Polystyrene nanoplastics aggravated ecotoxicological effects of polychlorinated biphenyls in on zebrafish (Danio rerio) embryos

In view of the accumulation of nanoplastics (NPs) in the food chain of environment and animals, and the good adsorption properties of nano-plastics to toxic substances, it is necessary to explore the influence of NPs in living organisms. In this study, single and joint toxicological effects of polystyrene nanoplastics (PS-NPs, size 80 nm) and polychlorinated biphenyls (PCBs), were explored in freshwater aquatic animal model zebrafish (Danio rerio). Our study found that exposure to single PS-NPs induced mild acute toxicity, albeit the combined exposure of PS-NPs and polychlorinated biphenyls aggravated the toxicity of PCBs in a dose-dependent manner. Results from gene expression profiling showed that NPs exposure could activate detoxification process, resulting in a slight up-regulation of antioxidant genes (sod1, gstp1), bone development genes (bmp2, bmp4) and cardiac gene (tbx20); while PCBs suppressed the detoxification through down-regulation of these genes, and the addition of NPs will exacerbate the impact of PCBs on gene suppression. Importantly, the results of in vivo purification experiments found that NPs showed prolonged retention in liver, intestine and gills of zebrafish and they might have crossed biological barrier and accumulate in lipid-rich tissues and excretion does not appear as the significant pathway for their elimination. In conclusion, the toxic effects of polychlorinated biphenyls on chorionic protected embryos were not significant as zebrafish chorion plays an important role in resisting the invasion of pollutants; PCBs can seriously damage the bone and heart development of zebrafish, while the presence of NPs significantly enhanced the toxicity of PCBs in zebrafish, which is an alarming concern for growing NPs levels and ecological safety in aquatic environment.     

Characterization of chloride transport in the unsaturated zone near salted road

The application of road salts as deicing agents contributes to the anthropogenic loading of chloride (Cl⁻) on the environment. Using a 2D solute model, the potential of the unsaturated zone to serve as a reservoir and the mechanisms controlling the movement of Cl⁻ were examined. Physical properties and initial pore-water Cl⁻ concentrations were derived from an array of soil borings. Initial pore-water concentrations show the presence of a Cl⁻ “slug” approximately 0.75 m below the surface. Simulations show that within the unsaturated zone, Cl⁻ transport is predominantly vertical, driven by molecular diffusion. After a 1-year simulation, a Cl⁻ slug similar to the background observation was noted. While Cl⁻ is retained in the unsaturated zone, a net loss of Cl⁻ from the unsaturated zone was simulated for the first 10 years. In year 11, an equilibrium between the Cl⁻ input and output is achieved. The presence of Cl⁻ in the unsaturated zone becomes a long-term source of chloride to the groundwater, which eventually discharges into the surface water. Historically, surface water chemistry data support the continual discharge of chloride to the surface water in the area, further supporting the hypothesis that the unsaturated zone serves as a Cl⁻ reservoir.     

地源热泵系统地下水热量运移阶段特性模拟研究

含水介质中地下水热量运移过程模拟是地源热泵系统这类新型浅层地温能利用工程科学论证的重要内容。通过建立饱和含水介质中热量运移对流-弥散数学模型,模拟了拟建地源热泵系统理想的对井抽-灌运行特定水流及热源条件下地下水热量运移过程。结果表明热泵系统完整运行周期(一年)内地下水热量运移过程具有显著的"阶段性"特征,"夏、冬抽-灌输运"和"春、秋停运蓄存"两阶段取决于不同的作用因素。从数学和概念模型两方面讨论了地下水流作用对热量输运过程的决定性影响,说明不同时期抽、灌井互换运行是解决拟定工作模式下热(冷)能浪费问题的理想途径。     

