoff producing, then gradually turned to be stable. It shows significant correlation between the runoff volume and sediment. The amount of runoff and sediment increased with the increasing of slope gradient and rainfall intensity. P content in the runoff was higher in the early stage after runoff producing, and then stabilized gradually. Most of the P transformed through the sediment loss. [ABSTRACT FROM AUTHOR]

The phosphorus index (PI) can be used to effectively identify areas with high risks of phosphorus losses. Manures and fertilizers are important source factors for the establishment of the PI system. An artificial precipitation experiment was performed to evaluate phosphorus losses with the applications of different types of fertilizers and manures. The results showed that the total phosphorus (TP) losses in runoff followed the order of ammonium phosphate monobasic (NHHPO), ammonium hydrogen phosphate ((NH)HPO), monobasic potassium phosphate (KHPO), chicken manure, and cattle manure with surface application of these fertilizers and manures. The order was slightly changed to NHHPO, KHPO, (NH)HPO, chicken manure, and cattle manure with incorporation application under the same rainfall condition. Both the methods and the rate of manure application can affect the amounts of phosphorus in water and particles of runoff. More than 90 % of TP in runoff were lost through suspended particles. Manure application had a significant contribution to the P load in runoff. [ABSTRACT FROM AUTHOR]

The effects of antecedent soil moisture on losses of rare earth elements (REEs) and phosphorus (P) in runoff were evaluated through a simulated rainfall experiment at the rate of 83 mm h. The results revealed that antecedent moisture was a significant factor affecting the amounts of REE and P losses. It was observed that most REEs and P transported with sediments in the runoff. There was a significant correlation between the total amounts of REE losses and those of P losses in the runoff. The optimal antecedent moisture for minimization of losses for REEs ranged from 10.19 to 11.17% and it was 10.91% for P. [ABSTRACT FROM AUTHOR]

To adsorb hexavalent chromium (Cr(VI)) in polluted water, this paper prepared a UiO-66 (Zr6O4(OH)4(BDC)12) modified granular corncob composite adsorbent by hydrothermal method with in situ loading of UiO-66 on pretreated corncob particles. The physicochemical properties of the synthesized samples were characterized. Batch adsorption experiments were conducted to investigate the adsorption process of aqueous Cr(VI) under various conditions (different ionic strength, pH and co-existing anions). The results showed that UiO-66 was successfully loaded on the modified corncob particles. The isothermal adsorption data of Cr(VI) adsorption by the UiO-66 modified corncob fit well with the Langmuir model with the maximum adsorption capacity of Cr(VI) on UiO-66@Corn+ being 90.04 mg/g. UiO-66 loading could increase Cr(VI) adsorption capacity of Corn+. The kinetic study showed that the equilibrium time for Cr(VI) adsorption on UiO-66 modified corncob was about 180 min and the kinetic data followed the pseudo-secondary kinetic model. The Cr(VI) adsorption capacity on UiO-66@Corn+ decreased with the increasing solution pH, and the optimum pH range was 4–6. The ionic strength has little effect on the Cr(VI) adsorption capacity, but the coexistence of CO32−, SO42− and PO43− in the solution could significantly decrease the equilibrium adsorption capacity of Cr(VI). The adsorption mechanism analysis showed that Cr(VI) was adsorbed on the surface of adsorbents through electrostatic attraction and was reduced further to the less toxic Cr(III) by the electron donor on the surface of adsorbent. The electrostatic interaction was the main force affecting the adsorption of Cr(VI) by UiO-66. UiO-66@Corn+ had an excellent removal efficiency of Cr(VI) and excellent reusability. UiO-66@Corn+ could effectively remove Cr(VI) from water and have a promising application. [ABSTRACT FROM AUTHOR]

Based on systematic sampling of soil around the coal-fired power plant (CFPP), the content of Hg was determined, using atomic fluorescence spectrometry. The result shows that the content of Hg in soil is different horizontally and vertically, ranges from 0.137 to 2.105 mg/kg (the average value is 0.606 mg/kg) and is more than the average content of Hg in Shaanxi, Chinese and world soil. In this study, spatial distribution and hazard assessment of mercury in soils around a CFPP were investigated using statistics, geostatistics and geographic information system (GIS) techniques. Ordinary kriging was carried out to map the spatial patterns of mercury and disjunctive kriging was used to quantify the probability of the Hg concentration higher than the threshold. The maps show that the spatial variability of the Hg concentration in soils was apparent. These results of this study could provide valuable information for risk assessment of environmental Hg pollution and decision support. [ABSTRACT FROM AUTHOR]