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Vanadium (V) is ubiquitously distributed in environmental media, imposing toxic hazards to organisms in biogeosphere. This review focuses on a comprehensive summary of the ecological and human health risks ascribed to V pollution, based on existing V toxicity relevant publications. Lower doses of V (< 2 mg/L) is beneficial to plant growth, however, V reduces plant biomass, induces toxic effects on plant morphology and adversely affects the absorption of essential plant elements at higher levels (≥ 2 mg/L). Oxidative stress induced by reactive oxygen species (ROS) produced under V stress may be the main reason for V toxicity to terrestrial and aquatic organisms. Although V contributes to high-efficient biological nitrogen fixation as a co-factor, V alters microbial community structures and drives its evolution. V can also accumulate in and harm human bodies. Knowledge gaps and further perspectives in aspects of V risks are thereby proposed, such as more toxic data reports for deriving V environmental quality criteria, elucidating the molecular mechanisms of detoxification and tolerance of organisms to V for bioremediation applications, and exploring the medical potential of V with the prevention of V toxicity to humans. This review advances our understanding of the toxic effects of V in the ecosystem and inspires future efforts on V management as well as application. [ABSTRACT FROM AUTHOR]

Purpose: From perspective of risk management and control, the ecological risk contributed from various sources can give direct risk information in selecting priority pollutants to control in river ecosystem restoration. However, studies combined receptor model with risk assessment to obtain ecological risk in every source category that is still limited. It is essential to quantitatively and spatially analyse the contributions of various sources to both the content and ecological risk in river system. Materials and methods: Ten trace metals in 47 sediment samples were collected in Le'an River, which is the main tributary of the largest freshwater lake in China, Poyang Lake and analysed by laboratory analysis. The potential ecological risk index (PERI) model was used to evaluate the ecological risk posed by sediment trace metals. The positive matrix factorization (PMF) was utilized to identify the source of sediment trace metal and apportion their contribution. The ecosystem risks of the sources were quantitatively analysed by combining PERI and PMF, termed PMF-PERI. In addition, we conducted a spatial dissimilarity analysis of the source contribution distributions. Results and discussion: The ecological risk assessment results showed that the metals Cd, Cu, and Hg may cause the main ecological hazards. Source apportionment of the trace metal concentrations indicated that the dominant source of trace metals in the sediment was human activities (55.83%), such as Pb-Zn mining and agricultural activities (30.33%), gold smelting (13.62%) and copper mining (11.89%). Source apportionment of the ecological risks posed by the trace metals indicated that natural sources were the main ecosystem risk sources (64.75%), followed by Pb-Zn mining and agricultural activities (14.65%), copper mining (10.67%) and gold smelting (9.93%). The results of spatial dissimilarity analysis indicated that the significant spatial variation in the contribution compositions was related to the locations of the sources and the river. Conclusions: The results of this study indicated that the emission reduction of agricultural activities should be given priority attention for protecting the watershed environment of the Le'an River. In addition, this study extends the use of risk assessment in receptor model source apportionment. [ABSTRACT FROM AUTHOR]

We explored the effect of the presence or absence of humic acid (HA) on the sorption behaviour of Sr onto soil. We examined three different experimental cases for Sr sorption: (1) sorption in the presence of only colloidal HA, (2) sorption in the presence of only soil and (3) sorption in the presence of both colloidal HA and soil (HS). A batch technique was used to study the influencing factors, including the amount of colloidal HA, solid content, pH, initial concentration of Sr and contact time. The experiments showed that the influencing factors significantly affected the sorption process. For example, in the case of soil and HS, the sorption percentage increased rapidly with increasing solid content at m/V < 20 g/L, changing from 8.35% and 37.54% to 49.09% and 77.03%, respectively. Moreover, scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterize samples. The kinetics and isotherms of Sr were best described by the pseudo-second-order and Langmuir models, which indicated that the process was controlled by chemisorption and uniform monolayer sorption with constant energy on the outer surface. These findings provide valuable information for predicting strontium migration in radioactive waste disposal sites. [ABSTRACT FROM AUTHOR]

Palygorskite (PAL) was modified with sodium dodecyl sulfate (SDS) for the removal of Sr(II) from aqueous solutions. Analysis of the structural characteristics of PAL before and after modification showed that PAL was successfully modified with SDS. Sorption experiments were conducted in batch mode under optimum conditions to evaluate the effect of initial pH and co-existing ions on the removal of Sr(II) by SDS-modified PAL. The equilibrium sorption isotherm data for Sr(II) were analyzed using Freundlich and Langmuir isotherm sorption equations, and the data fitted well to the Freundlich isotherm model. Pseudo-first-order and pseudo-second-order kinetic models were examined, and the sorption of Sr(II) showed better agreement with the pseudo-second-order kinetic model (r2 > 0.99). The desorption experiments indicated that the SDS-modified PAL having sorbed Sr(II) does not release significant amounts of Sr(II) into the environment under natural conditions, thus avoiding secondary pollution. [ABSTRACT FROM AUTHOR]

The issue of contaminated sites has been highlighted as an immediate priority in the 13th Five-Year Plan of China. Identification and prioritization of contaminated sites are of key importance for proposing effective strategies for the regional management of contaminated sites. In this study, three advanced multi-attribute methodologies, the risk-based priority methodology, the regional risk assessment methodology, and the dominance-based rough set approach (DRSA), were comparatively employed to screen contaminated sites in, Guangxi, Southwest of China. The results of the three prioritizations show that the highest ranking site identified by the three methods had great agreement. In regard to the screening attributers, while the risk-based prioritization methodology and regional risk assessment methodology allowed a high discrimination in the screening of contaminated sites associated with different attributes, such as farmland, residential areas, contaminant level, number of people, area, storage quality, site service life, and surrounding communities, the DRSA allowed the identification of contamination strength (CS) and contamination potential (CP). [ABSTRACT FROM AUTHOR]

