垃圾渗滤液水溶性有机物对污染土壤中重金属Pb迁移性的影响

采用土柱淋滤试验研究了不同填埋年限的垃圾渗滤液DOM在土壤中垂直迁移及其对土壤重金属Pb淋滤溶出的影响。结果表明,不同填埋年限(0.4~5.12 a)的垃圾渗滤液DOM在土壤中垂直向下的迁移速率存在差异,填埋时间短的垃圾渗滤液DOM在土壤中迁移性较强。与对照相比(不加渗滤液DOM),垃圾渗滤液处理对红壤中土壤重金属Pb的累积解吸率高74.25%;在潮土上高-38.79%,且垃圾填埋年限中期的渗滤液DOM对土壤重金属的溶出影响更显著,说明垃圾渗滤液DOM进入土壤环境对重金属的迁移有促进作用。     

广西合山煤矸石重金属的淋溶实验及环境效应

准确掌握煤矸石中重金属元素的溶出特征与释放规律对评价与防治煤矸石对土壤与地下水环境污染具有重要意义。笔者选取广西合山市里兰矿区的大型煤矸石堆(GD06)为研究对象,通过对煤矸石静态浸泡和动态淋滤的实验研究,揭示煤矸石中8种典型的有害重金属元素As、Cd、Cr、Cu、Mn、Ni、Pb、Zn在不同pH值、不同环境温度、与降水的不同作用方式下的溶出特征与释放规律。结果表明,煤矸石在静态浸泡过程中除未检出Mn外,其他7种重金属元素的溶出浓度随浸泡时间的延长而增加,表现出前期的快速释放和后期的慢速释放规律;而浸泡温度升高后,部分重金属元素如Cr、Cu、Pb在浸泡后期的释放速率呈增加趋势。动态淋滤过程中8种重金属元素表现出间歇性快速释放规律,且溶出浓度大于静态浸泡方式,对环境的影响更显著。pH值和温度是煤矸石静态浸泡重金属元素溶出特征的重要影响因素,重金属元素的溶出浓度随温度升高而增加,随pH值减小表现出不同的溶出特征与释放规律。Zn、Ni、Cd和As在静态浸泡和动态淋滤实验中的释放量和释放率较大,是煤矸石淋滤液中最易污染土壤和地下水的重金属元素。     

冻融作用对黑土和棕壤中Pb、Cd吸附/解吸特征的影响

冻融作用对土壤理化性质具有重要影响,进而影响了土壤中重金属迁移转化过程和环境效应。通过实验模拟研究了冻融作用对黑土和棕壤中Pb、Cd吸附/解吸特征的影响。结果表明：黑土对Pb和Cd的吸附能力大于棕壤;冻融作用降低了土壤对Pb和Cd的吸附能力,这与冻融作用改变了土壤的理化性质有关;随着Pb和Cd吸附量的增大,黑土和棕壤中Pb和Cd的解吸量和解吸率也相应增大;冻融作用促进了黑土和棕壤中Pb和Cd的解吸,并且在同一冻融条件下黑土的解吸能力小于棕壤;冻融作用使得黑土和棕壤对Pb和Cd的解吸量大于未冻融土壤,这与冻融作用使解吸溶液pH的下降幅度增大有关。冻融作用降低了土壤对Pb和Cd的固持能力,增加了土壤中Pb和Cd的生态风险。     

环境因素对港口矿石堆场中矿产品重金属溶出的影响

随着中国经济发展,港口矿产品堆场重金属溶出作为港口土壤、水体的重要污染源不容忽视,重金属的溶出量与重金属种类有关。本文以天津港口矿石堆场中多类矿石为研究对象,通过静态浸泡实验,根据重金属的溶出情况确定典型矿产品和典型重金属因子,研究了时间、pH和温度对于典型矿产品中重金属溶出的影响。结果表明：铅精矿和铜精矿的重金属溶出量大,铅精矿中的Zn、Pb、Cd和铜精矿中的Ni是典型重金属因子,相应的溶出量比其他重金属高出1~3个数量级。随着时间的增加,铅精矿中Zn、Pb、Cd的溶出浓度增大,而铜精矿中Ni的溶出浓度基本上保持稳定。在pH 3.5~7.5的范围内,铅精矿中Zn、Pb、Cd和铜精矿中Ni的溶出浓度随pH值的变化均无显著性差异,且受pH的影响不大。在20~40℃的温度范围内,铅精矿中Zn、Pb、Cd的溶出浓度大体随温度升高而升高;铜精矿中Ni的溶出浓度则在30℃后呈现下降的趋势。本文初步探究了矿产品中重金属溶出的基本规律,为港口矿石堆场中矿产品重金属溶出的监控和防治提供了数据支持。     

