四川盆西平原区裸土扬尘中Pb、Cd化学形态的生物有效性

为探究四川盆西平原区裸土扬尘中Pb、Cd总质量分数与其生物有效性的规律,在构建的"阳离子型污染物土壤表层运移行为研究系统"内进行模拟起尘试验,对土壤样品进行Pb、Cd模拟污染试验,结果表明:试验条件下,四川盆西平原区裸土扬尘颗粒物中Pb、Cd的总质量分数随着粒径的减小而增大,其中Pb的化学形态以碳酸盐结合态为主(44....     

吕梁市扬尘重金属含量及环境风险分析

通过采集吕梁市采暖期和非采暖期不同功能区的扬尘样品并测定重金属铜、锌、镍、铅、镉的含量,评价其污染程度。结果表明:吕梁市扬尘中各重金属浓度采暖期非采暖期,Pb、Cd的浓度高于山西土壤元素背景值,采暖期分别超标2.29、29.15倍,非采暖期分别超标1.66、26.08倍。地积累污染指数法结果表明,吕梁市扬尘中重金属元素Cd属于严重污染,Pb属于轻度污染,Cu、Zn、Ni无实际污染。潜在生态风险指数法结果表明:吕梁市扬尘中重金属元素达到了严重污染水平和严重潜在生态危害。     

杨庄采煤沉陷区周边土壤重金属分布特征

为了解采煤沉陷区周边土壤中重金属污染情况,以淮南杨庄采煤沉陷区为例,采集3个煤矸石样品以及沉陷水域周边6个土壤样品,用火焰原子吸收分光光度法测定八种重金属(Cu、Zn、Pb、Ni、Cd、Cr、Fe、Hg)的含量,分析污染情况,结果表明杨庄矿沉陷水域周边土壤中重金属Cu、Cr、Hg达土壤环境质量标准(GB 15618-1995)一级标准,Pb、Ni、Cd达二级标准,Zn达三级标准,Zn、Pb、Cd、Ni超过淮南土壤背景值。相关性分析结果表明不同样品之间存在较强程度相关性,说明杨庄采煤沉陷区周边土壤重金属污染与煤炭开采过程和煤矸石的堆放有关。     

混酸分解-电感耦合等离子体质谱法测定土壤中铬镉铅

本文采用HNO3-HF-HCl O4分解-电感耦合等离子体质谱法(ICP-MS)测定土壤样品中Cr、Cd、Pb,对样品预处理方法,条件等进行了改进和优化,同时给出了方法的检出限、线性范围、精密度、准确度、加标回收率等方法参数。经国家标准土壤样品验证,方法的精密度符合分析要求,结果令人满意。研究表明,该方法适用于土壤样品中Cr、Cd、Pb的分析测定。     

微波消解-ICP法测定土壤中的铅和镉

为探索不同混酸微波消解土壤对重金属的测定影响,建立微波消解-ICP测定土壤中Pb和Cd含量的方法.采用不同混酸进行微波消解土壤样品,并运用ICP-OES测定了重金属(Pb和Cd)含量.结果表明:采用HNO3-HF-HClO4混合酸微波消解土壤样品,测定结果均在标准参考值范围以内,结果令人满意.该方法用于测定土壤中Pb和Cd,处理效果好,准确率高.     

来宾市兴宾区蔗田土壤重金属分析与评价

为分析"中国糖都"来宾市兴宾蔗区土壤重金属污染现状,对来宾市兴宾蔗区蔗田15个表层土壤样品的重金属Cu、Pb、Ni、Cd、Cr的含量进行检测,利用单项污染指数法、内梅罗综合污染指数法、潜在生态危害指数法对土壤重金属污染特征及生态风险进行评价。结果表明,蔗区土壤中Cu、Pb、Ni、Cd、Cr等重金属含量均值分别为3.21、9.57、14.05、0.04、231.01 mg/kg,均未超过《土壤环境质量农用地土壤污染风险管控标准(试行)》(GB15618-2018)所列土壤风险管制值。15个取样点中有9个土壤样本显示受到重金属Cr污染,有1个土壤样本显示受到重金属Cd污染。蔗区土壤重金属综合污染潜在危害程度为轻微生态危害。     

