应用XCT断层扫描技术和GAN深度学习模型的多孔介质微观结构定量研究

物质在土壤中的迁移转化行为是研究地下水动力学的核心问题。定量化表征多孔介质拓扑结构并计算分析相关表面形态学参数,为研究复杂介质内物质运移微观机理提供了重要的数据基础和参数。应用微米级X射线计算机断层扫描(XCT)和图像处理技术,结合前沿的机器学习算法重建和定量分析多孔介质微观结构,可快速、批量创建高分辨率的复杂多孔介质研究样本。首先采用XCT技术,提取石英砂和散装土壤两类典型多孔介质的微观孔隙结构;而后基于生成对抗神经网络(GAN)模型重构复杂多孔介质的微观空间结构,与XCT扫描图像进行交叉验证;最后,计算获取Minkowski形态学参数,并基于多孔介质微观结构开展计算流体力学（CFD）数值模拟,计算石英砂和土壤多孔介质内的流动特征和渗透率。结果表明：1)GAN生成的合成数据与原始数据符合KS同分布,说明GAN能够成功合成与原始图像结构空间分布模式一致的图像;2)Minkowski宏观参数评价误差的较小,KS同分布结果表明,多孔介质样本的结构异质性会在一定程度上影响GAN模型的计算精度和效率;3)Open FOAM模拟计算得到的渗透率结果表明,GAN模型生成的多孔介质图像与原始图像具有...     

HPLC-ICP-MS联用分析中成药中的可溶性砷形态

建立了HPLC-ICP-MS联用技术分析三价砷、五价砷、一甲基砷和二甲基砷的方法,并应用于中成药可溶性砷形态的研究中.分别考察了牛黄解毒片、赛金化毒散、牛黄清火丸、医痫丸、乳核散结片等5种中成药,并比较了水、盐酸、磷酸、人工胃肠液和甲醇水等多种提取介质以及超声辅助和振荡等提取方式.结果表明,各种介质的提取效果差别不大,其中以1%磷酸为提取介质、超声辅助提取1h的提取率稍高,且形态不发生转化.所考察含矿物中成药的牛黄解毒片、赛金化毒散、牛黄清火丸、医痫丸中可溶性砷的比例占总砷的1%以下,主要为三价砷和五价砷,而含有海产品的中成药乳核散结片中主要为三价砷、二甲基砷和五价砷.此方法4种砷的加标回收率在90%—107%之间,平行6次提取结果4种砷相对标准偏差均小于3%。     

茶叶中砷含量特征及不同摄入方式对茶叶中砷生物可给性的影响

本研究选取不同产地不同品种的茶叶作为研究对象,分析其砷含量特征,并采用人工胃肠模拟系统,研究茶叶以不同摄入方式(茶水、原茶、粉末)进入人体对砷生物可给性的影响.结果显示,17个不同产地不同种类茶叶样品中砷含量为ND—1.16±0.03 mg·kg-1,23.5%的样品未检测出砷浓度,11.8%的样品砷含量超过绿色食品-代用茶《中华人民共和国农业行业标准》(0.5 mg·kg-1),这是因为在加工过程中硫磺熏制干燥会造成茶叶砷污染;选择含砷量较高的茶叶样品研究不同摄入方式对砷生物有效性的影响,结果表明在胃肠阶段茶水中砷生物可给性显著大于原茶和粉末的摄入方式,其中在胃阶段粉末样品砷生物可给性显著大于原茶样品砷生物可给性,而在肠阶段原茶和粉末样品砷生物可给性差异不大.茶以3种不同摄入方式进入人体,在胃肠液中溶出浓度为0.02—2.80μg·L-1,小于WHO和我国《生活饮用水卫生标准》(GB5749—2006)中砷的限量标准10μg·L-1,不会对人体造成健康风险.     