A host of environmental consequences will result from global warming, but arguably, the effect on water resources is one of the most consequential. This paper synthesizes results of published modeling studies that examined the groundwater system and hydrologic cycle under the Representative Concentration Pathway (RCP) 8.5 scenario (CO2 at 936-ppm level at year 2100). Natural replenishment of groundwater occurs predominantly from infiltration of precipitation and surface impoundments. Therefore, the first stage of the study was to review a changed hydrologic cycle under RCP 8.5 in terms of influence from (1) precipitation, evapotranspiration, and soil moisture; (2) surface water and its interaction with groundwater; (3) extreme hydrologic events, and (4) teleconnection patterns. The general pattern of climate impact on groundwater resources follows the precipitation pattern with depletion in tropical and/or subtropical regions and with increase in the high-latitude regions of the Northern and Southern Hemispheres. However, regional variability also corresponds to the heterogenous impact of climate changes on regional distribution of precipitation and evapotranspiration, localized interaction between surface water and groundwater, and distances from the oceans with rising sea level. The decline of the water table in many areas may seriously reduce irrigated crop production and adversely impact groundwater-dependent ecosystems. Relatively fewer studies have been conducted on climate-change impacts on groundwater resources compared to surface-water systems, and the uncertainties on the recharge estimates are large. There appears to be an urgent need for including groundwater systems in climate impact assessment and in climate mitigation strategies. [ABSTRACT FROM AUTHOR]

To develop novel 99mTc labeled nitroimidazole imaging agents for imaging tumor hypoxia, 99mTc labeled ethylene diamine tetraacetic acid derivative of 4-nitroimidazole was reported by us earlier, which showed disadvantage of an unsatisfactory tumor-to-blood ratio. Therefore, 2-nitroimidazole was adopted as a pharmacophore to synthesize EDTA-2-EtNHNM, which was radiolabeled with 99mTc in high yield to achieve 99mTc-EDTA-2-EtNHNM. 99mTc-EDTA-2-EtNHNM was hydrophilic and exhibited good in vitro stability. Cellular experiment demonstrated its hypoxic selectivity while biodistribution results showed improved tumor-to-blood and tumor-to-muscle ratios. SPECT imaging studies of 99mTc-EDTA-2-EtNHNM indicated obvious accumulation in tumor, suggesting its potential to be a radiotracer for imaging tumor hypoxia. [ABSTRACT FROM AUTHOR]

Investigation of surface water and groundwater interaction (SW-GW interaction) provides basic information for regional water-resource protection, management, and development. In this survey of a 10-km-wide area along both sides of the Songhua River, northeast China, the hydrogeochemical responses to different SW-GW interactions were studied. Three types of SW-GW interactions were identified—“recharge”, “discharge”, and “flow-through”—according to the hydraulic connection between the surface water and groundwater. The single factor index, principal component analysis, and hierarchical cluster analysis of the hydrogeochemistry and pollutant data illuminated the hydrogeochemical response to the various SW-GW interactions. Clear SW-GW interactions along the Songhua River were revealed: (1) upstream in the study area, groundwater usually discharges into the surface water, (2) groundwater is recharged by surface water downstream, and (3) discharge and flow-through coexist in between. Statistical analysis indicated that the degree of hydrogeochemical response in different types of hydraulic connection varied, being clear in recharge and flow-through modes, and less obvious in discharge mode. During the interaction process, dilution, adsorption, redox reactions, nitrification, denitrification, and biodegradation contributed to the pollutant concentration and affected hydrogeochemical response in the hyporheic zone. [ABSTRACT FROM AUTHOR]

The sorption of U(VI) on shale has been experimentally investigated as a function of pH, initial uranium concentration, rock particle size and water-rock ratio. The results showed the sorption equilibrium time was about 10 days, and the adsorption capacity presented a negative relationship with rock particle size and positive correlation with the liquid-solid ratio, also influenced by pH. The sorption process was fitted well with Freundlich isotherm. Experimental column was fully penetrated by tritium at about 230 min with a velocity of 0.13 cm/min while uranium was not penetrated the rock column in 180 days. [ABSTRACT FROM AUTHOR]

Nitrogenous pollutants from intense human activities have become serious environmental and health problems worldwide, particularly in groundwater source areas used for public water supply. To investigate the genesis and pollution risks associated with elevated concentrations of ammonium nitrogen in a groundwater source area, investigations were undertaken in the Jinji groundwater source area, located in an arid loess plain in northwestern China where 16 groundwater samples were collected from an aquifer used for water supply. The investigation indicated that high concentrations of ammonium nitrogen originated mainly from: infiltration of water from the Yellow River; livestock; and the discharge of industrial wastes. Measured parameters including pH, the permanganate index and the oxidation reduction potential could be used as important indicators of the genesis of ammonium nitrogen. A modified DRTCLN model was applied to the observed distribution of ammonium nitrogen to assess pollution risk of regional groundwater. The model was optimized by rebuilding the index system, and the analytic hierarchy process was used to calculate the rating scale of each index. A Monte Carlo simulation was performed to analyze the uncertainty of results of the risk assessment. The result showed that the risk value is relatively low in most areas of the groundwater source area. Only an industrial area in the southwestern part of the groundwater source area was classified as high risk; it should be the key factor of pollution control. [ABSTRACT FROM AUTHOR]

A novel ethylene diamine tetraacetic acid derivative of 4-nitroimidazole (EDTA-4-EtNHNM) was successfully synthesized as a carrier molecule and it was radiolabeled with Tc in high yield to obtain Tc-EDTA-4-EtNHNM, which was hydrophilic and had good in vitro stability. The tumor cell experiment and the biodistribution study in mice bearing S180 tumor showed that this complex exhibited a hypoxic selectivity and had high accumulation in tumor tissue with major clearance through urinary tract. High tumor uptake and tumor/muscle ratio of the complex suggests promise towards further evaluation. [ABSTRACT FROM AUTHOR]

