Heavy metal pollution in metal mining areas has emerged as a critical global environmental issue， posing a substantial threat to ecosystems and human health. This study， based on heavy metal data from mining soils in China collected between 2008 and 2022， uses methods such as the geo-accumulation index （Igeo）， Monte Carlo simulation （MCS）， and redundancy analysis （RDA） to quantitatively analyze the pollution characteristics， probabilistic health risks estimation， and influencing factors of heavy metals. The mean concentrations of Cd， Hg， Pb， As， Zn， Cu， Ni， and Cr in the soil reached 8.90， 13.41， 629.21， 135.45， 1 142.88， 215.08， 57.38， and 91.96 mg·kg-1， respectively， significantly exceeding regional background levels. Igeo assessments identified Cd， Hg， and Pb as the most severe pollutants， with 42%， 26.76%， and 19.1% of the samples classified as heavily to extremely polluted. Pollution was concentrated primarily in southern mining areas， with levels decreasing gradually from the southwest to the northeast. Health risk assessments （HRA） revealed that Cd， Hg， Pb， and As posed disproportionately higher risks to children compared to adults， with both carcinogenic and non-carcinogenic risks significantly elevated. MCSs estimated the probability of children exceeding the carcinogenic risk threshold 1E-4 at 83.66%， while for adult women and men， the probabilities were 37.74% and 31.76%， respectively. RDA highlighted economic activities and soil physicochemical properties （e.g.， pH， clay content， and cation exchange capacity） as the primary drivers of heavy metal distribution. These findings provide crucial quantitative evidence on the spatial distribution and health risks of heavy metal pollution in mining areas and support the development of targeted pollution control and health protection strategies.

Although the uncontrolled downward migration of NAPL and the expansion of the contaminated region are of particular concern, it has been shown that the remobilization of DNAPL can improve remediation efficiency by enlarging the total NAPL-water interfacial area for mass transfer during surfactant-enhanced aquifer remediation (SEAR). However, the driving forces influencing the redistribution morphology have not been sufficiently discussed. This study first combines trapping numbers (NCa and NB) with the morphological characteristics of the contaminated zone to investigate their roles in the remobilization process of DNAPL. A 2-D sandbox apparatus was used to simulate the remobilization of 1,2-dichloroethane (1,2-DCA) pooled on an arc-shaped lens with low permeability in SEAR. The area, lateral distance, and vertical distance used to characterize morphological redistribution were determined by digital image analysis. Driving forces such as viscous force, gravity force, and capillary force were analyzed using the trapping numbers: capillary number (NCa) and Bond number (NB). The results showed that the redistribution area consisted of two distinct parts, induced by remobilization of the surface layer (Part 1) and the inner layer (Part 2), respectively. In terms of pre-to-post remobilization, viscous forces played a greater role in Part 1, while buoyancy forces were more significant in Part 2 due to bypass flow. The redistribution area and lateral distance were positively correlated with the NCa of Part 1, while vertical distance had a negative relationship with NB. However, the redistribution area of Part 2 had a negative relationship with NB, so do the lateral distance and vertical distance. These results implying that trapping numbers can be used to manipulate injection parameters in SEAR, thereby promoting remediation efficiency and controlling the enlargement of the area and vertical migration simultaneously. λ Analyzed trapping forces with the trapping number, capillary number and Bond number. λ The redistribution area presented two different parts. λ Part 1 redistribution area and lateral distance had positive relationship with NCa. λ Part 2 redistribution area had negative relationship with NB.

In this work, we focus on the longterm inhibitive effect on steel corrosion in mortar contaminated by chloride. Especially, when chlorine salt is introduced with mixed water, maize gluten meal extract (MGME) can be preferentially adsorbed on steel during the process of cement setting and hardening, and what is its inhibition effect in mortar? So the influence of MGME on the corrosion rate and surface state of reinforcement was systematically analyzed by electrochemical method, FTIR, Raman and SEM-EDS. During the early cement hydration process, MGME already expelled chloride ions from preferentially adsorbed on steel surface to form a protective layer, which effectively maintained the passivation state even corroded in 3 wt% NaCl solution for 17 months. Steel surface characterizations further confirmed that MGME in mortar with 3 wt% dosage could be adsorbed enough on steel surface to shield chloride attack and protect the integrity of FeOOH passive film. Inhibition efficiency of MGME is equivalent to the most commonly used and well-known effectiveness of inhibitors as nitrites and amines, can reach 92.74-97.86%.

