碘化钾-甲基异丁基甲酮萃取-火焰原子吸收分光光度法连续测定地球化学样品中痕量银镉铊     

肖凡  徐崇颖  邢刚  付爱瑞 《岩矿测试》2007,26(1):67-70

研究了碘化钾-甲基异丁基甲酮（KI—MIBK）萃取-火焰原子吸收分光光度法连续测定地球化学样品中痕量银、镉和铊的主要条件。通过对火焰原子吸收分光光度计气路控制系统及雾化器的改进，较大地改善了萃取-火焰原子吸收分光光度法测定银、镉和铊的稳定性和灵敏度。选择萃取酸度为1．2mol／L HCl、水相和有机相体积配比为3：1～4：1，方法精密度（RSD，n=12）为Ag4．5％～9．6％、Cd1．5％～7．9％、T14．5％～5．4％，检出限（3s）为Ag0．004μg/g、Cd0．007μg／g、T10．011μg/g，符合多目标地球化学调查样品测试及质量监控要求。用国家一级标准物质和密码组合标准物质进行验证，测试结果令人满意。  相似文献   

天津城郊污染区土壤Cd的赋存形态及其对蔬菜的影响     

张久潮  曹淑萍 《地质通报》2007,26(11):1494-1498

介绍了天津城郊污染区土壤Cd元素的赋存形态,探讨了Cd的赋存形态对蔬菜的影响。研究区土壤中Cd的污染程度高,以蔬菜种植为主,水溶态、离子交换态和碳酸盐态这几种容易(或在一定条件下容易)被作物吸收的Cd含量占65.2%;而有机态结合态、铁锰氧化物结合态和残渣态等难被作物吸收的Cd含量低,仅占23.3%。污染区大白菜、芹菜和油麦菜3种蔬菜中的Cd与土壤中Cd的全量、Cd的多种形态都呈较明显的正相关。油菜、芹菜和油麦菜样品存在超标现象。  相似文献   

土壤Cd污染对甘蓝光学显微成像特征的影响     

牟永明  陈明冯流郭行  曹晓娟 《地质通报》2007,26(11):1503-1508

在不同浓度CdNO_3的土壤中栽培甘蓝,应用光学相干层析成像系统(OCT)对甘蓝不同生长时期的叶片进行检测。结果显示:土壤中Cd含量较低时OCT值有降低的趋势,表明Cd对甘蓝植物的种子萌友与生长有一定的促进作用;而Cd浓度高于100mg/kg时,OCT值持续升高,表明Cd对甘蓝植物的种子萌发与生长均起到强烈的抑制作用,并且后期的累积作用对甘蓝叶片组织造成一定的损害。  相似文献   

Determination of nitrate in seawater: Nitrate to nitrite reduction with copper-cadmium alloy     

D.J. Hydes  N.C. Hill 《Estuarine, Coastal and Shelf Science》1985,21(1):127-130

Determination of nitrate in seawater first requires its reduction to nitrite. Construction of a reductor column for use during continuous flow analysis at sea is described. Novel use is made of an alloy of cadmium and copper ($\text{50}\text{50}\text{w}\text{w}$) crushed to between 500 and 350 μm. Its performance is similar to that of the cadmium wire type of reductor but offers advantages of easier preparation and control of reductor volume.  相似文献   