Nitrate pollution has pervaded many parts of the world, especially in developing countries such as China. Based on the available groundwater nitrate data sets in China (2000-2015), the groundwater pollution levels at the provincial scale are evaluated which contains 33 provinces (units) except for Macau because of lacking data. Then, the potential risks posed to human health in national scale are quantified. In order to make the results more precise and systematical, both drinking and dermal contact exposure pathways are considered, and the influenced crowd are more finely divided into four groups to study the impacts of age and gender on the outcome, which include infants (0-6 months), children (7 months-17 years old), adult males (18 years old-), and adult females (18 years old-). Results indicate that there are seven units whose groundwater nitrate concentrations exceed the standard value with Shaanxi being a seriously poor condition. Facing the same level of nitrate, the health risk level changes in the order of infants > children > adult males > adult females. That is to say, minors and males are more vulnerable compared with adults and females, respectively. There is no adverse effect on adult females of the whole country, while gender really impacts on the health risk assessment result. Adult males, children, and infants face various degrees of health risk respectively in Shaanxi and Shandong, which are needed to pay more attention to. [ABSTRACT FROM AUTHOR]

Due to their toxicity and bioaccumulation, trace metals in soils can result in a wide range of toxic effects on animals, plants, microbes, and even humans. Recognizing the contamination characteristics of soil metals and especially apportioning their potential sources are the necessary preconditions for pollution prevention and control. Over the past decades, several receptor models have been developed for source apportionment. Among them, positive matrix factorization (PMF) has gained popularity and was recommended by the US Environmental Protection Agency as a general modeling tool. In this study, an extended chemometrics model, multivariate curve resolution-alternating least squares based on maximum likelihood principal component analysis (MCR-ALS/MLPCA), was proposed for source apportionment of soil metals and applied to identify the potential sources of trace metals in soils around Miyun Reservoir. Similar to PMF, the MCR-ALS/MLPCA model can incorporate measurement error information and non-negativity constraints in its calculation procedures. Model validation with synthetic dataset suggested that the MCR-ALS/MLPCA could extract acceptable recovered source profiles even considering relatively larger error levels. When applying to identify the sources of trace metals in soils around Miyun Reservoir, the MCR-ALS/MLPCA model obtained the highly similar profiles with PMF. On the other hand, the assessment results of contamination status showed that the soils around reservoir were polluted by trace metals in slightly moderate degree but potentially posed acceptable risks to the public. Mining activities, fertilizers and agrochemicals, and atmospheric deposition were identified as the potential anthropogenic sources with contributions of 24.8, 14.6, and 13.3 %, respectively. In order to protect the drinking water source of Beijing, special attention should be paid to the metal inputs to soils from mining and agricultural activities. [ABSTRACT FROM AUTHOR]

Underground injection (UI) is an effective and efficient means of disposing of wastewater from shale gas production. However, the influence of UI on groundwater systems should be examined carefully to protect drinking groundwater sources. A regional hydrogeological model based on TOUGH2-MP/EOS7R of part of the Sichuan Basin is established to simulate pressure changes and solute transport in response to wastewater injection into deep aquifers. Wastewater is assumed to be injected through a well at a rate of 5.45 kg s−1 for 5 years and a post-injection period of 45 years. The simulation results indicate that UI will cause significant pressure buildup during the injection period, after which pressure will dissipate during the post-injection period. The mass fraction of solute increased over the entire simulation period. The draft regulation under the Safe Drinking Water Act and the level III groundwater quality standards regulated by the Chinese government is referenced as the criteria for evaluating the influence of UI on groundwater systems. It is found that maximum pressure levels caused by UI may exceed safe levels. Uncertainties with respect to permeability are analyzed from previous studies and injection test results. Lower levels of permeability incur higher degrees of pressure buildup when UI is implemented. Different injection schemes are discussed, and we verify that pressure buildup from time-variant injection schemes is less than that from constant injection schemes for the same total injection volume. Injection schemes should be carefully evaluated before implementing UI in a shale gas reservoir. [ABSTRACT FROM AUTHOR]

Purpose: Taking into account great spatial heterogeneity in soil environments is essential to carrying out an accurate soil contamination assessment at the regional scale. Although there are numerous methods for distinguishing between natural and anthropogenic element contents, few studies focus on on-site determination methods, with few site-specific and sensitive references available. In this study, site background concentration is estimated as an on-site reference for soil contamination assessment. Materials and methods: Here, a support vector machine (SVM) is used to predict the site background concentration based on nine influential factors of soil formation. Three machine-learning algorithms, which are considered efficient in solving optimization problems, are used to select the optimal parameters of the SVM. These three algorithms are as follows: (1) a grid search algorithm, (2) a genetic algorithm, and (3) a particle swarm optimization algorithm. Results and discussion: Model performances were evaluated using squared correlation coefficients and root-mean-square error. Their subsequent application to soil contamination assessment demonstrated that indiscriminate use of a consistent reference across all soil types in an environmental site assessment may result in under- and over-estimation. These problems are likely to be resolved by using site background concentration predictions to establish contaminated versus un-contaminated regions. Conclusions: We conclude that a SVM based on factors of influence for soil formation is an effective method for site background concentration prediction and substantially improved the suitability of background references at our study site. Slight modifications would make this approach applicable to other regions and soil types. [ABSTRACT FROM AUTHOR]