盐酸提取条件下土壤重金属元素的释放特征

采用河南省黄淮海平原典型农田土壤样品,开展了不同浓度盐酸(1,0.1,0.001,0.000 01 mol/L)和振荡时间(2,24,48,96 h)的土壤重金属元素提取实验,分析了盐酸浓度和振荡时间等对土壤重金属元素释放的影响,探讨了不同提取条件下土壤重金属元素的释放效果及其影响因素。研究表明:土壤Cr、Cu、Ni、Zn和Pb采用1 mol/L盐酸振荡48 h时萃取率显著高于其他处理,其中Pb的萃取率最高,土壤As采用1 mol/L盐酸振荡2 h时萃取率最高,碱性土壤Cd采用0.1 mol/L盐酸振荡2 h时萃取率最高。在此基础上,根据1 mol/L盐酸振荡2 h的提取结果,采用统计分析方法分析了土壤重金属元素全量、理化性质以及土壤类型对土壤重金属元素释放的影响,结果表明:土壤Cr全量越高,Cr萃取率越高;土壤干密度越大,Pb萃取率越高;土壤pH值越低,土壤Ni萃取率越高,而土壤Pb正好相反;土壤有机质对重金属元素萃取率无统计上的显著影响;Cu、As、Pb在碱性土壤(黄河流域)萃取率相对较高,而Cr、Ni、Zn在酸性土壤(淮河流域)萃取率相对较高;土壤类型对重金属元素释放的影响表现为砂姜黑土Cr,水稻土Cu、Ni、Zn,潮土As、Pb的萃取率相对较高。     

长春市土壤中Pb含量、化学形态和空间分布及其影响因素

以长春市7个功能区,30个采样点土壤为研究对象,研究城市土壤中Pb含量、化学形态与土壤物理化学性质的关系。结果发现:长春市土壤重金属Pb污染严重,主要以残渣态和有机结合态为主。不同功能区Pb含量及化学形态差别很大。土壤物理化学性质对Pb及各种化学形态含量影响程度明显不同,通过逐步回归方法确定主要影响因子,且建立土壤中Pb富集及其化学形态预测模型。     

陕西潼关县金矿矿区周边农田土壤重金属生态健康风险评价

为了解潼关金矿矿区早期粗放式的矿业活动对矿区周边农田土壤的重金属污染状况的影响以及对暴露人群的不良健康效应的评价,采用地质调查工程选取了矿区附近6块农田土壤为研究对象,通过X射线荧光光谱分析法测定了68个土壤样本中Cd、Hg、As、Pb、Cr、Cu、Ni、Zn等8种土壤重金属含量,采用地累积指数法、潜在生态危害指数法和健康风险评估模型分别评价该区土壤重金属污染程度、潜在生态风险和人体健康风险。结果表明,该区农田土壤中Cd、Hg、Pb、Cu、Ni、Zn 6种重金属平均值高于潼关县土壤背景值,呈现不同程度的积累;Pb、Hg、Cd的土壤积累含量不仅超出了土壤重金属污染对农产品质量存在安全风险的最低限值农用地土壤污染风险筛选值,还分别以41.2%、72.1%、14.7%的超标率超出了土壤重金属污染对农产品质量存在安全风险的最高限值农用地土壤污染风险管制值;研究区土壤重金属污染评价显示,土壤中Hg、Cd、Pb总体污染程度最重,Cu、Zn总体呈现轻—重污染,Ni、Cr、As总体呈现无污染状态。生态风险评价显示,Hg、Cd、Pb为主要生态危害元素,Hg为极强风险,Cd和Pb为强风险。人体健康风险表明,研究区重金属对儿童的非致癌风险显著,Pb、Hg为主要非致癌因子;致癌风险均在合理范围,Cd致癌风险最大,手-口摄入为最主要的暴露途经,儿童更易受到重金属污染威胁。     