母岩类型对土壤和沉积物镉背景的控制: 以贵州为例     

夏学齐  季峻峰  杨忠芳  卢新哲  黄春雷  魏迎春  徐常艳  梁卓颖 《地学前缘》2022,29(4):438-447

镉是土壤和沉积物中最受关注的重金属污染物之一,合理确定其自然背景对于环境管理具有重要意义。然而,由于不同基岩中该元素含量差异很大,且在风化成壤过程中元素也可能发生富集或贫化,造成该元素具有很大的空间变异,甚至可以超出筛选值和管制值。本文从基岩-土壤地球化学元素迁移规律出发,以基岩类型较复杂、镉空间变异较大的贵州省为例,基于土壤和沉积物调查数据,建立基岩与土壤或沉积物中镉含量的对应关系,筛选合理的岩性类型端员和背景区域划分方法,为环境管理确定基础背景。研究结果显示,岩性类型是造成土壤镉空间变异的重要因素,石灰岩(排除白云岩)、玄武岩、辉绿岩和碳质页岩等是造成土壤高镉背景的重要岩石类型。相对母岩类型,岩石所在地层时代对土壤镉背景的影响不太明显。本文通过大量数据统计,给出了相对较纯的岩性发育土壤的镉背景值和变异区间,不纯岩性或地质单元发育土壤的镉背景值可能受多个岩性端员的影响。  相似文献   

等离子质谱法测量土壤中铅、镉、铬的消解方法比对     

邢飞 《吉林地质》2015,(2)

通过高压罐密闭消解、微波消解与聚四氟乙烯坩埚常压消解,等离子质谱法测量土壤中重金属铅、镉、铬,结果表明三种方法均满足土壤质量评价要求,其中聚四氟乙烯坩埚常压消解除铬元素系统稍偏低。聚四氟乙烯坩埚常压消解具有简单,快速,稳定,方法线性范围为(0~200)ng/m L,相关系数均在0.999以上,铅、镉、铬检出限分别是0.7,0.03,3 ng/m L,能满足农业土壤重金属测量要求。  相似文献   

Trace metal fronts in Scottish coastal waters     

P. W. Balls 《Estuarine, Coastal and Shelf Science》1985,20(6):717-728

Dissolved cadmium and copper concentrations have been determined in 76 surface water samples in coastal and ocean waters around Scotland by anodic stripping voltammetry (ASV). A trace metal/salinity ‘front’ is observed to the west, north and north-east of Scotland separating high salinity ocean water (>35 × 10⁻³) with low concentrations of dissolved Cd and Cu from lower salinity (<35 × 10⁻³) coastal water containing higher concentrations of Cd and Cu. Mean Cd concentrations in ocean and coastal waters are 7 ng dm⁻³ (0·06 n ) and 11 ng dm⁻³ (0·10 n ) respectively; for Cu the respective levels are 60 ng dm⁻³ (0·95 n ) and 170 ng dm⁻³ (2·68 n ). The observed distribution is attributed principally to freshwater runoff and the advection of contaminated Irish Sea water into the study area.  相似文献   

Mobility of arsenic and environmentally significant elements in mine tailings following liming     

T. L. Noble  B. G. Lottermoser  A. T. Townsend 《Australian Journal of Earth Sciences》2016,63(6):781-793

Remediation of a legacy tin-tailings site in northeast Tasmania, Australia was carried out by statutory authorities. This study evaluated the fate of As and other deleterious trace metals Cd, Cu, Fe and Zn (among others) following the application of lime and fertiliser. Arsenic concentrations in the tailings ranged from 86 mg/kg to 0.26 wt%. Surface application of lime resulted in a 100-fold reduction in dissolved As concentrations in on-site surface waters; from an average of 196 µg/L prior to lime addition, to between 2.0 and 7.4 µg/L post-amendment. The concentration of other deleterious elements, however, varied between dry and wet cycles. The concentrations of Cd, Cu and Zn in surface waters were high and similar to pre-remediation levels during dry conditions (0.4, 13.5 and 6.1 mg/L, respectively), and only below freshwater ecosystem protection values during wet conditions. Bioaccumulation of Cd was observed in the naturally occurring coloniser, Juncus pallidus, with 4–5 times more Cd in the above-ground biomass relative to the tailings. Ferric arsenate (scorodite) was the dominant source of As identified in the tailings mineralogy. Hydrous ferric oxides and Fe-bearing cassiterite were also identified as hosting As. The pH increase in the surface lime-amended tailings was inferred to result in precipitation of observed hydrous ferric oxides, hematite and goethite, providing high-surface area for adsorption of arsenate onto positively charged surfaces. Jarosite was observed in both the surface lime-amended and subsurface non-amended tailings and suggests a continued supply of acidity to the pore waters despite the application of lime. Leaching experiments showed that As was more mobile in the lime-dosed tailings than in subsurface non-amended tailings, likely owing to desorption in alkaline pH conditions. By contrast, the mobility of Cd, Cu and Zn in the surface lime-amended tailings was reduced by at least two orders of magnitude compared with subsurface non-amended tailings. Evaluation of the applied rehabilitation strategy highlights the limits of a single chemical remediation approach to a polymetallic (including metalloids) waste with complex mineralogy and large seasonal fluctuations. Rehabilitation of metalliferous mine sites requires a complete understanding of all environmentally significant elements and their pathways into local receptors.  相似文献   