Groundwater vulnerability assessment has become a useful tool to delineate areas for the prevention and control of groundwater pollution. The paper proposed the APLIE method by combining the DRASTIC, PI, COP, European approach with the characteristics of karst-phreatic aquifer in North China in the help of ARCGIS, which was used to assess the groundwater vulnerability of Dawu water source, Shandong Province, China. Water abundance (A), protective cover (P), types of land use (L), infiltration amount of precipitation (I) and groundwater exploitation (E) were picked up to compose the index system for characterizing the hydrogeology and environmental geology setting and evaluating the aquifer vulnerability. Weights of new index system were reassigned using the analytic hierarchy process method based on the relative importance of indexes. The assessment results indicated that groundwater vulnerability mapping with APLIE method is in better agreement with the current hydrogeological and environment geological understanding of Dawu water source area compared with the results obtained from PI and COP methods. And the exceeding standard subareas of ammonia nitrogen (NH-N) and electric conductivity in the study area proved the reliability of groundwater vulnerability results. Subareas of vulnerability were portioned by natural breaks based on the spatial platform of ARCGIS. The integrated vulnerability map showed that the very high and high vulnerability subareas were formed for reasons of highest or higher infiltration amount of precipitation (I), worst or worse protective cover (P), most complex type of land use (L), poor water abundance (A) and over groundwater exploitation (E). Sensitivity analyses showed that infiltration amount of precipitation (I) is the most sensitive factor affecting groundwater vulnerability in the case study. In short, APLIE method was applicable to assess the karst-phreatic vulnerability in the study area with readily available hydrogeological and environment geological data. Hence, the groundwater vulnerability mapping is a promising tool for sensible groundwater resource management and land use planning, which contributes to the development of human survival and sustainable development of groundwater. [ABSTRACT FROM AUTHOR]

The soil pollution by heavy metals was characterized in the mine tailings and surrounding soils of an old Pb-Zn mine in Huize County. Three hundred and ninety-six samples of agricultural and non-agricultural soil were analyzed for the total metal concentration by acid digestion and sixty-eight selected soil samples were used to determine the chemical fractionation of heavy metals with the modified BCR sequential extraction method. The pollution index of the heavy metals indices for As, Cd, Cr, Cu, Hg, Pb and Zn of non-agricultural soil and agricultural soils in the study area indicated the spreading of heavy metal pollution. Sequential extraction showed that most of Cd existed in an exchangeable form (31.2 %). The available content of Pb, Cu and Zn was mainly distributed in acid extractable fractions and Fe/Mn oxide fractions (27.9, 30 and 27.2 %), and Hg, As and Cr were mainly associated with residual fractions (90.4, 72.9 and 76.8 %). The risks of heavy metals were also evaluated by the risk assessment code (RAC) and potential ecological risk index, respectively. The results of RAC showed a medium and high risk of Cd (45.6 and 54.4 %), medium risk of Zn (100 %), low and medium risk of Cu (41.2 and 58.8 %), largely no risk of Hg (97.1 %), and mainly low risk of As and Pb (92.6 and 91.8 %). The range of the potential ecological risk of soil was 58.2-1839.3, revealing a considerably high ecological risk in the study area, most likely related to acid mine drainage and the mining complexes located in the area. The results can be used during the ecological risk screening stage, in conjunction with the total concentrations and metal fractionation values, to better estimate ecological risk. [ABSTRACT FROM AUTHOR]

The BCR sequential extraction procedure was compared with EDTA, HCl, and NaNO single extractions for evaluating vanadium bioavailability in alfalfa rhizosphere soil. The amounts of vanadium extracted by these methods were in the following order: BCR (bioavailable V) > EDTA ≈ HCl > NaNO. Both correlation analysis and stepwise regression were adopted to illustrate the extractable vanadium between different reagents. The correlation coefficients between extracted vanadium and the vanadium contents in alfalfa roots were R = 0.948, R = 0.902, R = 0.816, and R = 0.819. The stepwise multiple regression equation of the NaNO extraction was the most significant at a 95 % confidence interval. The influence of pH, total organic carbon, and cadmium content of soil to vanadium bioavailability were not definite. In summary, both the BCR sequential extraction and the single extraction methods were valid approaches for predicting vanadium bioavailability in alfalfa rhizosphere soil, especially the single extractions. [ABSTRACT FROM AUTHOR]

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In this study, continuous monitoring of PM was carried out for 1 year period at one of the largest residential areas in Beijing. Annual mean of PM during sampling period was 100.4 µg/m. The seasonal variation trend of PM was winter > spring > autumn and summer. The total mass concentrations of metals in PM ranged from 0.4 to 13.2 μg/m. There were significant ( p < 0.05) seasonal variations for concentrations of Ca, Al, Mn, As, Rb, Cr, Ni, Cd and Co, seasonal variations in PM-associated metals were not necessarily the same as the seasonal variation in PM, related to differing seasonal trends in source types. The impact of meteorological factors (e.g., wind speed) on metals levels of PM was found to be significant by regression models. The EFs value of Ag, Ca, Cd, Pb, Zn, As, Cu, and Cr were higher than ten, suggesting that those elements were primarily contributed by anthropogenic sources. Seasonal characteristic of EFs were found for As, Cr, Ca and Ag, which indicating the seasonal pollution sources types for those metals. Overall, these findings indicated that the pollution control of ambient PM should not be negligible in residential area in Beijing and the local government should pertinent and accurate prevent and control of air pollution as well as protect human health. [ABSTRACT FROM AUTHOR]

The aquifer in the Beijing Plain is intensively used as a primary source to meet the growing needs of the various sectors (drinking, agricultural, and industrial purposes). The analysis of groundwater chemical characteristics provides much important information useful in water resources management. To characterize the groundwater chemistry, reveal its spatial and seasonal variability, and determine its quality suitability for domestic and agricultural uses, a total of 200 groundwater samples were collected in June and October 2012 from 100 exploited wells in Daxing District, Beijing, China. All of the indices (39 items) listed in the Quality Standard for Groundwater of China (QSGC) as well as eight additional common parameters were tested and analyzed for all samples, based on which research target was achieved. The seasonal effect on the groundwater chemistry and quality was very slight, whereas the spatial changes were very obvious. The aquifer is mainly dominated by HCO-Ca·Mg-type water. Of the 39 quality indices listed in QSGC, 28 indices of all of the samples for the 2 months can be classified into the excellent level, whereas the remaining 11 indices can be classified into different levels with the total hardness, NO, NO, and Fe being the worst, mainly distributed in the residential and industrial land. According to the general quality index, the groundwater can be classified from good to a relatively poor level, mainly from southeast to northwest. Furthermore, the relatively poor-level area in the northwest expands to the southeast more than in the past years, to which people should pay attention because this reverse spatial distribution relative to the natural law indicates an obvious, anthropogenic impact on the groundwater. In addition, the groundwater in this area is generally very suitable for irrigation year-round. Nevertheless, we recommend performing agricultural water-saving measures for the sustainable development of water and urbanization, groundwater recovery, and ecological safety. [ABSTRACT FROM AUTHOR]