成都市东区大气总悬浮颗粒物(TSP)质量浓度及其重金属分布特征

大气总悬浮颗粒物(TSP)中的重金属污染物具有不可降解性,可经由干湿沉降转移到地表土壤和地表水体中,通过一定的生物化学作用,进入动植物体内,严重危害人体健康。研究了成都市东区TSP质量浓度,以及颗粒物重金属元素的浓度分布特征,并对该区重金属进行了污染评价。结果表明,2015年研究区大气TSP的年平均浓度为0.219 9mg/m3,略超过国家二级标准规定的年均浓度限值。研究区TSP平均质量浓度的变化为冬季春季秋季夏季,呈现明显的季节变化。富集因子分析表明,TSP中重金属Pb、Zn、Cd、Cr、Ni、Cu富集程度不一,其中Cd、Cu、Zn和Pb元素人为来源明显。     

内蒙古废弃钨钼矿区周围土壤重金属污染生态环境评价及成因分析

为研究内蒙古赤峰市废弃钨钼矿区周围土壤重金属污染特征、潜在生态风险及成因分析，共采集83份表层土壤样品和6个土壤钻孔。采用ArcGIS空间插值分析方法研究As、Cd、Cr、Cu、Ni、Pb、Mo和Zn的空间分布，构建重金属扰动指数函数研究重金属受人类活动的污染程度，利用地累积指数法验证矿区周围土壤重金属污染程度，通过相关性分析判断重金属来源并讨论污染成因。结果表明：矿区周围土壤As、Cd、Cu、Pb、Zn和Mo平均含量明显高于矿区周边背景值，高含量主要分布尾矿库周围，主要来源为矿山采选活动；Cr和Ni基本无污染，主要来源为母岩风化。通过重金属扰动指数函数计算发现：采用区域背景值对矿区周围进行重金属污染评价夸大了矿山采选活动对矿区周围土壤重金属的污染，矿区周围土壤重金属污染是由于天然重金属富集和采矿活动共同作用下的“双驱动模式”导致，尾矿库周围土壤重金属污染程度随着与尾矿库水平距离的增加和深度的加大而逐渐降低。降水量丰富程度是影响重金属迁移能力的关键因素，该矿处于降水量匮乏地区，尾矿库对周围土壤重金属污染范围有限，对生态环境影响轻微。     

湘西金矿尾矿—水相互作用：1．环境地球化学效应

湘西金矿在生产过程中产生了大量的尾矿。该区尾矿－水相互作用强烈，并引起了尾矿中重金属元素的释放、迁移和对水体－土壤、蔬菜等表生环境的重金属污染。污染程度较大的元素均为Au、Sb、As、Cd、Hg、W等，与尾矿中元素的富集特征相一致。尾矿中重金属元素的水迁移能力由大到小顺序为Au、Cd、W、Sb、Pb、As、Zn、Cu。元素的生物吸收系数由大至小顺序为Cd、Au、Zn、Hg、Sb、Cu、Pb、As、W。植物中金属元素浓度主要受土壤中的浓度、植物种类和吸收的影响。     

冻融循环下含磷材料固化锌铅污染土的强度及溶出特性研究

采用新型含磷材料（KMP）及水泥（PC）固化稳定化锌（Zn）、铅（Pb）重金属污染土,研究试验土经冻融循环后的毒性浸出（CLP）、无侧限抗压强度（UCT）、压汞试验（MIP）及化学形态分析（BCR）,探究固化污染土的力学特性及耐久特性。试验结果表明,经冻融循环后,未处理污染土Zn、Pb浸出值均超过中国土壤标准;采用KMP和PC固化后,Zn、Pb浸出浓度明显低于未处理污染土;KMP固化污染土比PC固化污染土重金属固化效果更为显著,并能达到中国土壤标准;与常规养护相比,冻融循环之后的固化土体强度明显减小;经过12级冻融循环的KMP固化复合Zn、Pb重金属污染污染土强度高于PC固化试样8.6倍。压汞试验表明,经12级冻融循环后固化污染土孔隙体积增大,化学形态分析结果表明,采用KMP、PC固化重金属污染土中可交换态Zn随着养护龄期的增长而减少,残渣态Zn增加。     

Combination of ICP-AES and Instrumental Neutron Activation Analysis as Effective Methods for Studying Distribution of Elements in Soil and Plants

A detailed characterisation was carried out for soil sampled from sites with different levels of contamination before and after the cultivation of oats and barley. Mineralogical composition, concentration of exchangeable cations, dynamics of soil pH and acid neutralisation buffer capacity of the soil were studied. A total of 21 elements in the soil and 28 elements in the plants were determined by instrumental neutron activation analysis. Distribution of Al, Cr, Mn, Fe, Co, Ni, Cu, Zn and Pb in soil leachates was studied by sequential leaching procedure and ICP-AES. It was found that plants significantly affect most of the soil characteristics including the leaching of heavy metals.     