杭州某典型地区重金属的生物放大及生态风险

采用火焰原子吸收法对浙江省杭州市河桥镇(马坞里、下院、岭上)3个区域土壤样品中4种重金属(Cu、Zn、Pb和Cd)含量进行测定。研究表明,土壤中4种重金属含量差异较为显著,不同的农作物之间重金属含量也存在着明显的差异。重金属Cu、Zn、Pb和Cd在大豆农作物中富集效应明显,其富集系数BCF值均大于1,特别是重金属Cd,在大豆作物中富集系数高达2.868~4.069。     

铅镉污染土壤的固化处理研究

模拟Pb、Cd污染土壤,加入自制的固化剂,进行了毒性浸出试验.试验结果表明,加入质量分数为4％的固化剂后,对于铅为2500 mg/kg,镉为50 mg/kg污染土壤,铅的浸出质量浓度是4.47 mg/L,镉的浸出质量浓度是1.05 mg/L,满足固体废物浸出液中危害成分浓度限值要求.浸出液中的Pb、Cd浸出浓度比模拟污...     

层栽红托竹荪重金属污染特征

通过添加不同剂量活性炭改良剂进行红托竹荪层架栽培试验,分析改良剂使用后红托竹荪土壤和竹荪不同组织部位中Pb、Cd、Cr、Hg、As的含量,判断竹荪种植土壤的污染状况和竹荪不同组织部位富集Pb、Cd、Cr、Hg、As能力大小与改良剂之间的关系。结果表明:基质土壤元素含量差异明显分别为Pb:27.48～51.65 mg/kg,Cd:0.28～0.56 mg/kg,Cr:94.37～126.19 mg/kg,Hg:0.05～0.14 mg/kg,As:13.43～22.18 mg/kg,Cr和As的超标现象较严重在土壤中的累积特征显著。研究区基质土壤中Pb、Cd、Cr、Hg、As的Eir和RI均属于轻微水平,潜在风险较小。红托竹荪对Cd的富集能力最强,需要引起重视。     

冶炼厂周围土壤中Cu、Pb、Zn、Cd的形态分布研究

目的：观察冶炼厂周围土壤的重金属分布情况。方法：本研究选取云南鸡街周围荒地土壤为样品,采用消解法对土壤中的Cu、Pb、Zn、Cd进行总量分析,并运用Tessier连续提取的五态方法研究该区土壤中Cu、Pb、Zn、Cd的形态分布特征,来检测该地区的土壤生态。结果：该冶炼厂周围土壤中四种重金属的总浓度高于国家土壤环境质量指标;形态分析发现Cu、Pb、Zn、Cd的主要形态为残渣态,可交换态所占比例最小;四种重金属的生物活性和迁移能力大小均为Cd〉Pb〉Zn〉Cu。结论：（1）该地区土壤被重金属污染。（2）为该地区土壤修复提供理论依据,重金属的提取和回收提供资料。     

重金属螯合剂处理垃圾焚烧飞灰的稳定化技术

引言随着我国社会经济的发展、城市化进程的加快以及人们物质生活的提高,全国城市生活垃圾年产生量已达1.5亿吨以上,并以每年8%～10%的速率增加[1-3]。城市垃圾焚烧是我国垃圾处置的重要手段,在焚烧过程中将产生大量飞灰,飞灰产量与垃圾种类、焚烧条件、焚烧炉型及烟气处理工艺有关,一般约占被焚烧垃圾量的3%～5%。分析表     

Soil quality response to long-term wastewater irrigation in Inceptisols from a semi-arid environment