Due to the sea level rise and the excessive exploitation of freshwater, seawater intrusion is becoming a critical issue. To clarify the degree of seawater intrusion in Donghai Island and the microbial community structure and functional response to seawater intrusion, groundwater samples and sediment samples were collected at profiles A, B; the profiles were along the direction of groundwater flow, perpendicular to the coastline, a hydrogeochemical survey and soil microbial community analysis were also performed. The hydrogeochemistry analysis showed that the chemical type of groundwater was Na-Cl, brackish water was dominant in the area, and coastal groundwater was strongly affected by seawater intrusion. The effect of seawater intrusion on structural and functional diversity of soil microbes was analyzed from soil samples of the study area, by polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). The results of DGGE patterns and phylogenetic tree show that the extent of seawater intrusion has directly influenced soil microbial community structure. The changes of microbial community structure might be related to the major elements' concentrations in groundwater. Phylogenetic affiliation indicated that γ-proteobacteria were dominated in the profile A, while β-proteobacteria were mainly appeared in the profile B. The Flavobacteriaceae was only appeared at the shrimp ponds nearby. [ABSTRACT FROM AUTHOR]

In order to solve the collinear problem and improve the estimation accuracy of the chemical mass balance (CMB) model which can be essentially regarded as a constrained optimization process, in this study, a hybrid genetic pattern search algorithm (HGPS) was proposed and applied to apportion the source contributions for sediment polycyclic aromatic hydrocarbons (PAHs) in the Pearl River Delta (PRD) region, China. Simulation results with developed synthetic datasets indicated that the estimated source contributions by HGPS were more close to the true values than CMB8.2. Utilizing the HGPS-CMB, residential coal and traffic tunnel were apportioned as the major sources of sediment PAHs in the PRD region. For freshwater surface sediments, the average contribution from residential coal ranged from 32 to 55 %, and traffic tunnel ranged from 13 to 33 %, while the major sources for marine sediments were traffic tunnel (10 ~ 56 %). These results provide information for developing better PAH pollution control strategies for the PRD. [ABSTRACT FROM AUTHOR]

A physical, hydrochemical and isotopic evaluation of springs in Beijing was conducted in 2009 to reveal apparent changes in the properties of those springs. The results showed that most of the 2nd class springs and more than 50 % of the 1st class springs recorded in the early 1980s were depleted, while the discharges of existing springs have also decreased sharply. In addition, the majority of springs were of the HCO-Ca-Mg type and good water quality, with the quality indices changing slightly compared to those recorded 30 years ago. The abundances of H, O, and H in the springs indicated that most of the springs were of meteoric origin with a relatively close connection to modern atmospheric precipitation. As a result, the springs have a relatively strong renewability within a shallow circulation. [ABSTRACT FROM AUTHOR]

Characterizing water quality and identifying potential pollution sources could greatly improve our knowledge about human impacts on the river ecosystem. In this study, fuzzy comprehensive assessment (FCA), pollution index (PI), principal component analysis (PCA), and absolute principal component score-multiple linear regression (APCS-MLR) were combined to obtain a deeper understanding of temporal-spatial characterization and sources of water pollution with a case study of the Jinjiang River, China. Measurement data were obtained with 17 water quality variables from 20 sampling sites in the December 2010 (withered water period) and June 2011 (high flow period). FCA and PI were used to comprehensively estimate the water quality variables and compare temporal-spatial variations, respectively. Rotated PCA and receptor model (APCS-MLR) revealed potential pollution sources and their corresponding contributions. Application results showed that comprehensive application of various multivariate methods were effective for water quality assessment and management. In the withered water period, most sampling sites were assessed as low or moderate pollution with characteristics pollutants of permanganate index and total nitrogen (TN), whereas 90 % sites were classified as high pollution in the high flow period with higher TN and total phosphorus. Agricultural non-point sources, industrial wastewater discharge, and domestic sewage were identified as major pollution sources. Apportionment results revealed that most variables were complicatedly influenced by industrial wastewater discharge and agricultural activities in withered water period and primarily dominated by agricultural runoff in high flow period. [ABSTRACT FROM AUTHOR]

In order to investigate the distribution of the total petroleum hydrocarbons (TPH) in groundwater and soil, a total of 71 groundwater samples (26 unconfined groundwater samples, 37 confined groundwater samples, and 8 deeper confined groundwater samples) and 80 soil samples were collected in the Songyuan oilfield, Northeast China, and the vertical variation and spatial variability of TPH in groundwater and soil were assessed. For the groundwater from the unconfined aquifer, petroleum hydrocarbons were not detected in three samples, and for the other 23 samples, concentrations were in the range 0.01-1.74 mg/l. In the groundwater from the confined aquifer, petroleum hydrocarbons were not detected in two samples, and in the other 35 samples, the concentrations were 0.04-0.82 mg/l. The TPH concentration in unconfined aquifer may be influenced by polluted surface water and polluted soil; for confined aquifer, the injection wells leakage and left open hole wells may be mainly responsible for the pollution. For soils, the concentrations of TPH varied with sampling depth and were 0-15 cm (average concentration, 0.63 mg/g), >40-55 cm (average concentration, 0.36 mg/g), >100-115 cm (average concentration, 0.29 mg/g), and >500-515 cm (average concentration, 0.26 mg/g). The results showed that oil spillage and losses were possibly the main sources of TPH in soil. The consequences concluded here suggested that counter measures such as remediation and long-term monitoring should be commenced in the near future, and effective measures should be taken to assure that the oilfields area would not be a threat to human health. [ABSTRACT FROM AUTHOR]

