Application of ultrasonic to speciation analysis of heavy metals in soil

In order to reduce the operation time and improve the extraction efficiency, ultrasonic energy by means of ultrasonic bath was used to the modified Tessier sequential extraction for speciation analysis of heavy metals in soil. Extractable contents of Cu, Fe, Mn, Ni, Pb and Zn were measured by atomic absorption spectroscopy(AAS). The merit of the ultrasonic extraction(UE) applied to the modified Tessier method is not only that the operation time for the first 4 fractions was reduced from ca.18 h to 8 h, comparing with conventional extraction(CE), but also the extraction efficiency was higher. The results for both of UE and CE were consistent. The extractable Cu, Ni and Zn in the sample No.1 were mainly associated with the third fraction(Fe-Mn oxides fraction), and fourth fraction(organic matter fraction) in the sample No.2. The extractable Fe and Mn were all mainly associated with the third fraction, and Pb the fourth fraction in both of the samples. The effects of concentration of hydroxylamine chloride on the capability for the extraction of studied metals were also studied.

Applied research of correspondence analysis method in waste tailings reservoir heavy metal pollution monitoring points optimization

In order to optimize monitoring points and monitoring factor, the relationshipbetween pollutants and soil sample were established by correspondence analysis.Thestudy results show that the reflecting monitoring points and monitoring factors in thegraphic on the same factor axis can clearly express the intrinsic link between pollutantsand monitoring points and distribution characteristics.To determine the main monitoringpoint and the main monitoring indicators can reduce and optimize the number of monitoringpoints under the premise of ensuring the typical and representative of monitoring data.Using the correlation of pollutants can reduce the number of monitoring indicators and improvethe effectiveness of data collection.

Study of heavy metal speciation in branch sediments of Poyang Lake

This study concentrates on the environmental pollution level of sediments in the six branches of Poyang Lake, the biggest fresh water lake in China. This is the first systematic report on the speciation analysis of heavy metals （Cu, Co, Cd, Pb, and Ni） in the six branches of the lake. A reported analytical procedure involving a five-step sequential extraction is used for the partition of particulating heavy metals. The sediment samples are analyzed using flame atomic absorption spectroscopy （FAAS）. Experimental results obtained from five replicate samples of fluvial bottom surface sediments at the sampling points demonstrated that the relative standard deviation of the sequential extraction procedure was generally better than 10% （Cd except）. The average extracted contents of the five elements, analyzed after all five steps, are found to be （mg/kg） for Cu： 26.89, Co： 16.25, Cd： 1.08, Pb： 37.98, and Ni： 20.46. The content of the exchangeable species was generally lower. Except Cu, the percentage of the species bond to organic matter was lower than 20%. The fractions containing the most metal for Cu, Co, and Ni were the residues （52.26%, 45.28%, and 74.82%, respectively）.

Application of chemometrics methods for the estimation of heavy metals contamination in river sediments

The concentration and speciation of six heavy metals in sediments of eight sampling sites of Haihe River were investigated. The metals, namely Cd, Cu, Co, Ni, Mn and Pb were considered. By using sequential extraction(SE), the total metals were divided into five fractions: exchangeable, carbonate bound, iron/manganese oxide bound, sulfides and organic matter fraction and residual fraction. A multivariate statistical approach(principal component analysis, PCA) was used to evaluate the contamination of heavy metals by the total levels and chemical forms, respectively. The results showed that the total metals concentration(TMC) could not provide sufficient and accurate information because the mobility, bioavailability and toxicity of metals depend not only on their total concentration but also on the physicochemical form in which they occur.

Source analysis and risk evaluation of heavy metal in the river sediment of polymetallic mining area:Taking the Tonglüshan skarn type Cu-Fe-Au deposit as an example,Hubei section of the Yangtze River Basin,China