本研究基于1991-2018年期间的相关报道,通过单因子和内梅罗指数法、地下水质量评分法等方法及SPSS 24.0和Origin 2017等分析软件分别对我国正规、非正规生活垃圾填埋场地下水中的主要污染指标进行了评价,通过累计污染负荷比法分别对其进行了识别,并分析了正规与非正规填埋场地下水的污染特征与差异,以期为我国不同类型的生活垃圾填埋场地下水污染的修复和治理提供指导.结果表明:我国正规生活垃圾填埋场地下水中已报道检出污染指标共计89种,非正规共计93种;其中在非正规填埋场地下水中,有机物、无机盐以及重金属污染指标的数量都较之正规的更多.正规、非正规生活垃圾填埋场地下水中普遍性、局部性和点源性的主要污染指标差异明显,虽然两种不同类型的填埋场地下水中均普遍存在有机物(高锰酸盐指数)、无机盐(氨氮、氯化物、硝酸盐氮)和重金属(铁)污染指标,但是在非正规填埋场地下水中还普遍含锰和砷,局部含汞;在正规填埋场地下水中,普遍含汞,局部含锰.同时,我国正规、非正规生活垃圾填埋场地下水质量综合评分F值分别为7.69和8.11,都属于极差级别,表明无论是正规还是非正规填埋场,其地下水都已受到了严重污染,其中非正规的污染程度明显高于正规的.因此,生活垃圾填埋场对地下水的污染应引起社会的关注,尤其应加强对非正规生活垃圾填埋场地下水污染的修复和治理.

A highly smelter-contaminated and aged soil was used to study the leaching behavior of typical heavy metals induced by water inundation in batch experiments. The leaching concentration of heavy metals, Eh, pH, content of iron oxides and heavy metal speciation during the experiment were studied. The results showed that the leachate concentrations of heavy metals increased first and then decreased with the incubation time. At the first 30 days of flooding treatment, the leachate concentrations of heavy metals: Cu, Zn, Cd and Pb increased by 6.71％, 4.03％, 3.56％ and 4.55％, respectively, which was mainly due to pH decreasing, organic matter degradation and iron oxides reduction and dissolution induced by water inundation. However, leachate levels of heavy metals decreased drastically between 30 and 90 days, and remained relatively constant thereafter. At the end of flooding treatment (180 d), the leaching contents of Cu, Zn, Cd and Pb decreased by 23.78％, 16.78％, 15.48％ and 15.45％, respectively. Speciation analysis revealed that forms of occurrence of soil heavy metals changed from an acid extractable one to a reducible or oxidizable one, which decreased the activity of heavy metals. Meanwhile, increase of peak intensity for copper sulfide was observed via X-ray diffraction analysis. The decreased leachate contents of heavy metals were attributed to the adsorption of newly formed amorphous iron oxides and the chemical precipitation of sulfides and heavy metals. This study has implication for the formulation of risk control for heavy metals in contaminated soils under water inundation condition.