含雄黄的中成药中砷的生物可给性及其初步风险评价

为研究含雄黄中成药中砷的含量状况,探明其中砷对人体的健康风险,选取含雄黄的中成药为研究对象,分析其中砷含量;通过人工胃肠体外模拟系统研究中成药中砷的生物可给性,并在此基础上进行初步的人体健康风险评价。结果显示,含雄黄中成药样品中砷全量为9.9×102～8.8×104mg·kg-1。中成药砷的生物可给性在胃阶段为0.20%～2.17%,小肠阶段为0.26%～2.43%。以WHO每日允许摄入量(ADI)为标准的健康风险评价结果表明,若以砷全量衡量,所有含雄黄中成药均对人体健康具有巨大风险;若以小肠阶段可给砷含量评价,砷日摄入量与ADI比值范围为1.48%～879.68%,约70%含雄黄的中成药的可给砷含量仍足以威胁人体健康。     

生物样品中烷基酚类内分泌干扰物的前处理和分析方法

烷基酚类化合物具有与天然雌激素相似的结构,是一类典型的内分泌干扰物,被广泛应用于表面活性剂、纺织印染、橡胶塑料、油溶性酚醛树脂等领域,已经在环境介质中被广泛检测到.由于酚基类物质通常具有亲脂性和生物累积性,因此,生物样品中该类化合物的检测成为健康风险评价的关键.本文对近年来生物样品(生物组织、血液、尿液等)中烷基酚类物质的前处理技术与检测方法进行了综述,并对未来的发展趋势进行了展望.     

重庆市区大气颗粒物的物相组成分析

大气颗粒物组成非常复杂 ,包括晶态和非晶态的无机物与有机物 .同一个元素往往又以多种形态出现 ,而某些元素含量又较低 ,这些都给物相鉴定带来了很大的困难 .本文用Ｘ 射线衍射物相分析(ＸＲＤ)对重庆市区大气颗粒污染物的物相组成进行了研究 .在对大气颗粒物的Ｘ 射线衍射分析中 ,采用丙酮 二碘甲烷重液体系对颗粒物样品进行了密度梯度分级处理 ,鉴定出重庆市区大气颗粒物中存在的 1 0种物相 ,并初步讨论了重庆市区的污染来源和分布规律 .1　样品的采集与制备样品采集利用了ＵＶ1 3Ｈ 1型安德逊采样器及玻璃纤维膜 (采集的颗粒物为ＰＭ1 0…     

硫化氢净化强酸性高砷废液

本研究采用硫化氢为除砷药剂,向强酸性废液中通入硫化氢气体,实现砷在强酸性条件下直接去除.实验优化了反应压力、反应温度、硫酸浓度等反应条件,对沉淀絮体以及反应沉渣进行了表征,研究结果表明,在反应压力为0.22 MPa、反应温度低于55℃条件下,硫酸浓度在2%—20%范围内的含砷废液均可达良好除砷效果,废液中砷浓度可由500 mg·L~(-1)降到0.5 mg·L~(-1);废液酸度升高有利于形成密实絮体颗粒;反应产物主要为硫化砷.     

离子强度、pH对土壤胶体释放、分配沉积行为的影响

采用重力沉降法,根据司笃克斯(Stokes,1945)定律结合分速离心法提取两种粒径等级的自然土壤胶体样品.利用美国EPA批处理实验方法,进行一系列实验室静态吸附、解吸实验,并获取相应的动力学解离/沉积曲线以及热力学等温平衡解吸/吸附曲线.通过对土壤胶体释放/沉积速率、解离效率和解吸因数等行为因子的定量解析,描述自然土壤胶体的释放、稳定、沉积/分配动力学和热力学行为,考察土壤水溶液pH/离子强度、胶体粒径因素对土壤胶体释放、分配沉积行为的影响.实验结果表明,环境溶液pH的增大及离子强度的减小对土壤胶体的稳定和释放起促进作用,但对胶体向土壤颗粒中的沉积过程是不利的.pH和离子强度条件能够改变土壤胶体表面带电荷状态,改变土壤胶体与土壤介质表面吸附排斥作用力的大小,提高或降低土壤胶体与介质表面的碰撞接触效率,从而表现出土壤胶体在土壤介质中的沉积分配行为上的变化.粒径大小对土壤胶体的释放沉积行为影响明显.大粒径土壤胶体颗粒较小粒径颗粒更容易向土壤介质表面分配沉积.由此可知,土壤介质对土壤胶体持有和吸附的能力是与胶体颗粒粒径大小密切相关的,这主要是因为颗粒粒径大小能够有效的影响胶体颗粒与介质表面间的反应能量.土壤胶体沉积分配动力学曲线揭示,土壤胶体向土壤介质的分配过程是一个动态变化过程,土壤介质对土壤胶体的持留吸纳能力随时间而逐渐减弱.分配系数被证实是表征和分析土壤胶体沉积分配过程受环境物理化学因素影响的有效过程因子.     