Distribution of Cd,Pb, Zn and Cu and their chemical speciations in soils from a peri-smelter area in northeast China

An exploratory study on soil contamination of heavy metals was carried out surrounding Huludao zinc smelter in Liaoning province, China. The distribution of total heavy metals and their chemical speciations were investigated. The correlations between heavy metal speciations and soil pH values in corresponding sites were also analyzed. In general, Cd, Zn, Pb, Cu and As presented a significant contamination in the area near the smelter, comparied with Environmental Quality Standards for Soils in China. The geoaccumulation index showed the degree of contamination: Cd > Zn > Pb > Cu > As. There was no obvious pollution of Cr and Ni in the studied area. The speciation analysis showed that the dominant fraction of Cd and Zn was the acid soluble fraction, and the second was the residual fraction. Pb was mostly associated with the residual fraction, which constituted more than 50% of total concentration in all samples. Cu in residual fraction accounted for a high percentage (40–80%) of total concentration, and the proportion of Cu in the oxidizable fraction is higher than that of other metals. The distribution pattern of Pb and Zn was obviously affected by soil pH. It seemed that Pb and Zn content in acid solution fraction increased with increasing soil pH values, while Cd content in acid soluble fraction accounted for more proportion in neutral and alkaline groups than acidic one. The fraction distribution patterns of Cu in three pH groups were very similar and independent of soil pH values. And the residual fraction of Cu took a predominant part (50%) of the total content.     

Using robust kriging and sequential Gaussian simulation to delineate the copper- and lead-contaminated areas of a rapidly industrialized city in Yangtze River Delta,China

A total of 540 topsoil samples (0–15 cm), 188 subsoil samples (20–40 cm), and four individual soil profiles were collected in this study for mapping the Cu- and Pb-contaminated areas in soils of Zhangjiagang city, an industrialized city in the Yangtze River Delta region of China. Robust geostatistical methods were applied for identifying possible spatial outliers of Cu and Pb data, and then a sequential Gaussian simulation was employed for delineating the potential areas where Cu or Pb concentration was affected by diffuse pollution. The results showed that the spatial outliers of Cu and Pb were strongly associated with various types of factories. The anthropogenic input of Cu to soils at local hotspots was closely related to emissions of printing and dyeing, metallurgical, and chemical factories, whereas a lead oxide factory and a chemical factory resulted in a considerable increase of Pb in the topsoil of the study area. Approximately 30% of the total land area of the study was at potential risk from the Cu or Pb diffuse pollution resulting from rapid industrialization of the area over the past 20 years.     

Risk of metal mobility in soils from a Pb/Zn depleted mine (Lugo,Spain)

The risk of Pb, Zn and Cd mobility is evaluated in soils from a depleted mine at Rubiais (Lugo, Spain). This area is under special protection because of its outstanding natural value. Soils from nine different areas were selected: at the mining zone (R1, R2, R3), at minespoils (R4, R5, R6) and soils developed on the settling pond (R7, R8, R9). A control soil (RC) was sampled outside the mine. The objectives are (i) to study the characteristics of soils with high influence on metal retention, (ii) to determine the content of Pb, Zn and Cd comparing it with the generic reference levels, and (iii) to evaluate the distribution and the interactions between the metals and the soil geochemical phases by means of sequential chemical extraction, X-ray diffraction, field emission scanning electron microscopy/energy-dispersive X-ray spectroscopy (FE-SEM/EDS) and time of flight secondary ion mass spectrometry (TOF–SIMS). The concentration of Pb, Zn and Cd ranges 850–6,761, 1,754–32,287 and 1.8–43.7 mg kg^?1, respectively, and the highest proportion is in the residual fraction. The Mn oxides highly influence the retention of Cd while Pb retention is mainly influenced by Fe oxides. Zn is uniformly distributed amongst the residual fraction and the Fe and Mn oxides. TOF–SIMS and SEM/EDS techniques confirm the fractionation results, showing how Pb and Zn are as sulphide and associated with Fe and Mn oxides. Nevertheless, care should be taken since oxides and sulphides could suffer sulphide oxidation processes or alteration of the oxides causing leaching and the contamination of the protected ecosystem.     