An investigation was conducted in Beijing to identify the groundwater evolution and recharge in the quaternary aquifers. Water samples were collected from precipitation, rivers, wells, and springs for hydrochemical and isotopic measurements. The recharge and the origin of groundwater and its residence time were further studied. The groundwater in the upper aquifer is characterized by Ca-Mg-HCO type in the upstream area and Na-HCO type in the downstream area of the groundwater flow field. The groundwater in the lower aquifer is mainly characterized by Ca-Mg-HCO type in the upstream area and Ca-Na-Mg-HCO and Na-Ca-Mg-HCO type in the downstream area. The δ D and δO in precipitation are linearly correlated, which is similar to WMWL. The δ D and δO values of river, well and spring water are within the same ranges as those found in the alluvial fan zone, and lay slightly above or below LMWL. The δ D and δO values have a decreasing trend generally following the precipitation → surface water → shallow groundwater → spring water → deep groundwater direction. There is evidence of enrichment of heavy isotopes in groundwater due to evaporation. Tritium values of unconfined groundwater give evidence for ongoing recharge in modern times with mean residence times <50 a. It shows a clear renewal evolution along the groundwater flow paths and represents modern recharge locally from precipitation and surface water to the shallow aquifers (<150 m). In contrast, according to C ages in the confined aquifers and residence time of groundwater flow lines, the deep groundwater is approximately or older than 10 ka, and was recharged during a period when the climate was wetter and colder mainly from the piedmont surrounding the plain. The groundwater exploitation is considered to be 'mined unsustainably' because more water is withdrawn than it is replenished. [ABSTRACT FROM AUTHOR]

In this study, a method of positive matrix factorization (PMF) combined support vector machines (SVMs) was adopted to identify possible sources and apportion contributions for trace element pollution in surface sediments from the Jinjiang River, Southeastern China. Utilizing diagnostics tools, four significant factors were extracted from sediment samplers, which were collected in December 2010 at 15 different sites. By treating source identification as a pattern recognition problem, the factor loadings derived from PMF were classified by SVM classifiers which have been trained and validated with fingerprints of eight potential source categories. Using SVM, industrial wastewater from lead ore mining and metal handcraft manufacture, atmospheric deposition, and natural background were identified as main sources of trace element pollution in surface sediments from the Jinjiang River, which were affirmed by visually comparing compound patterns and the differences between the predicted and actual fractional compositions. Apportionment results showed that source of lead ore mining made the largest contribution (33.62 %), followed by atmospheric deposition (30.99 %), metal handcraft manufacture (30.09 %), and natural background (5.29 %). [ABSTRACT FROM AUTHOR]

The nonpoint source (NPS) pollution is difficult to manage and control due to its complicated generation and formation. Load estimation and source apportionment are an important and necessary process for efficient NPS control. Here, an integrated application of semi-distributed land use-based runoff process (SLURP) model, export coefficients model (ECM), and revise universal soil loss equation (RUSLE) for the load estimation and source apportionment of nitrogen and phosphorus was proposed. The Jinjiang River (China) was chosen for the evaluation of the method proposed here. The chosen watershed was divided into 27 subbasins. After which, the SLURP model was used to calculate land use runoff and to estimate loads of dissolved nitrogen and phosphorus, and ECM was applied to estimate dissolved loads from livestock and rural domestic sewage. Next, the RUSLE was employed for load estimation of adsorbed nitrogen and phosphorus. The results showed that the 12,029.06 t a pollution loads of total NPS nitrogen (TN) mainly originated from dissolved nitrogen (96.24 %). The major sources of TN were land use runoff, which accounted for 45.97 % of the total, followed by livestock (32.43 %) and rural domestic sewage (17.83 %). For total NPS phosphorous (TP), its pollution loads were 570.82 t a and made up of dissolved and adsorbed phosphorous with 66.29 and 33.71 % respectively. Soil erosion, land use runoff, rural domestic sewage, and livestock were the main sources of phosphorus with contribution ratios of 33.71, 45.73, 14.32, and 6.24 % respectively. Therefore, land use runoff, livestock, and soil erosion were identified as the main pollution sources to influence loads of NPS nitrogen and phosphorus in the Jinjiang River and should be controlled first. The method developed here provided a helpful guideline for conducting NPS pollution management in similar watershed. [ABSTRACT FROM AUTHOR]

It is essential to establish the water resources exploitation and utilization planning, which is mainly based on recognizing and forecasting the water consumed structure rationally and scientifically. During the past 30 years (1980-2009), mean annual precipitation and total water resource of Beijing have decreased by 6.89% and 31.37% compared with those perennial values, respectively, while total water consumption during the same period reached pinnacle historically. Accordingly, it is of great significance for the harmony between socio-economic development and environmental development. Based on analyzing total water consumption, agricultural, industrial, domestic and environmental water consumption, and evolution of water consumed structure, further driving forces of evolution of total water consumption and water consumed structure are revealed systematically. Prediction and discussion are achieved for evolution of total water consumption, water consumed structure, and supply-demand situation of water resource in the near future of Beijing using Time Series Forecasting Method. The purpose of the endeavor of this paper is to provide scientific basis for the harmonious development between socio-economy and water resources, for the establishment of rational strategic planning of water resources, and for the social sustainable development of Beijing with scientific bases. [ABSTRACT FROM AUTHOR]