[Objective]Biochar has strong adsorption and fixation capacity to heavy metals in soil,which can reduce the accumula-tion of heavy metals by plants.Biochar undergoes oxidizing process under various biological and abiotic factors once it is introduced into soil.The oxidizing process makes the biochar aging which changes the physicochemical properties of biochar and thus influ-ence the heavy metals availability in soil and the accumulation of heavy metals in plants,however,the research on this filed was much limited.[Methods]In the present study,the pristine biochar was aged by oxidant-drying/wetting-freeze/thaw alternating cycle method.The cation exchange capacity (CEC),element content and surface functional groups before and after biochar aging was compared.And pot experiment was set to investigate the aging effects on the accumulation of heavy metal (Pb,Cu and Cd) in pakchoi (Brassica chinensis L.).[Results]The results showed that aging increased the CEC,O/C value and the number of hy-droxyl and carbonyl groups on the surface of biochar.Compared with the treatment without biochar addition (control group),the application of aged biochar significantly increased soil pH and the organic matter content (P<0.05).However,the bioavailable concentration of heavy metals in soil was significantly reduced by adding aged biochar.And the reducing effect was more obvious with the increasing of biochar application rate,that is,the concentration of Pb,Cu and Cd in soil decreased by 12.42%,11.67%, 11.21% for aged biochar with 5% application,respectively,compared to the control.Accordingly,the accumulation of heavy metals in the pakchoi was also significantly reduced by addition of aged biochar (P<0.05).Consequently,the contents of Pb,Cu and Cd in pakchoi without biochar treatment were 24.33 mg·kg-1 ,28.8 mg·kg-1 ,and 0.2 mg·kg-1 ,respectively,whereas those were markedly decreased to 3.33 mg·kg-1 ,7.23 mg·kg-1 ,and 0.03 mg·kg-1 under 5% aged biochar treatment.[Conclusion] Therefore,the aged biochar still effectively reduced the bioavailability of heavy metals to plants which is important to evaluate the long-term application of biochar in remediation of heavy metal polluted soil.

[背景]人工湿地处理煤炭矿井废水效果显著,而关于人工湿地沉积物的细菌群落结构和特征研究较少.[目的]阐明人工湿地净化采煤区废水的效应和细菌群落结构及特征.[方法]对山西省左云县采煤区人工湿地不同采样点水质进行监测,利用高通量测序技术对人工湿地沉积物中细菌16S rRNA基因 V3-V4区进行测序,分析沉积物中细菌群落组成.[结果]采煤区废水流经人工湿地后水质得到有效改善,其中生化需氧量(Biochemical oxygen demand,BOD5)、化学需氧量(Chemical oxygen demand,CODcr)、总氮(Total nitrogen,TN)、总磷(Total phosphorus,TP)去除率分别达到 76.2％、93.4％、73.4％和 99.3％;测序共获得 2832个操作分类单元(Operational taxonomic units,OTUs),共753个属,分布于 51个门的 150个纲;4个采样点中优势菌门为变形菌门(Proteobacteria,50％-64.7％)和拟杆菌门(Bacteroidetes,15.8％-21.2％),变形菌门中优势菌纲为 β变形菌纲和 γ-变形菌纲,其中M1 、M2,M3 中富含氨氮氧化细菌的β-变形菌纲和 γ-变形菌纲丰度最高;M4沉积物细菌 OTU最多,多样性最高;沉积物特有优势菌属 Sulfurimonas 、Sulfuricurvum的相对丰度与 NH4+-N的含量显著负相关,Azoarcus菌属相对丰度与 TN存在显著正相关,Novosphingobium菌属相对丰度与 TP含量存在显著正相关.[结论]煤矿废水流经人工湿地可得到有效的净化,细菌多样性在人工湿地生态功能中起到了决定作用.

The soil moisture regime can affect the release of heavy metals in soil. In the previous studies, slightly polluted soils or artificially contaminated soil samples were considered to investigate the effect of soil moisture. We used highly smelter-contaminated and aged soils to study the release of typical heavy metals (Cu, Zn, Cd and Pb) induced by water incubation in batch experiments with characterization via speciation and X-ray diffraction analyses (XRD). The results show that the leachable concentrations of the heavy metals increased slightly in the first 30 days, decreased drastically between 30 and 90 days, and immobilized relatively constant thereafter. The fluctuation was ascribed to the changes of soil Eh and pH, the reductive dissolution of crystalline iron oxides, the formation of new amorphous iron oxides, the absorption of dissolved organic matter and the precipitation of metal sulfide. Speciation analysis indicated that a proportion of the soil heavy metals was transformed from an exchangeable fraction to a less labile fraction after water incubation. And the presence of a lead iron oxide phase and the peak increasing of zinc sulfide were observed via XRD analyses. Finally, water incubation restrained the release of heavy metals after 180 days of incubation, and reduced the leachability of Cu, Zn, Cd and Pb by as much as 1.61%–7.21% for soil A and 0.43%–3.36% for soil B, respectively. The study findings have implications for the formulation of risk control and management strategies for heavy metals in smelter-contaminated soils.