乌达矿区煤火污染点土壤中砷的定量分析与评价

采集了矿区不同区域的72个土壤样品以及对照背景区的8个土壤样品,采用液相色谱-原子荧光联用技术测定了土壤中砷的含量,对乌达煤火污染点土壤中砷含量进行了定量分析,并对该区土壤砷污染程度进行了初步评价.结果表明,矿区土壤中砷含量范围为0.74—55.41 mg·kg~(-1),平均值12.59 mg·kg~(-1),约是该区土壤背景值(3.83 mg·kg-1)的3.29倍;不同采样点土壤中砷含量及土壤污染程度存在明显差异:烟点土壤污染点土壤非污染点土壤.乌达矿区土壤中存在砷污染,煤层自燃是该区土壤中砷污染的主要来源之一.     

土壤和植物中总砷、无机砷及有机砷的测定方法

各种价态与形态的砷的毒性差异较大,毒性顺序为砷化氢>三价砷>五价砷>有机砷。虽然有机砷的毒性最小,然而在农药施用区似乎土壤中残存有机制约占总砷量的1/2或1/3。为了确切评价砷对环境的污染,对环境样品中有机砷、无机砷和总砷分别测定是非常必要的。本文介绍的方法是利用差减法即总砷减去无机砷获得有机砷,方法简便易行,回收率为82—92％,最低检出限0.1vg砷。曾利用所拟定的方法在长期施用有机砷的果树地区采集了近60个样品进行实测,取得了良好的社会效益和经济效益,对正确评价有机砷农药的环境污染提供了一定依据。     

成都东郊稻田水中砷形态的测定及分布特征

采用氢化物发生-原子荧光光谱法测定了成都东郊4块稻田水中砷的形态.研究发现,该区域稻田表面水砷浓度平均值为3.15—7.9μg.L-1,土壤孔隙水为18.71—53.71μg.L-1,除4号稻田土壤孔隙水外,其余各稻田表面水及土壤孔隙水中砷浓度的平均值均未超出国家农田灌溉水质标准.垂直方向上,土壤孔隙水中各形态砷的浓度均比稻田表面水中的高,且都在水-土界面或接近界面处最大,然后依次向下呈递减趋势.水平方向上,各形态砷的浓度因所处稻田条件的不同而分布各异.各形态砷在所研究稻田水中的分布皆呈现出可溶态砷>颗粒态砷、三价砷>五价砷的特征.     

焦化厂污染场地表层土壤有机-矿质复合体中多环芳烃的分布

采用湿法物理分级方法将湖南省某焦化厂遗留场地表层土壤分成4种粒级的有机-矿质复合体组分,即粘粒(<2μm)、粉粒(2—20μm)、细砂(20—200μm)和粗砂(>200μm),并研究了美国EPA优先控制的16种多环芳烃(PAHs)在其中的分布特征及土壤不同有机-矿质复合体组分中有机质和矿物质组成的差异对PAHs赋存分布的影响.研究结果表明,不同粒级有机-矿质复合体中PAHs的含量顺序为粗砂>粉粒>细砂>粘粒,低环PAHs(环数≤3)在粘粒中的含量较高,达到56.3%,而高环PAHs(环数≥4)在粉粒、细砂和粗砂中的分布较高含量分别是79.37%、72.7%和71.63%,各粒级矿质复合体中PAHs含量与土壤有机碳有较好的相关性.通过对有机-矿质复合体进行X射线衍射分析发现,场地土壤粘粒和粉粒中粘土矿物含量较高,这也在一定程度上影响了污染物质在其中的分布.     