In this paper,25 sampling points of overlying deposits in Tonglushan mining area,Daye City,Hubei Province,China were tested for heavy metal content to explore pollution characteristics,pollution sources and ecological risks of heavy metals in sediments.A geo-accumulation index method was used to evaluate the degree of heavy metal pollution in the sediment.The mean sediment quality guideline quotient was used for evaluating the ecological risk level of heavy metal in the sediment.And a method of correlation analysis,clustering analysis,and principal component analysis was used for preliminary analysis on the source of heavy metal in the sediment.It was indicated that there was extremely heavy metal pollution in the sediment,among which Cd was extremely polluted,Cu strongly contaminated,Zn,As,and Hg moderately contaminated,and Pb,Cr,and Ni were slightly contaminated.It was also indicated by the mean sediment quality guideline-quotient result that there was a high ecological risk of heavy metals in the sediment,and 64%of the sample sites had extremely high hidden biotoxic effects.For distribution,the contamination of branches was worse than that of the main channel of Daye Dagang,and the deposition of each heavy metal was mainly influenced by the distance from this sample site to the sewage draining exit of a tailings pond.The source analysis showed that the heavy metals in the sediment come from pollution discharging of mining and beneficiation companies,tailings ponds,smelting companies,and transport vehicles.In the study area,due to the influence of heavy metal discharging from these sources,the ecotoxicity of heavy metals in the sediment was extremely high,and Cd was the most toxic pollutant.The research figured out the key restoration area and elements for ecological restoration in the sediment of the Tonglüshan mining area,which could be referenced by monitoring and governance of heavy metal pollution in the sediment of the polymetallic mining area.

Heavy Metals Concentration and Speciation in Arid Zone Rivers （Amudarya and Syrdarya） of Central Asia

The arid zone rivers Amudarya and Syrdarya are located in Central Asia and are subjected to the influx of different kinds of natural and anthropogenic pollutants. The concentrations and speciation of heavy metals, namely, Hg, Cr, Cd, Co, U, Zn, Sc, Fe, Br, Au, and Sm. in the Amudarya and Syrdarya rivers water in the territory of Uzbekistan were investigated by applying the neutron-activation analysis and through experimental modeling using appropriate radionuclides. The heavy metals speciation in the rivers water was separated in cationic, anionic, and a combination of colloidal and neutral forms. The experimental results showed that heavy metals in the Amudarya and Syrdarya rivers water migrate as a complex set of suspended solids, cationic, anionic, and a combination of colloidal neutral forms. The ratio of neutral and colloidal forms averages approximately 40% for the majority of the investigated heavy metals, and the share of neutral and colloidal forms of heavy metals in the Syrdarya river water is slightly less than in the Amudarya river water （10-20%）, which might be due to discharge of water from agricultural and industry sectors into the river.

TiO2 nanoparticles in aquatic environments:impact on heavy metals distribution in sediments and overlying water

The extensive application of TiO_(2)nanoparticles(NPs)highlights the importance of investigating their influence on aquatic systems.In this work,the effect of TiO_(2)NPs on heavy metals speciation was studied on a lab scale.For this goal,a series of aquaria containing water,sediment,and TiO_(2)NPs with various concentrations were set up.The study results revealed that TiO_(2)NPs caused(copper)Cu,(mercury)Hg,(titanium)Ti,and(zinc)Zn to be adsorbed by sediments in the forms of exchangeable and Fe-Mn species.According to measurements,30μg/L of TiO_(2)NPs made Cu,Hg,Ti and Zn concentration in the water column decreased from 33,1.14,20,and 32 to 4,0.58,3,and 22.3μg/L,respectively.Manganese(Mn)was also adsorbed by sediment,and in all experiments,its concentration in the water column reduced from 44 to about 20μg/L.Due to the photocatalytic capacity of TiO_(2)NPs,arsenic(As)concentration in the water column increased from 0 to 8.7μg/L with the introduction of30μg/L of TiO_(2)NPs.The sequential extraction results showed that in all experiments,concentrations of lead(Pb),nickel(Ni),and cobalt(Co)remained constant in different chemical species of sediment,which meant conservative behavior of them in presence of TiO_(2)NPs.In addition,a remarkable change was observed in water quality parameters such as ORP,TDS,TOC,BOD,NO3’and PO_(4)after the introduction of TiO_(2)NPs to aquaria.The reason behind these changes could be related to the decomposition of sediment organic content by TiO_(2)NPs.

Physico-Chemical Characterization and Speciation of Sulphur of Nigerian Coal Samples

Studies of physico-chemical characterization, and chemical speciation of sulphur of seven Nigerian coal samples have been undertaken. The seven coal samples originated from South-east, North-central and North-east of Nigeria where there are proven economic deposits of this mineral. Moisture content, bulk density, percentage ash and loss of mass on ignition of all the coal samples were determined. The ultimate analysis of the raw coal, the corresponding coal ash as well as sulphur content of all samples were carried out with the aid of X-ray fluorescence technique (XRF). The major elements were Fe, Ca and S while the minor metals were K, Sc, Zn, Ni, Ti and Zr. Other metals including Ga, Cu, Mn, Cr and V were found in traces. The Nickel/Vanadium ratio which is a means of providing information on the source rock depositional environment ranged between 8.8 - 32.9. Three different source rock depositional environments were deduced for the coals from their nickel/vanadium ratios, while the calculated values of V/(V+Ni) suggested that they were all formed under oxic condition. The three chemical species of sulphur, sulphate, pyritic and organic sulphur in the seven coal samples were determined using the ASTM method.