Metal pollution in urban soils due to smelting and electroplating has become a severe problem in China. In this study, the concentration, chemical fraction, and leaching behavior of typical metals (Cu, Zn, Cd, and Pb) in soil samples from ten metallurgical sites were studied. The results show that some of the soils were polluted with Cu and most were heavily polluted with multiple metals, especially Zn, Cd, and Pb. The average concentration of Cu, Zn, Cd, and Pb was 498, 4145, 89, and 5091 mg/kg, respectively. Chemical fractionation revealed that Cu, Zn, Cd, and Pb were mainly present in the acid-soluble fraction in polluted soils, but predominated in the residual fraction in unpolluted soils, demonstrating that allogenic metals in the soils were mostly present in the more labile fractions. Toxicity characteristic leaching procedure results were in agreement with the chemical fractionation study, indicating that the higher the total metal content, the higher the leachability, mobility, bioavailability, and potential toxicity to the environment, especially groundwater. Use of chemical fractionation results instead of total metal concentrations would provide better insight into the distribution and binding forms of metals for better assessment of their mobility and bioavailability. The study would provide much more important information for developing better remediation strategies for contaminated sites.

Tibetan medicine Herpetospermum caudigerum Wall. (HCW) has long been employed to treat hepatitis, inflammatory diseases and jaundice according to the records of “The Four Medical Tantras” in China. This study was investigated to explore the protective effects of HCW on hepatic fibrosis and the possible mechanism in a rat model. Hepatic fibrosis was established by intragastric administration of 3 ml/kg carbon tetrachloride (CCl4) twice a week for 6 weeks. CCl4‐treated rats were received HCW (1 and 3 g/kg/d) and silymarin (0.1 g/kg/d) from 3 to 6 weeks. The results showed that HCW could significantly decrease the levels of AST, ALT, HA, LN, PCIII, Col IV, TNF‐α, IL‐1β and IL‐6. Moreover, HCW could effectively inhibit collagen deposition and reduce the pathological damage. Analysis experiments finally exhibited that HCW was able to markedly inhibit hepatic fibrosis by modulating the expressions of NF‐κB p65, IκBα, Samd3 and TGF‐β1 proteins. Therefore, our results suggest that HCW has hepatoprotective activity against CCl4‐induced hepatic fibrosis in rats by regulating the inflammatory responses.

A sequential extraction method for phosphorus was modified according to modified Tessier sequential extraction sequential,to increase extraction rate of Fe bound P and A1 bound P,and to analyze organic P and inorganic P in sediments simultaneously.The extraction sequence in optimal modified sequential extraction method for P was as loosely adsorbed P,authigenic carbonate bound P (pH=5.0),Fe bound P,A1 bound P,detrital apatite P and residue P.Extraction rate of Fe and A1 through the optimal modified sequential extraction method for P is higher than sequential extraction method un-modified.Concentration of authigenic carbonate bound P determined by the optimal modified sequential extraction method is similar to that determined by un-modified sequential extraction method.Difference was observed between liable organic phosphorus concentration,as well as resistant organic phosphorus concentration,obtained from the optimal modified sequential extraction method and that obtained from modified Bowmen-Cole method.Nevertheless,concentration of moderately liable organic phosphorus,the largest proportion of organic phosphorus,determined by the optimal modified sequential extraction method is similar to that determined by modified Bowman-Cole method.Significant difference was not found between proportion of bio-available phosphorus in the total phosphorus of surficial sediments collected from Dongting Lake estimated based on the optimal modified sequential extraction method and proportion estimated according to un-modified sequential extraction method.