不同轮作模式对潮土团聚体及其有机碳分布的影响

为揭示不同轮作模式下潮土土壤团聚体及其有机碳含量变化规律,于2018-2019年在山西大同进行了田间试验.设置处理为油菜—荞麦(RB)、玉米—荞麦(CB)、马铃薯—荞麦(PB)和燕麦—荞麦(OB)4种轮作模式,荞麦—荞麦(BB)连作和休闲—休闲(FF)为对照,测量指标为土壤团聚体组成、稳定性和团聚体内有机碳分布.结果显示:与连作模式(荞麦—荞麦)相比,各轮作模式均提高了土壤大团聚体数量和稳定性;油菜—荞麦(RB)轮作模式0-60 cm土层的大团聚体含量均增加,其0-20 cm土层的平均重量直径(MWD)、几何平均直径(GMD)增幅为5%和7%,20-40 cm土层的团聚体R0.25、MWD、GMD值增幅为8%、26%和37%.各轮作模式土壤有机碳主要富集在土壤表层,且>3 mm粒级土壤团聚体中有机碳含量对整个土壤有机碳含量和土壤有机碳库的贡献率最高.同时,各轮作模式0-20 cm土层各个粒级团聚体的有机碳含量均显著增加,油菜—荞麦(RB)轮作模式20-40 cm土层各个粒级团聚体的有机碳含量显著增加,随粒径级数递减其增幅分别为41%、49%、72%和39%,其>3 mm粒级团聚体的有机碳储量及贡献率也最高.总之,轮作有利于增加土壤团聚体的有机碳含量,可改善土壤团聚体组成及稳定性,增加土壤的固碳能力,但不同轮作模式间有差异.本研究表明油菜—荞麦轮作更有利于土壤固碳,可以在研究区域作为重要轮作模式进行推广和应用.(图2表5参41)     

碳纳米管影响无机砷(As(III)和As(V))对大型蚤毒性的研究：特定砷形态的作用

作为一种新兴的纳米材料,羟基多壁碳纳米管(OH-MWCNTs)可能与其他污染物在水环境中共存,并进一步影响它们的毒性、输移和归趋。因此,评价碳纳米管存在下砷的毒性变化需要得到更多的关注。该试验探索了在不同pH值条件下,OH-MWCNTs诱导砷(As(III)和As(V))对水生生物大型蚤的毒性变化的潜在机制。发现了H₂AsO₃^-和H₂AsO₄^-是对大型蚤毒性最大的As(III)和As(V)。比较As(III)和As(V)的结果,发现pH值是影响砷毒性最重要的因素。此外,OH-MWCNTs影响砷对大型蚤毒性的结果表明,OH-MWCNTs的存在可以提高砷的毒性。通过吸附实验进一步研究了砷与OH-MWCNTs的相互作用。OH-MWCNTs 对As(V)吸附容量高于As(III)。总而言之, OH-MWCNTs对某些形态砷的吸附是解释砷毒性增强的可靠证据。
精选自Xinghao Wang, Ruijuan Qu, Ahmed A. Allam, Jamaan Ajarem, Zhongbo Wei, Zuoyao Wang. Impact of carbon nanotubes on the toxicity of inorganic arsenic [As(III) and As(V)] to Daphnia magna: the role of the certain arsenic species. Environmental Toxicology and Chemistry: Volume 35, Issue 7, pages 1852–1859, July 2016. DOI: 10.1002/etc.3340
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3340/full
     

The distribution and availability of phosphorus fractions in restored cut slopes soil aggregates: a case study of subalpine road,Southwest China