包气带土壤组成对三氯乙烯的吸附影响研究

有机质和矿物质是包气带土壤中的主要吸附介质,其吸附特性直接影响有机污染物在环境中的迁移、转化等过程。分别采用分析纯石英砂和典型粘土矿物高岭石模拟土壤的原生矿物和粘土矿物,利用批实验的方法研究土壤中各组成部分对三氯乙烯(TCE)的吸附行为。土壤有机质的吸附行为通过全土样和矿物质的对比得出。结果表明,粘土矿物是吸附氯代烃的主要矿物质,原生矿物对氯代烃的吸附量很小;土壤有机质含量和土壤吸附量之间有很好的正相关性;土壤有机碳含量与土壤粘土矿物含量的比值是影响吸附行为的另一重要因素,比值越小,Koc值越大,土壤对TCE的亲和力就越强。由于自然界中的土壤有机质大都与矿物质形成有机质-粘土矿物结合体,据此推测有机质-矿物质结合体会影响有机质的组成和形态,从而对其吸附行为有重要作用。     

Gaseous transport and deposition of gold in magmatic fluid: evidence from the active Kudryavy volcano, Kurile Islands

The distribution of gold in high-temperature fumarole gases of the Kudryavy volcano (Kurile Islands) was measured for gas, gas condensate, natural fumarolic sublimates, and precipitates in silica tubes from vents with outlet temperatures ranging from 380 to 870°C. Gold abundance in condensates ranges from 0.3 to 2.4 ppb, which is significantly lower than the abundances of transition metals. Gold contents in zoned precipitates from silica tubes increase gradually with a decrease in temperature to a maximum of 8 ppm in the oxychloride zone at a temperature of approximately 300°C. Total Au content in moderate-temperature sulfide and oxychloride zones is mainly a result of Au inclusions in the abundant Fe–Cu and Zn sulfide minerals as determined by instrumental neutron activation analysis. Most Au occurs as a Cu–Au–Ag triple alloy. Single grains of native gold and binary Au–Ag alloys were also identified among sublimates, but aggregates and crystals of Cu–Au–Ag alloy were found in all fumarolic fields, both in silica tube precipitates and in natural fumarolic crusts. Although the Au triple alloy is homogeneous on the scale of microns and has a composition close to (Cu,Ni,Zn)₃(Au,Ag)₂, transmission electron microscopy (TEM) shows that these alloy solid solutions consist of monocrystal domains of Au–Ag, Au–Cu, and possibly Cu₂O. Gold occurs in oxide assemblages due to the decomposition of its halogenide complexes under high-temperature conditions (650–870°C). In lower temperature zones (<650°C), Au behavior is related to sulfur compounds whose evolution is strongly controlled by redox state. Other minerals that formed from gas transport and precipitation at Kudryavy volcano include garnet, aegirine, diopside, magnetite, anhydrite, molybdenite, multivalent molybdenum oxides (molybdite, tugarinovite, and ilsemannite), powellite, scheelite, wolframite, Na–K chlorides, pyrrhotite, wurtzite, greenockite, pyrite, galena, cubanite, rare native metals (including Fe, Cr, Mo, Sn, Ag, and Al), Cu–Zn–Fe–In sulfides, In-bearing Pb–Bi sulfosalts, cannizzarite, rheniite, cadmoindite, and kudriavite. Although most of these minerals are fine-grained, they are strongly idiomorphic with textures such as gas channels and lamellar, banded, skeletal, and dendrite-like crystals, characteristic of precipitation from a gas phase. The identified textures and mineral assemblages at Kudryavy volcano can be used to interpret geochemical origins of both ancient and modern ore deposits, particularly gold-rich porphyry and related epithermal systems.     

Simulation of groundwater and nuclide transport in the near-field of the high-level radioactive waste repository with TOUGHREACT

In order to know the mechanism of groundwater transport and the variation of ion concentrations in the near-field of the high-level radioactive waste repository, the whole process was simulated by EOS3 module of TOUGHREACT. Generally, the pH and cation concentrations vary obviously in the near-field saturated zone due to interaction between groundwater and bentonite. Moreover, the simulated results showed that calcite precipitation could not cause obvious variations in the porosity of media in the near-filed if the chemical components and their concentrations of groundwater and bentonite pore water are similar to those used in this study.     