During the process of surfactant enhanced aquifer remediation (SEAR), free phase dense non-aqueous phase liquid (DNAPL) may be mobilized and spread. The understanding of the impact of DNAPL spreading on the SEAR remediation is not sufficient with its positive effect infrequently mentioned. To evaluate the correlation between DNAPL spreading and remediation efficiency, a two-dimensional sandbox apparatus was used to simulate the migration and dissolution process of 1,2-DCA (1,2-dichloroethane) DNAPL in SEAR. Distribution area of DNAPL in the sandbox was determined by digital image analysis and correlated with effluent DNAPL concentration. The results showed that the effluent DNAPL concentration has significant positive linear correlation with the DNAPL distribution area, indicating the mobilization of DNAPL could improve remediation efficiency by enlarging total NAPL-water interfacial area for mass transfer. Meanwhile, the vertical migration of 1,2-DCA was limited within the boundary of aquifer in all experiments, implying that by manipulating injection parameters in SEAR, optimal remediation efficiency can be reached while the risk of DNAPL vertical migration is minimized. This study provides a convenient visible and quantitative method for the optimization of parameters for SEAR project, and an approach of rapid predicting the extent of DNAPL contaminant distribution based on the dissolved DNAPL concentration in the extraction well.

对于地下水中的1,2-DCA（1,2-dichloroethane,1,2-二氯乙烷）,表面活性剂强化抽出处理是一种十分有效的修复技术.为明确表面活性剂浓度、介质粒径及抽出速率等因素对1,2-DCA修复效果的影响,选取石英砂作为多孔介质,1,2-DCA作为DNAPLs（dense nonaqueous phase liquids,重质非水相液体）代表,SDBS（sodium dodecylbenzenesulfonate,十二烷基苯磺酸钠）作为表面活性剂代表,在二维可视化砂箱中采用染色示踪结合图像分析技术对汇于凹陷弱透水层上的1,2-DCA开展SDBS强化抽出处理试验.结果表明:SDBS对1,2-DCA具有显著增溶作用.4组纯水试验的抽出液中ρ（1,2-DCA）最大值为219.15 mg/L,加入1倍CMC和3倍CMC（CMC为临界胶束浓度）的SDBS后,ρ（1,2-DCA）最大值分别升至650.95和800.44 mg/L.1,2-DCA去除总量随ρ（SDBS）的升高而增加,其中加入3倍CMC的SDBS条件下1,2-DCA的去除总量是纯水试验条件下的1.44~2.06倍.细粒径中的毛细力比粗粒径中更大,并且1,2-DCA的最大污染面积是粗粒径条件下的2.18~3.14倍,1,2-DCA与SDBS溶液接触面积的增大有利于提高SDBS对1,2-DCA的去除效果.同时增加抽出-回注流量可以扩大1,2-DCA与SDBS溶液的接触面积,提高1,2-DCA向溶液中的传质效率,进而提高1,2-DCA的去除效果.研究显示,SDBS强化抽出处理技术能够显著提高地下水中1,2-DCA的去除总量和去除效率.

To address devastating land desertification and soil erosion and to improve human well-being, central government in China has implemented a number of ecological restoration programs. It is essential to rigorously monitor the dynamic of vegetation activity and evaluate the effectiveness of these programs, not only to provide scientific support for ecosystem monitoring in arid and semi-arid region, but also to assess the efficiency of ecological restoration policy. Taking Inner Mongolia as study area, we used 13 years (2000-2012) of both climatic data and MODIS NDVI data to (1) assess the spatiotemporal vegetation dynamic and map areas of significant vegetation restoration and degradation, (2) analyze the impacts of climatic changes on vegetation activity and map areas where vegetation activity dynamic was significantly affected by climatic change, (3) map main driving forces of significant vegetation restoration or degradation, (4) validate the zones where vegetation significant restoration were mainly impacted by ecological restoration programs with vegetation fractional cover data in 2000 and 2012. Results showed an overall greening (15.38% significant NDVI increasing) and partial degradation (1.64% significant NDVI decreasing) in Inner Mongolia. It was estimated that annual precipitation most strongly and significantly limited vegetation growth over 45.1% of Inner Mongolia, whereas sunlit hours significantly limited growth over 3.37% and air temperature significantly over 0.73% of Inner Mongolia. Among the 15.38% significant greening region, 5.86% was caused by climatic changes, 5.67% was caused by ecological restoration programs, and the other 3.8% was caused by multi-factors. Among the 1.64% significant degradation region, 0.17% was caused by climatic changes and other 1.47% can be explained by human activities, such as population growth and city expansion. (C) 2015 Elsevier B.V. All rights reserved.