● There was no significant difference in soil aggregates TP along altitude gradient. ● Overall, PAC dropped steadily as aggregate size increased. ● In soil aggregate sizes, TPi > TPo > R-P at 3009,3347 and 3654 m except 3980 m. ● Active NaHCO₃-Pi was the main AP source. ● Proportion of small aggregate sizes was emphasized to increase AP storage. The distribution and availability of phosphorus (P) fractions in restored cut slope soil aggregates, along altitude gradients, were analyzed. Samples were collected at 3009, 3347, 3654 and 3980 m of altitude. We examined soil aggregates total phosphorus (TP), available phosphorus (AP) and phosphorus activation coefficient (PAC), and discovered that there was no significant difference in TP levels between all four altitudes samples (p > 0.05). However, there was a significant difference in AP at 3009, 3347 and 3980 m of altitude (p < 0.05). At the altitudes of 3009, 3347 and 3654 m, the AP accumulation in small size aggregates was more advantageous. Overall, PAC dropped steadily as soil aggregates sizes increased, as shown: PAC (3654 m) > PAC (3347 m) > PAC (3009 m) > PAC (3980 m). In all particle size soil aggregates, the distribution of the P fractions was as follows: total inorganic phosphorus (TPi) > total organic phosphorus (TPo) > residual phosphorus (R-P), at 3009, 3347 and 3654 m, but a different registry was observed at 3980 m of altitude: TPo > TPi > R-P. Through correlation and multiple stepwise regression analysis, it was concluded that active NaHCO₃-Pi was the main AP source. It was also suggested that more attention should be given to the ratio of small particle size aggregates to increase soil AP storage. In order to improve the activation capacity and supply of soil P, along with promotion of the healthy development of soil ecosystem on slope land, it was suggest that inorganic P fertilizer and P activator could be added to soil at both low (3009 m) and high altitudes (3980 m).     

Assessment of natural arsenic in groundwater in Cordoba Province,Argentina

Groundwater in the central part of Argentina contains arsenic concentrations that, in most cases, exceed the value suggested by international regulations. In this region, Quaternary loessical sediments with a very high volcanic glass fraction lixiviate arsenic and fluoride after weathering. The objectives of this study are to analyze the spatial distribution of arsenic in different hydrogeological regions, to define the naturally expected concentration in an aquifer by means of hydrogeochemistry studies, and to identify emergent health evidences related to cancer mortality in the study area. The correlation between arsenic and fluoride concentrations in groundwater is analyzed at each county in the Cordoba Province. Two dimensionless geoindicators are proposed to identify risk zones and to rapidly visualize the groundwater quality related to the presence of arsenic and fluoride. A surface-mapping system is used to identify the spatial variability of concentrations and for suggesting geoindicators. The results show that the Chaco-Pampean plain hydrogeologic region is the most affected area, with arsenic and fluoride concentrations in groundwater being generally higher than the values suggested by the World Health Organization (WHO) for drinking water. Mortality related to kidney, lung, liver, and skin cancer in this area could be associated to the ingestion of arsenic-contaminated water. Generated maps provide a base for the assessment of the risk associated to the natural occurrence of arsenic and fluoride in the region.     

焦作市大气颗粒物中水溶性砷的分布特征

利用原子荧光法对焦作市春、夏、秋、冬四季不同粒径大气颗粒物中水溶性重金属砷的分布特征及时空变化进行分析研究。研究表明：焦作市水溶性砷主要富集在PM2.1中,且颗粒物粒径越小,其富集砷的能力就越强,各级颗粒物中4级、5级、6级（0.41～2.1μm）范围内砷的含量最高,其总含量约为5.71～19.96 ng/m3,三者在不同月份所占比例高达73%～86%;由于形成机制与影响条件不同,不同粒径大气颗粒物中砷表现出明显的季节变化特征,总体趋势为冬季〉秋季〉夏季〉春季,主要原因为冬、夏季燃煤量增加,春季大气污染源减少,地表植被覆盖密集,空气环境质量较好;燃煤是焦作大气中砷的主要来源之一,且其对大气细颗粒物（粒径≤2.1μm）中砷的贡献最明显。     