Thirty-nine paired soil samples belonging to Inceptisols, irrigated with wastewater and well water, were examined to monitor the combination of clay mineralogy, physicochemical properties, and trace metals (Zn, Cu, Cd, and Pb) following long-term wastewater irrigation. Results of XRD analysis indicated that the quantity of clay minerals did not change by long-term wastewater irrigation although some modifications in smectite were occurred in Fluvaquentic Endoaquepts compared to control (well water-irrigated soil). Irrigation with wastewater was resulted in an increase in clay content from 3 to 17%, EC from 90 to 160%, organic carbon from 13 to 44%, and CEC from 10 to 13%. In this context, improvement in total N was as 80–110%, available P as 270–330%, and available K as 5–50% as compared to the control soil. Irrigation with wastewater was led to a significant enrichment in both EDTA-extractable and total metals of Zn, Cu, Cd, Pb, mainly as result of the combination of their addition through wastewater along with interaction between the used wastewater and its receiving soils. In the light of this, wastewater irrigation system showed the relative enrichment (RE) for total-Zn, Cu, Cd, and Pb as 3.6–6.8, 2.8–4.9, 4.4–5.7, and 1.8–2.3, respectively. Fine particle-size fraction (<0.002 mm), organic matter, and calcium carbonates were appeared as the main agents in retaining the total trace metals as reflected in significant positive correlation among the physicochemical properties and the examined metals. Degree of contamination (C_d) for the four analyzed metals was in the range of 3–5. Based on C_d values, the wastewater-irrigated soils were classified as moderate degree of contamination (2 ≤ C_d < 4) to high degree of contamination (4 ≤ C_d < 8). Fluvaquentic Endoaquepts highlighted to be a major contributor of the load and contamination rate of trace metals regarding to geoaccumulation index, contamination factor, and Degree of contamination.     

生物钝化修复镉污染土壤研究进展

回顾了我国含镉土壤的场地修复。综述了利用生物钝化技术修复镉污染土壤的研究现状,重点探讨了微生物的代谢产物与镉产生硫化物或磷酸盐沉淀的微生物沉淀作用、微生物的细胞壁和其分泌的胞外聚合物直接吸附镉的微生物吸附作用以及镉离子透过微生物的细胞膜而被固定在细胞内的微生物摄取作用等生物钝化机理,并对有机钝化过程和无机钝化过程进行了介绍和评价。分析了镉在土壤中的离子交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态和残渣态等赋存形态以及土壤中pH值、氧化还原电位、有机质、共存重金属和微生物等因素对镉的生物可利用度的影响。最后阐述了生物钝化技术的优点以及该技术不能将重金属从土壤中永久去除的问题,指出生物钝化技术与其他修复方法相结合是其未来的发展方向。     

Carbonate-coordinated metal complexes precede the formation of liquid amorphous mineral emulsions of divalent metal carbonates

During the mineralisation of metal carbonates MCO3 (M=Ca, Sr, Ba, Mn, Cd, Pb) liquid-like amorphous intermediates emerge. These intermediates that form via a liquid/liquid phase separation behave like a classical emulsion and are stabilized electrostatically. The occurrence of these intermediates is attributed to the formation of highly hydrated networks whose stability is mainly based on weak interactions and the variability of the metal-containing pre-critical clusters. Their existence and compositional freedom are evidenced by electrospray ionization mass spectrometry (ESI-MS). Liquid intermediates in non-classical crystallisation pathways seem to be more common than assumed.     

The distribution and transformation of iron and manganese in soil fractions in a savanna Alfisol under continuous cultivation