Bioavailable vanadium was evaluated on the basis of soil vanadium single-extraction with ethylenediaminetetraacetic acid (EDTA), hydrochloric acid (HCl), acetic acid (HOAc), and sodium nitrate (NaNO) in Panzhihua urban park. The soil vanadium concentration extracted by HOAc was 0.01-2.07 mg kg, by EDTA 0.28-7.03 mg kg, by NaNO 0.07-0.53 mg kg, and by HCl 0.19-1.36 mg kg. The bioavailable vanadium (bioavailable fraction) obtained with HOAc was 0.01-1.33%, with EDTA 0.27-4.09%, with NaNO 0.13-0.72%, and with HCl 0.06-0.28%. In addition, the impact of soil properties, soil nutrients, and soil enzyme activities on bioavailability of vanadium is discussed in this study. Based on the characteristics of bioavailable vanadium in the soil, ecological and health risks should have been given more attention in the studied area. [ABSTRACT FROM AUTHOR]

The Aha Lake is a seasonal anoxic water system in the southwest of Guiyang City, Guizhou Province, China. Seasonal variations in SO concentrations and their isotopic compositions in lake water as well as in the tributaries were investigated in this study. The results showed that sulfate concentrations in river water range from 0.94 to 6.52 mmol/L and their δS values range from t14.9‰ and 0.9‰, while lake water has sulfate concentrations ranging from 1.91 to 2.79 mmol/L, and δS values from −9.8‰ to −5.9‰. It is suggested that coal mining drainage is the major source of SO in the Aha Lake. Rainfall, sewage discharge, sulfide oxidation and gypsum dissolution have made only limited contributions. Different depth-dependent distributions of dissolved SO and δS were developed for both DB and LJK in summer and winter. Due to water overturn, δS values display homogenous vertical distributions in winter and spring. While in summer and autumn, significant positive shifts of δS were clearly observed in epilimnion and bottom strata as a result of water stratification. High δS values in epilimnion may result from the retention of rainwater during water stratification. Dissimilatory sulfate reduction by bacteria was thought to be responsible for the increase of δS value in hypolimnion. [ABSTRACT FROM AUTHOR]

In order to investigate the impact of urbanization and industrialization on surface water quality, a pilot study of Panzhihua (攀枝花) mining town was carried out. The urbanization of Panzhihua region was dominated by industry development and population growth. The level of urbanization showed that it was 18.44% in 1965, and reached 45.99% in 1983. Then, it reached 53.71% in 2005, so the urbanization process was very rapid in Panzhihua region. In the process of industrialization, the level of industrialization was fluctuated at around 70% from 1965 to 2005, which was influenced by mining, extracting, and smelting production. In the processes of urbanization, population growth caused an increase in life pollution sources, and an amount of effluents bearing coliform, COD (chemical oxygen demand), NH-N, and BOD (five-day biological oxygen demand) were released into Jinsha (金沙) River, which could cause decline in the surface water quality. While in the processes of industrialization (especially industrial scale expansion), more effluent bearing heavy metals could cause degradation of surface water quality. Thus, the measures, such as adjusting industry structure, optimizing the cleaning technology, and controlling pollution sources, should be enhanced to alleviate the current state of water quality exacerbation. [ABSTRACT FROM AUTHOR]

In order to characterize uptake of vanadium in alfalfa grown in vanadium-cadmium (Cd)-contaminated soil, 104 soil samples and 94 plant samples were collected from pot experiment. The results showed alfalfa had strong metal adaptability (up to 400 mg kg) and high accumulation (up to 3,440.14 mg kg) of vanadium. Root had higher contents and better absorption to vanadium than overground part. Moreover, both root and overground part had direct correlation with vanadium in soil, especially with the sum of first three fractions and reducible fraction. With the increasing of vanadium, higher concentration of Cd may inhibit the absorption of vanadium in alfalfa. [ABSTRACT FROM AUTHOR]

The bacteria and plants were associated to remove diesel oil pollutants from soil. Three efficiently degrading bacteria (named strains Q10, Q14 and Q18, respectively) were isolated. Two plants (alfalfa and Indian mustard) were selected to form the association. Biodegradation of diesel oil pollutants in soil was accelerated by bacteria-plants association. The main results are summarized as follows. The plants-bacteria association was more effective in biodegradation of diesel oil pollutants in soil than in respective experiments carried out with plants or bacteria alone. Strain Q18-Indian mustard association resulted in the maximum diesel oil reduction (69.18%). The activities of catalase and polyphenol oxidase in soil were enhanced and microbial populations in soil, especially in rhizosphere, were also stimulated in the treatment of bacteria-plant association. Overall, the soil conditions might be improved by alfalfa or Indian mustard to benefit the growth of bacteria, which resulted in degradation of diesel oil pollutants more effective by the bacteria-plant association. The bacteria-plants association may be a better approach to the removal of diesel oil pollutants from soil. [ABSTRACT FROM AUTHOR]

In order to characterize environmental vanadium distribution, mobility, and bioaccumulation, a total of 55 soil samples and 36 plant samples were collected in four typical land-use districts in Panzhihua region, Southwestern China. Soil samples were analyzed with the modified Community Bureau of Reference (BCR) sequential extraction procedure, and the content of vanadium in soil and plant was determined by ICP-AES. The total content of vanadium was 208.1-938.4 mg kg in smelting area, 111.6-591.2 mg kg in mining area, 94.0-183.6 mg kg in urban park, and 71.7-227.2 mg kg in agricultural area, respectively, while the bio-available content of vanadium was characterized that the polluted areas (mining area 18.8-83.6 mg kg, smelting area 41.7-132.1 mg kg) and the unpolluted area (agricultural area 9.8-26.4 mg kg, urban park 9.9-25.2 mg kg). In addition, the contamination degree of vanadium in soil was smelting area > mining area > agricultural area ≈ urban park. Moreover, the fraction of vanadium in each sequential extraction characterized that residual fraction > oxidizable fraction > reducible fraction > acid soluble fraction. The bioaccumulation of vanadium from soil to plant was weak to intermediate absorption. Therefore, some countermeasures such as soil monitoring and remediation should be to take in the sooner future, especially in mining and smelting area. [ABSTRACT FROM AUTHOR]