废旧电容器封存点土壤中多氯联苯的残留特征

利用气相色谱-质谱联用法(GC-MS)研究了长江三角洲某废旧电容器封存点土壤中多氯联苯(PCBs)的残留特征。利用GC-MS的选择离子监测模式(SIM)对包括7种指示性PCBs和12种类二噁英PCBs共19种PCBs进行分析。统计结果显示,该封存点土壤中19种PCBs含量为2.01～5201.20 ng/g,平均含量为229.38ng/g,明显高于国内一般土壤,但低于国内某些封存点土壤。土壤中19种PCBs同系物以低氯代(3～5氯)为主,三者占同系物总量的85.43%,尤以三氯代-PCB 28、四氯代-PCB 52和五氯代-PCB 118残留量最高。通过对比分析得出,封存点土壤PCBs以Aroclor 1242、Aroclor 1248为主,并含少量的Aroclor 1254。封存点土壤中PCBs残留量虽未超过控制值,但已呈现污染迹象,应及时采取控制措施,阻止污染趋势进一步扩大。     

洛河冲积平原包气带对入渗水污染物净化能力研究

包气带是地下水补给和地下水污染的主要通道,包气带的性质直接控制了地下水的污染化速度和程度。文章以洛阳市区洛河河床岩性(以砂砾石为主)以及由亚粘土、亚砂土、中细砂等介质构成的包气带为研究对象,分析河床和包气带对污染物的自净能力,并对其天然的自净机制进行了简要分析,结论如下:洛河河床岩性对各种污染物(NO3-除外)的净化能力均达到90%以上;亚粘土、亚砂土、中细砂等包气带介质层对重金属(Cu2+等)有很强的净化能力,而对Cl-、Cr6+的净化能力则较弱,在短时间内介质中就达到饱和而失去净化能力;在环境条件相近及水文地质条件基本相同的条件下,包气带厚度与地下水的污染程度呈负相关关系;污水经过包气带,能有效地去除污水中的有害物质,防止地下水污染。 更多还原     

Visual Modflow在石家庄市地下水硝酸盐污染模拟中的应用

利用Visual Modflow软件建立了石家庄市长达42 a的二维潜水水流模型和硝酸盐运移模型.收集整理大量地下水监测报告和研究报告提供的数据用于模型的建立,详细的地下水位和硝酸盐浓度监测数据以及不同时期的等水位线图用于模型校正.敏感度分析显示面状硝酸盐补给浓度是引起地下水NO3-浓度变化最敏感因子.利用校正的模型分3种管理方案预测了未来30 a内地下水硝酸盐浓度的变化.拟合、验证和预测结果显示该模型可作为石家庄市地下水管理的有效工具.     

多孔介质中磷负载纳米铁运动特性的模型试验

纳米零价铁在多孔介质中的运动能力影响其作为污染地下水修复材料的应用潜力。已有研究多采用一维柱试验研究纳米零价铁的运动行为,对于其二维运动行为的报道有限。自主研发了模拟多孔介质中纳米颗粒运动的模型试验系统,采用细、中、粗3种不同粒径的玻璃珠模拟土体,通过取样测量和图像分析等方法获得了磷负载纳米铁在多孔介质中的运动行为。一维柱试验结果表明磷负载纳米铁在中玻璃珠和粗玻璃珠中均有一定的运动能力,其液相回收率分别为50.3%和41.0%,而在细玻璃珠中运动能力较差;二维模型试验表明磷负载纳米铁在中玻璃珠中的滞留量随距离逐渐降低,而在粗玻璃珠中则呈现出滞留量随距离先升高后降低的趋势。由模型试验结果分析可知,磷负载纳米铁的运动和滞留过程与多孔介质孔隙结构和流速密切相关,颗粒阻塞与表面沉积等不同物理过程的共同作用导致了其在不同粒径多孔介质中运动特性的差异。研究成果可用于评估磷负载纳米铁的运动能力及分析其在多孔介质中的运移和滞留机制,为纳米零价铁技术的工程应用和环境风险评价提供参考依据。     