Recovery and reuse of floc sludge for high-performance capacitors

• The feasibility of facile fabrication of capacitor from floc sludge is discussed. • The porous carbon composites are obtained by acidification and KOH activation. • The as-prepared 3D structure has large surface area and optimal pore size. • Admirable specific capacitance and outstanding cycling stability are obtained. In this paper, floc sludge was transformed into porous carbon matrix composites by acidification and KOH activation at high temperature and used as an electrode material for application in capacitors. The effects of different treatment processes on the electrochemical properties of sludge materials were compared. The results of electrochemical tests showed that the sludge electrode exhibited excellent energy storage performance after HNO₃ acidification and KOH activation with a mass ratio of 3:1 (KOH/C). The specific capacitance of the sludge electrode reached 287 F/g at a current density of 1 A/g. In addition, the sludge electrode material showed excellent cycle stability (specific capacity retained at 93.4% after 5000 cycles at 5 A/g). Based on XRD, FTIR, SEM, TEM, and BET surface analysis, the morphology of sludge electrode materials can be effectively regulated by chemical pretreatment. The best-performing material showed a 3D porous morphology with a large specific surface area (2588 m²/g) and optimal pore size distribution, improving ion channels and charge conductivity. According to the life cycle assessment of floc sludge utilization, it reduced the resource consumption and toxicity risk by more than 90% compared with ordinary sludge disposal processes. This work provided a cost-effective and eco-friendly sludge reuse method and demonstrated the application potential of sludge-based materials in high-performance supercapacitors.     

An assessment of sampling,preservation, and analytical procedures for arsenic speciation in potentially contaminated waters

This study was undertaken to ascertain optimal methods of sampling, preserving, separating, and analyzing arsenic species in potentially contaminated waters. Arsenic species are readily transformed in nature by slight changes in conditions. Each species has a different toxicity and mobility. The conventional field sampling method using filters of 0.45 μm in size could overestimate the dissolved arsenic concentrations, as passing suspended particles that can act as a sink or source of arsenic depending on the site condition. For arsenic species in neutral pH and iron-poor waters, the precipitation can be stable for up to 3 days without any treatment, but for longer periods, a preservative, such as phosphoric acid, is required. Also, the analytical procedure must be selected carefully because the levels and hydride generation efficiencies of arsenic in different species can vary, even for the same amount of arsenic. For arsenic speciation in samples that also include organic species, a hybrid high-performance liquid chromatography (HPLC) column and inductively coupled plasma mass spectrometry (ICP-MS) gave the best resolution and lowest detection limits. However, the procedure using a solid phase extraction (SPE) cartridge can be used economically and conveniently for analyzing samples containing only inorganic arsenic species, such as groundwater, especially that related to mine activity.     

不同价态无机砷对罗非鱼肝脏砷积累及GSH/GST解毒代谢的影响

低剂量中长期暴露下的氧化胁迫是砷对水生生物致毒的重要机制之一。本文通过对罗非鱼进行32 d的食物相砷暴露,测定不同时间点罗非鱼肝脏中谷胱甘肽(glutathione,GSH)含量和谷胱甘肽巯基转移酶(glutathione S-transferase,GST)活性,揭示不同价态无机砷对罗非鱼肝脏中GSH/GST的影响机制。经三价砷(As(III))暴露后,砷含量在2 d内显著增加而在随后的30 d内无显著性差异; 0～2 d内GSH含量显著增加,后降低,13 d后GSH含量均低于空白组; 0～6 d GST活性均大于空白组,6～8 d GST活性降低,8 d后活性高于空白组,且32 d达到最大值。经五价砷(As(V))暴露后,罗非鱼肝脏中砷含量逐渐增加,在20 d时达到最大值而后无显著性差异; 0～2 d时GSH含量降低,随后逐渐增加,在16 d达到最大值,16 d后GSH含量均低于空白组; 0～8 d时GST被大量诱导合成,8～20 d时GST合成被抑制,20 d后活性增加,在32 d达到最大值。As(III)和As(V)对罗非鱼GSH/GST的不同影响与其在罗非鱼体内的积累量有关。As(III)暴露后各时间点罗非鱼肝脏中的砷含量与GSH含量呈统计学正相关,而As(V)暴露无明显相关性。这是因为As(V)进入罗非鱼肝脏后会还原为As(III),进而GSH作为可提供巯基的还原剂而被大量消耗。另外,As(III)暴露后各时间点罗非鱼肝脏中的砷含量与GST活性呈显著负相关,而As(V)暴露却呈现出很强的滞后性,这是由于进入生物体内的As(V)需转化为As(III)后,才可直接作用于酶系统。可见,不同形态砷对水生生物的致毒机制需进一步深入研究。