A baseline might be used as a point of reference to monitor change from some specific data without concern for whether the baseline determination is natural or has been changed by human activity. We selected 326 sediment samples from Dexing area, South China, and analyzed for 17 chemical elements. The geochemical baseline was predicted with the method of the normalization procedure combined with the relative cumulative frequency curve. The results indicate Al was the best reference element for the normalization procedure among four potential reference elements (Al, Fe, Ti, and Mn). The baseline value range obtained from the normalization procedure method included both the regional geochemical background of the sediment and the median value of the measured contents. The median value of baselines obtained from relative cumulative frequency method was lower than that obtained from normalization procedure method. In contrast to the geochemical patterns of heavy metals in 1987, the spatial distribution of anomalies sprawled in 2004 in study area, especially for Cu, Pb, Zn, Cd, As, Fe, and Cr. [ABSTRACT FROM AUTHOR]

Vanadium is a trace element, which may be biologically beneficial and possibly essential but certainly harmful to human beings and some living organisms if excessive. After over 40 years of development, the mining industry has caused serious environmental problems in the Panzhihua mining area. Vanadium is significantly accumulated in the soil of the Panzhihua area. Human activities have intensified the pollution and release of vanadium and caused serious damages to the ecological system there. In the past few years, the authors have made investigations into and assessments on the geochemical distribution, chemical speciation, adsorption characteristics and transfer behavior of vanadium in the topsoil in the Panzhihua mining area. The results showed that: (1) the difference in the contents of vanadium in soil between premonsoon and monsoon is insignificant; (2) the adsorption isotherms of vanadium on soil in the Panzhihua mining area are well described by the Langmuir type; (3) the transfer ability of vanadium in soil is interrelated to soil properties; and (4) the chemical speciation of vanadium shows an order of insoluble residue > oxidizable=reducible > soluble component. According to the above results, some countermeasures to control pollution of vanadium in soil should be put forward. [ABSTRACT FROM AUTHOR]

Vanadium is a trace element widely distributed in the Earth’s crust. Naturally high levels of vanadium are recognized mainly in basic rocks and minerals, particularly in titaniferous magnetite. And the anthropogenic sources of vanadium include fossil fuel combustion and wastes including steel-industry slags. In the last few years, the authors have made investigations and assessments on the environmental geochemistry and ecological risk of vanadium in the Panzhihua mining and smelting area. In the study area, anthropogenic vanadium resulted from mining, extracting and smelting of V-Ti magnetite; vanadium pollution of topsoil and sediments occurs mainly in the mining and extracting area, smelting area, slag dumping area, tailing dam and coal mining area. In the soil, the chemical speciation of vanadium shows: insoluble residue > organically bound > Fe (amorphous) oxide-bound > Mn oxide-bound > soluble component. Vanadium pollution can cause potential harmful effects on ecological systems, and lead to animal poisoning and human disease. So vanadiam pollution should be monitored on a regular basis in the Panzhihua area. [ABSTRACT FROM AUTHOR]

Researchers are paying more and more attention to the adsorption and transport of heavy metals in soil in this study, laboratory, experiments were performed to investigate the characteristics of adsorption and transport of mercury in soils of different locations in the western suburb of Belling. To characterize the adsorption mechanism of mercury in soil, adsorption isotherms were determined through a batch experiment. Soil column experiments were performed in saturated soil under steady-state flow at a specific water head. The breakthrough curves (BTC) for the tracer (bromine) and mercury were obtained after continuous input. Moreover, two solute transport models [convection-dispersion equation model (CDE) and two-site non-equilibrium model (TSN)] were used to simulate heavy metal movement in soil on a laboratory column scale. According to the simulating results, we explored which model is more adapted to simulate the movement of heavy metals in saturated soil in the western suburb of Belling. [ABSTRACT FROM AUTHOR]

An eco-environmental geochemical investigation was carried out in and around the Dexing mining area to determine the concentrations of heavy metals in the surface water, sediments, soils and plants. The main objective of this study is to assess the environmental situation and evaluate the transferring of heavy metals from mining activities into the food chain. Some samples of water, sediment, topsoil and plant were collected along the Lean River in the Dexing mining area. The total concentrations of Cu, Pb, Zn, Cd, and As were determined by AAS, and Hg was analyzed by cold-vapor AAS. Some indices such as 'contamination degree', 'geo-accumulation index', and 'biological absorption coefficient' were used to assess eco-environmental quality. The investigation indicated a highly localized distribution pattern closely associated with the two pollution sources along the Le'an River bank: one is strong acidity and a large amount of Cu in the drainage from the Dexing Cu mining area; and the other is the high concentrations of Pb and Zn in the effluents released from many smelters and mining, processing and extracting activities in the riparian zone. Results from the investigated localities indicated, at least in part, that some problems associated with environmental quality deterioration should be solved in the future. [ABSTRACT FROM AUTHOR]

Mining and smelting activities are the main causes for the increasing pollution of heavy metals in soil, water body and stream sediment. An environmental geochemical investigation was carried out in and around the Panzhihua mining and smelting area to determine the extent of chemical contamination in soil and sediment. The main objective of this study was to investigate the environmental geochemistry of Ti, V, Cr, Mn, Cu, Pb, Zn and As in soil and sediment and to assess the degree of pollution in the study are. The data of heavy metal concentrations reveal that soils and sediments in the area have been slightly contaminated. Geochemical maps of I[subgeo] of each heavy metal show that the contaminated sites are located in V-Ti-magnetite sloping and smelting, gangues dam. The pollution sources of the selected elements come mainly from dusts resultant from mining activities and other three-waste-effluents. The are needs to be monitored regularly for trace metal, especially heavy metal enrichment. [ABSTRACT FROM AUTHOR]

Presents a study that determined geochemical baseline models and assessed the contributions of trace elements from natural and anthropogenic sources in the Panzhihua mining area in China. Background on Panzhihua; Adoption of a normalization procedure to establish geochemical baselines; Analytical results and relevant parameters for trace metals in topsoil samples from the area.