沙漠包气带水分运移机理研究

针对沙漠包气带的特点,运用中子仪—负压计—地温计联合观测法,对试验场典型地段水位埋深分别为lm,2m,3m的包气带含水量、水分势能和温度场进行了长期野外实地观测,并总结出相应的日变化、季节变化规律,分析了降水、蒸发等气象因素对包气带水分的影响过程,从而得出沙漠包气带水分运移机理及运移规律。为红砂岗矿区水源地水资源评价提供了科学依据。     

基于图像法的多孔介质双分子反应溶质运移模拟

采用图像分析法确定溶质浓度,以硫酸铜和EDTA二钠作为双分子反应物,在多孔介质模型中开展了不同粒径(1.52.0,2.53.0,3.54.0 mm)和流量(1.0,1.5,2.0 mL/s)下反应性溶质运移实验,探讨了应用不完全混合的对流弥散模型(IM-ADRE)对双分子反应溶质运移的模拟和预测,并进行了参数敏感性分析。结果表明:图像分析法可准确获取多孔介质中显色反应性溶质的浓度,灰度值与浓度的决定系数R²大于0.96;用IM-ADRE模型能够准确预测双分子反应性溶质硫酸铜和EDTA二钠在3种不同多孔介质中的运移过程,误差低于3.71%;实验条件的改变对IM-ADRE模型参数D、m和β₀的影响显著,说明模型参数依赖于环境条件,其变化规律需要根据实际环境条件进一步率定,便于IM-ADRE模型的进一步推广应用。     

Experimental assessment of the infiltration properties of a coarse soil medium in a dielectric infiltration test

An accurate determination of the hydrological characteristics of porous media, such as the values of the porosity and effective porosity, are essential. This is important to understand the transport processes of infiltration and the movement of water and contaminants in the porous media. In this study, a laboratory soil column experiment to estimate the porosity and effective porosity of Toyoura standard sand samples, using a dielectric method termed the frequency domain reflectometry with vector network analyzer (FDR-V), was performed. The FDR-V device uses high-frequency microwaves, ranging from 0.1 to 3 GHz, to measure the complex dielectric constants of the sample. From the measured complex dielectric constant, the two parameters of the soil samples then were derived, using a proposed dielectric mixture model and tracer concentration model. The effective porosity of the soil sample is measured at 0.311 with the FDR-V dielectric method and 0.345 by the soil tracer column test. Comparing this with the calculated porosities of the soil sample, the ratio of effective porosity is approximately 78% for the dielectric method, and approximately 86% for the tracer concentration method. These different values can be explained to be within the measurement range with regard to the measurement volume for the soil column. These results indicate that measurement by the dielectric method using an FDR-V device is an efficient and useful tool for estimating the hydrological parameters of porous media because of the dielectric response of earth materials.     

Discrete element simulation of the effect of particle size on the size of fracture process zone in quasi-brittle materials

Experimental tests performed on quasi-brittle materials show that a process zone develops ahead of a crack tip. This zone can affect the strength and the deformation pattern of a structure. A discrete element approach with a softening contact bond model is utilized to simulate the development of the fracture process zone in the three-point bending tests. Samples with different dimensions and particle sizes are generated and tested. It is shown that as the material brittleness decreases, the width of the process zone becomes more dependent on the specimen size. Furthermore, the increase in the particle size, results in increase in the width of the process zone. A dimensional analysis together with the numerical results shows that the width of process zone is a linear function of particle size (radius). This finding is discussed and compared with published experimental data in the literature.     