Aiming at studying the ecological security in Wenchuan, China, where the ecological system had been greatly damaged by the earthquake in 2008, an evaluation indicators system was established based on the pressure–state–response (PSR) model, and the indicators were derived from remote sensing images, meteorological data, and statistical data. Ecological security indexes in 2007, 2008, and 2013 were calculated through a comprehensive index method. Then the spatio-temporal analysis on ecological security was conducted. Particularly, the changes of ecological security were centrally analyzed concerning topography, land use types, vegetation coverage, as well as ecological PSR. It is found that the ecological security in Wenchuan presented a distinct vertical-belt distribution. It was damaged by the earthquake, however, it had been improved obviously by 2013, which still did not reach the level in 2007. Meanwhile, the epicentre, the Minjiang River and the southwestern mountains have typically regional characteristics, where the changes of ecological security were analyzed elaborately. The ecological security of these regions had been differently restored compared with 2007. However, there were still some regions with unsafe ecological security. Finally, the studied area was divided into four regions with different protection strategies and some recommendations were provided for further ecological protection.

Four typical NAPLs were selected for vertical infiltration experiments conducted in two-dimensional visible sandbox apparatus.Totally 75 images were captured by the digital camera to have the front infiltration morphological information.Fractal dimension was used to estimate the effective interfacial tension for finger spacing prediction.In addition,finger spacing predicted by the means of capillary pressure head was compared with the predictions by fractal dimension.The results showed that predictions by the capillary pressure head method deviated more from the observed finger spacing,with the absolute error values varied between 1%-93% while the prediction errors by fractal dimension were between 2%-25%.NAPLs denser than water have quite high prediction errors calculated by the capillary pressure head method.The predicted finger spacing showed a significant linear correlation with those observed in practice.Compared with the capillary pressure head method,the fractal dimension method predicted more precisely especially for DNAPLs,which could be used for unstable finger flow prediction in the contaminated soil risk management and in the effective design of recovery and remediation schemes.

Dyes are frequently used to visualize fingering flow pathways, where the image process has an important role in the result analysis. The theory of fractal geometry is applied to give quantitative description of the stain patterns via image analysis, which is helpful for finger characterization and prediction. This description typically involves two parameters, a mass fractal dimension (D(m)) relative to the area, and a surface fractal dimension (D(s)) relative to the perimeter. This work detailed analyzes the influence of various choices during the thresholding step that transformed the origin color images to binary ones which are needed in the fractal analysis. One hundred and thirty images were obtained from laboratory two-dimension sand box infiltration experiments of four dyed non-aqueous phase liquids. Detailed comparisons of D(m) and D(s) were made respectively, considering a set of threshold algorithms and the filling of lakes. Results indicate that adjustments of the saturation threshold influence are less on both D(m) and D(s) in the laboratory experiments. The brightness threshold adjustments decrease the D(m) by 0.02 and increase the D(s) by 0.05. Filling lakes influence the D(m) less while the D(s) decrease by 0.10. Therefore the D(m) was recommended for further analysis to avoid subjective choices' influence in the image process.

The infiltration characteristics of toluene, diesel, 1, 2-dichloroethane and tetrachlorethylene were studied in four different unsaturated porous media to determine the impact of the properties of media and fluids on the infiltration aided by digital image analysis technique. The results indicated that the whole process of NAPLs migration can be recorded dynamically using the digital image analysis technique. The unstable flow "fingering" occurred in the process of infiltration. Fingering mechanisms such as splitting, coalescing, and shielding were observed in the process of fingering. Front morphology of the infiltration was influenced by the properties of porous media and fluids. The vertical migration rates and the growth rates of area development were positively correlated to the size of medium particle and the density of the NAPLs (except for toluene) in the process of infiltrating. The number of fingers and the wavelength of fingering were also closely correlated with the properties of media and fluid. DNAPLs infiltrated faster compared with LNAPLs, which resulted in larger pollution area within the same infiltration time. It can be concluded that the environmental risk of DNAPLs is significantly greater than the LNAPLs.