Heavy Metal Concentrations in Rice from Guangzhou and Associated Health Risks   总被引：1，自引：1，他引：0  

CHEN Nengchang  ZHANG Xiaoxia  ZHENG Yuji 《资源与生态学报(英文版)》2018,9(1):85-91

In recent years, excessive levels of cadmium (Cd) in rice have been a focus of attention of the government, the public and scientists. In Guangzhou rice is a staple food for most citizens and understanding the level of Cd and other heavy metals in rice is important for food safety and health. Consumers in different income groups purchase rice from various sources at different prices but we know little about the relationship between price and safety. At the same time, the presence of zinc (Zn) can also affect the level of risk from Cd in rice and so affect food safety. This study offers a preliminary exploration of interactions between price, safety and nutritional quality. 125 rice samples were collected from markets and from the homes of high-income, middle-income and low-income groups in Guangzhou city, and were tested for the content of Cd and Zn. The results showed that 25.6% of the rice samples contained Cd in excess of the national standard, with higher levels of Cd in Indica rice than in Japonica. At the same time, we designed a questionnaire survey for groups with different incomes to assess their exposure to risks from rice with Cd and their perceptions and sources of information about risks. The survey showed that, as a whole, the low-income group faces higher risks from rice with Cd, and that there is strong public demand for scientific information about Cd in rice.  相似文献   

基于鳃的microRNA转录组研究中国蛤蜊对重金属镉的响应     

张晶晶  李宏俊  秦艳杰  刘敏  叶晟 《海洋学报》2016,38(12):118-131

中国蛤蜊（Mactra chinensis）是一种重要的经济贝类,分布于我国的辽宁和山东。近年来,生境恶化和过度捕捞导致我国蛤蜊资源量减少。我们利用Illumina Hiseq-2500平台对中国蛤蜊鳃的microRNA转录组进行测序,运用差异表达寻找对镉刺激有响应的功能microRNA。结果显示对照组获得了14 415 256条clean reads,实验组获得了15 570 111条clean reads。在这些reads中一共存在14 584 077小RNA,包括1 898 035条unique小RNA,其中对照组和实验组共有187 859条unique小RNA。两个组的小RNA文库的片段长度分布是相似的,大部分小RNA长度分布在26~27 nt。在对照组文库中最丰富的片段长度是27 nt,其次是28 nt、26 nt和23 nt。在实验组文库中,数量最丰富的片段长度是26 nt,其次是27 nt、28 nt和23 nt。经过对序列前体以及结构特征的分析,发现这两个组中一共有50个microRNA,其中已知的是38个,新发现的是12个。对照组和实验组microRNA含量最丰富的片段长度是23 nt。通过差异表达分析,5个microRNA基因具有显著性差异且从对照组到实验组的表达量是上调的,其余45个没有显著性的差异。把这50个序列与中国蛤蜊转录组进行比对,一共找到了542个靶基因。5个具有表达差异的基因一共比对到11个靶基因。把这11个靶基因与NCBI数据库比对,4个靶基因在COG中得到注释,1个靶基因在GO中得到注释,6个靶基因在KEGG中得到注释,11个靶基因在nr数据库中得到注释,注释到的基因有泛素蛋白连接酶E3,Wnt信号通路,G蛋白信号调控等。  相似文献