层状非均质结构包气带入渗过程单相流与两相流数值模拟对比研究

包气带水分入渗过程受多种因素的影响。定量研究层状非均质岩性结构和入渗速率对其影响,有助于解决根据不同条件选择单相流模型或水气二相流模型模拟包气带水分入渗过程的问题。结合填埋场等场地地层条件及污废水入渗特征,分别建立了“上细下粗”和“上粗下细”包气带层状非均质岩性结构水分入渗单相流和水气二相流模型,探讨不同层状非均质岩性结构条件下模型的适用性。在“上粗下细”岩性结构模型基础上,进一步探究入渗速率对水气两相运移结果的影响。基于论文模型研究表明：（1）在包气带岩性结构为“上细下粗”的条件下,气相的影响基本可以忽略,可直接采用单相流模型对包气带水分运移进行模拟;在“上粗下细”岩性结构和本次模型设定的底部压力保持不变及污废水泄漏前场地未接受降水入渗补给等条件下,当包气带上下层介质渗透率比值大于16倍时,气相会对水相运移产生明显影响,且下层介质渗透率越小、上下层介质渗透率比值越大,单相流与两相流的运移结果差别越大,需要采用水气二相流模型模拟包气带水分运移。（2）在包气带“上粗下细”岩性结构条件下,入渗速率越大,气相对水流入渗的阻滞作用越明显,此时包气带水分运移模拟应采用水气二相流模型。     

The use of laboratory experiments for the study of conservative solute transport in heterogeneous porous media

 Laboratory experiments on heterogeneous porous media (otherwise known as intermediate scale experiments, or ISEs) have been increasingly relied upon by hydrogeologists for the study of saturated and unsaturated groundwater systems. Among the many ongoing applications of ISEs is the study of fluid flow and the transport of conservative solutes in correlated permeability fields. Recent advances in ISE design have provided the capability of creating correlated permeability fields in the laboratory. This capability is important in the application of ISEs for the assessment of recent stochastic theories. In addition, pressure-transducer technology and visualization methods have provided the potential for ISEs to be used in characterizing the spatial distributions of both hydraulic head and local water velocity within correlated permeability fields. Finally, various methods are available for characterizing temporal variations in the spatial distribution (and, thereby, the spatial moments) of solute concentrations within ISEs. It is concluded, therefore, that recent developments in experimental techniques have provided an opportunity to use ISEs as important tools in the continuing study of fluid flow and the transport of conservative solutes in heterogeneous, saturated porous media. Received, December 1996 · Revised, July 1997 · Accepted, August 1997     

模糊均生函数残差模型在地下水数值模拟降水量预报中的应用

地下水主要补给来源为大气降水的入渗和地表水体的渗漏.在地下水模拟预报模型中需要预先知道降水量.迄今为止,年降水量的预测仍然是一个不易解决的难题.在模糊均生函数模型(FAFM)基础上,利用其残差数据序列对FAFM进行校正,提出了模糊均生函数残差模型(REMFAF),给出了模型预报精度的检验方法.实例研究表明,REMFAF模型应用于吉林省西部地区地下水数值模拟中的降水量预报,比FAFM的预报精度更高,取得了较为理想的结果.     

活动断裂调查中的高分辨率遥感技术应用方法研究

郯庐断裂带是我国东部地区最为重要的大型活动断裂之一,具有较强的发震能力,断裂带沿线多处穿过人类活动及聚集的城市。为了研究郯庐断裂带的几何展布及活动性特征,选取郯庐断裂带的沂沭断裂莒县至郯城范围为研究对象,考虑东部地区植被覆盖,采用机载激光雷达和地基激光雷达手段采集了断裂带沿线左山(一步涧)段、钟华山段、岌山段、马陵山段以及蒋家岭等地高精度地形数据,对断裂的滑动分布特征进行分析。通过对测量得到的点云数据进行点云匹配、镶嵌、植物滤除以及不规则三角网建模处理,得到了0.1 m空间分辨率的数字高程模型(Digital Elevation Model,DEM),实现了对断裂微地貌形态的高清晰度三维再现,提取了断裂断错冲沟右旋水平位错量和断层陡坎垂直位错量,结合地质填图和探槽揭露的古地震事件进行验证和对比,对郯庐断裂带莒县至郯城段的断层活动特征进行了定量分析。结果表明,沿断裂带左山(一步涧)段、钟华山段、岌山段和马陵山段的水平和垂直位错量具有分级特征,晚第四纪以来可能发生过多期(3~5次)活动和多次古地震事件。研究成果为进一步研究郯庐断裂运动学和几何学提供了重要依据,同时也说明地基激光雷达和机载激光雷达技术在活动断层研究中有着广泛的应用前景。