湘江入湖河段沉积物重金属污染及其Pb同位素地球化学示踪

湘江是我国重金属污染最严重的河流之一.本次工作利用等离子质谱(ICP-MS)和多接收同位素质谱(MC-ICP-MS)等技术,对湘江入湖河段沉积物进行了系统的重金属微量元素和Pb同位素分析.结果表明,湘江河床沉积物明显富集Bi、Sc、V、Mn、Ni、Cu、Zn、Pb、Cd、Sn、Sb等多种重金属微量元素,而湖盆沉积物重金...     

模拟酸雨及施磷对水稻土中铅的淋溶特性影响

采用pH=3.0、pH=4.5与对照pH=5.6的3种模拟酸雨淋溶土柱的方法,研究酸雨及含磷酸雨淋溶下合肥市郊水稻土中铅的释放特征与规律。结果表明:经过相当于1 980 mm降水量的淋溶后,铅释放量总体上表现为随着酸雨强度增加累积淋溶量也增加的现象。酸雨作用下,施磷量越多土壤中铅的淋失总量越大。在酸雨及施磷条件下,大兴地区黄褐土中Pb较义城地区水稻土中易于淋失。     

冻融循环作用下层理砂岩物理特性及劣化模型

岩石在冻融环境下发生的损伤与其层理结构密切相关,同时冻融损伤作为一种综合表现,单纯考虑岩体内部某一种尺度缺陷或外部单一因素在冻融循环作用下的变化,不足以客观反映损伤情况。对垂直、平行层理试样开展0、20、40次冻融试验,首先探究了层理砂岩在冻融过程中的损伤发育特征,之后基于?100 mm SHPB试验装置,进行5种弹速下的冲击试验,分析了冻融循环条件下层理砂岩冲击破碎块度分布规律,以冻融损伤累积与破碎块度的相关性为理论依据,以力学性质的冻融劣化为思想建立了层理砂岩的冻融劣化模型,研究结果表明：冻融环境下,两种试样孔隙发育、纵波波速表现出显著差异,平行层理试样相对更容易发生损伤;各级冲击弹速下破碎块度分布与冻融循环次数之间存在正相关、负相关以及波动型3种相关关系;劣化模型基于负相关区域数据和成比例相同区域数据得到的强度、峰值应变计算值与实测值非常接近,基于正相关区域数据得到的强度计算值也与实测值有很好的一致性。     

Comparison of arsenic and heavy metals contamination between existing wetlands and wetlands created by river diversion in the Yellow River estuary,China

Samples were collected at 71 sites in the Yellow River Delta Natural Reserve in December 2010 to represent soil conditions before and after the Yellow River (YR) diversion. The As, Cd, Cu, Pb, Zn, and Ni concentrations were measured to determine metal contamination levels. Results suggest that Cd concentrations were significantly higher after the YR diversion than before. The As, Cd, Cr, Cu, Ni, Pb, and Zn soil contamination indices did not exceed contamination levels, although the heavy metal content increased after the YR diversion. The mean concentrations of these heavy metals were lower than the Class I criteria. Correlation analysis shows significant correlations between As and Cr, Cu, Ni, Pb, and Zn concentrations both before and after the YR diversion. However, no significant correlations were observed between heavy metal concentration and pH before the diversion, and no heavy metal concentration was correlated with salinity. The principal component analysis indicates that these trace elements, including As, were closely correlated with each other and therefore likely originated from shared pollution sources before the diversion. These results are useful for assessing the heavy metal contamination and proposing feasible suggestions to improve soil quality.     

冻融作用对土结构性的影响及其导致的强度变化

冻融作用通过改变土的结构性从而改变土的力学性质.以青藏粉质黏土为研究对象,对一定干密度的饱和重塑试样分别进行封闭和开放状态下的冻融试验.通过土样电阻率的改变来反映冻融作用对土中孔隙的影响;对冻融前后的试样分别进行CT扫描,定量分析土样的损伤程度,来反映土颗粒联结的改变.对冻融前后的土样进行不固结、不排水三轴剪切试验,得到其强度参数,并将冻融作用引起的结构变化与强度参数的变化建立联系.研究表明:对试验中采用的土样,经过冻融作用后电阻率增大,反映到强度参数上,冻融作用导致土的内摩擦角增大;CT扫描定量分析发现,经过冻融之后,密度增大,CT损伤量为负值,反映到强度参数上,冻融后黏聚力增加.因此,强度参数的变化与土颗粒的胶结和重排列,粒径重分配以及孔隙大小比例的变化有关.