Data on the responses of micronutrients in definable soil fractions to cultivation and management are required to design judicious fertilization practices to improve soil fertility in the savanna. Iron and manganese fractions are particularly sensitive to cultivation and management practices. The objectives of this study were to determine the sizes and changes in Fe and Mn fractions in a savanna Alfisol cultivated for 50 years and fertilized with (i) NPK, (ii) farmyard manure (FYM), (iii) FYM + NPK, (iv) a control plot, and (v) a natural site adjacent to the experimental field. The mean concentration of total Fe (Fe_T) ranged from 9.4 g kg^–1 in the surface layer to 45 g kg^–1 in the subsurface layer, whereas total mangenese (Mn_T) concentration ranged from 79 mg kg^–1 in the surface layer to 279 mg kg^–1 in the subsurface layer. The distribution of Fe_T followed the distribution of clay in the soil profile across the field. The distribution of Mn_T did not, however, follow the characteristic depth distribution of clay as observed for Fe_T, suggesting that Mn movement and distribution in this soil might be independent of clay movement and distribution. The concentrations of DTPA extractable Fe and Mn were much higher than the critical levels delineated for soils. Application of FYM increased the concentration of amorphous oxide bound Fe over the natural site and reduced the concentration of residual or inextractable Fe in the soil. Similarly, fertilization with FYM reduced the concentration of residual Mn, and increased the exchangeable, amorphous oxide bound and reducible Mn compared to the natural site. It seems that sole application of FYM or application in combination with NPK rather than NPK alone can mobilize non-labile Mn and Fe sources into labile and plant available forms of Fe and Mn in a savanna Alfisol.     

Transport processes of hydrated ions at polymer/oxide/metal interfaces: Part 2. Transport on oxide covered iron and zinc surfaces

The study of ion transport processes on non-polymer coated bare oxide covered iron and zinc surfaces showed that the presence of adsorbed ions determines the ion distribution on oxide/metal surfaces in humid atmosphere. For fundamental studies of ion ingress at polymer/oxide/metal interfaces, already the transport analysis in the absence of the polymer reveals important mechanistic aspects. Sophisticated spectroscopic techniques were applied for the correlation of electrochemical data with local surface chemistry. In-situ Scanning Kelvin Probe (SKP) measurements of the local interfacial potentials of oxide covered iron and zinc substrates and ex situ time-of-flight secondary ion mass spectroscopy (ToF-SIMS) analysis showed that the surface layer charge influences the ion transport processes. A model is proposed to explain the basic mechanism of hydrated ion transport on oxide covered zinc and iron.     

扬州古运河三湾段沉积物中重金属潜在生态风险评价及形态变化特征

扬州古运河是京杭大运河最古老的一段,为了解沉积物中重金属污染状况,采用Hakanson潜在生态风险评价扬州古运河三湾段沉积物中重金属Cr、Ni、Cu、Zn、Cd和Pb的风险水平,并对形态分布特征进行了研究。结果表明:扬州古运河六种重金属的含量均高于背景值,其中Cd含量为其背景值的13.15倍。沉积物中重金属的累积潜在生态风险指数RI高达456.55,沉积物的总体潜在生态风险等级为强。沉积物中Pb的主要赋存形态主要以铁锰氧化态存在,而Zn和Cd主要以酸可溶态形式存在,说明这三种重金属的潜在生态风险水平较高。     

人工湿地-灯心草处理系统对高浓度重金属污水的净化效果研究

以搭建垂直流人工湿地系统并种植湿地植物(灯芯草)为研究对象,研究人工湿地基质以及湿地植物对重金属Cd、Pb的富集特性,分析了重金属在植物体和土壤中的动态分布,以评价灯芯草对重金属Cd、Pb的综合富集能力以及人工湿地系统对复合重金属污水的净化效果,为利用植物修复金属污染土壤提供理论依据和技术支持。结果显示,湿地植物(灯芯草)对复合重金属Cd、Pb的富集特性高于湿地基质的富集特性。此外湿地植物(灯芯草)的根、茎、叶对重金属Cd、Pb的富集能力也各有不同,其中灯芯草根部对重金属Cd、Pb的富集效果明显大于茎、叶。对于湿地基质,其表层、中层、下层对重金属Cd、Pb的富集效果也有所差异,其表层基质对重金属Cd、Pb的富集效果明显大于中层、下层。湿地土壤基质及湿地植物(灯芯草)对复合重金属Cd、Pb污染的净化有一定作用,其中以湿地植物(灯芯草)根部及湿地表层基质净化效果较为最佳,对污水中Cd、Pb的去除率分别达到69.5%及72.3%,净化效果较好。