Determination of Harmful Elements and Analysis of Pollution Level in Lysimachia christinae

[Objectives]To detect content of Pb,Cd,Hg,As,Cu,Zn,and Cr in Lysimachia christinae,and to analyze the pollution level.[Methods]Seven kinds of elements in L.christinae were determined by Inductively coupled plasma mass spectrometry and analyzed by single index and comprehensive index.[Results]The seven heavy metal elements showed good linearity in their respective concentration ranges.The recoveries of the samples were 84.5%-109.5%,and the RSD values were 2.30%-5.10%.Comparing the measured results of heavy metal elements with the limit values stipulated in the 2020 edition of the Chinese Pharmacopoeia and other standards,the Cr element in 19 batches of samples exceeded the standard,and the Zn element in 7 batches of samples exceeded the standard.The exceeding rates were 100.0%and 36.8%,respectively;the content of other heavy metal elements did not exceed the standard.The order of individual index from large to small was Cr,Zn,Cd,Hg,Cu,As,and Pb,and the average comprehensive pollution level was mild pollution and above.[Conclusions]L.christinae was mainly polluted by Cr,followed by Zn;this study can provide basic data for drafting of the limit standard for heavy metal elements in L.christinae.

骆马湖流域表层沉积物重金属分布特征及风险评价

对骆马湖流域表层沉积物中的重金属分布特征及潜在生态风险进行评估,分析了枯水期、平水期和丰水期3个时段内10种重金属元素(铬、镍、铜、镉、铅、锑、砷、汞、铍、铊)的浓度水平、空间分布和来源。采用潜在生态风险指数法对沉积物中的重金属风险进行了评估。结果显示,镍、铜、镉、铅在部分水期平均浓度高于江苏土壤环境背景值,汞和铊无点位超过背景值,且与其他水体相比,骆马湖流域沉积物重金属污染整体处在中低水平。沉积物中重金属除镉外整体单项生态风险较低,各点位综合潜在风险水平属于中等及以下范畴。相关性分析和主成分分析揭示了重金属污染主要源自工业和农业。

Sequential Speciation Analysis of Heavy Metals in Drinking Water Pipe Scales by Mass Spectrometry

An electrochemical mass spectrometry technique was developed based on a homemade analytical device for sequential analysis of the heavy metals with various speciations in the scales.Four speciations(e.g.,water-soluble speciation,organic speciation,indissoluble speciation and elemental speciation)of heavy metals are sequentially extracted by H_(2)O,CH_(3)OH,EDTA-2Na and electrolysis for online electrospray ionization mass spectrometry(ESI-MS)detection.The method takes significant advantages,such as requiring no tedious offline sample pretreatment,high speed of analysis(20 min),high throughput(multi-metals),good sensitivity(0.5µg/L)and rich chemical information(four speciations).As a result,the rapid comprehensive characterization of four speciations of Pb,Ni,Cu,Zn,Fe,Ba,Mn,Cr and Ca in water pipe scales has been qualitatively achieved.It demonstrated that the present method is a powerful tool for the effective assessment of potential hazards in drinking water,which provides a new analytical idea for evaluating water quality.

复合稳定剂对污泥中重金属的稳定化效能研究

重金属赋存是制约污泥资源化利用的重要因素。选取碳酸钙(CaCO3)、羟基磷灰石(HAP)和海泡石(Sepiolite)3种稳定剂,以污泥干重的2%、5%、10%投加到供试污泥中,21 d后,采用四分法取样分析浸出毒性及重金属形态,结果表明:3种稳定剂对Cd的稳定作用较弱;另外,HAP的投入量与As的稳定效果成反比。将3种稳定剂按比例复配后,以同样方法研究各组配比对污泥重金属稳定效果,结果表明:HAP∶sepiolite∶CaCO3(质量比)为1∶1∶1时效果最好;此时,污泥中Cd的稳定率达到了80%以上,As、Cr、Pb及Cu的浸出稳定率接近100%,只有Zn和Ni的稳定率与单一稳定剂时相比无明显变化;Cd、Cr、Pb及Cu的稳定态较之前单一稳定剂作用无明显变化甚至减少,但复合稳定剂可提高残渣态的比例;As、Zn和Ni的形态则未有明显变化;复合稳定剂间的协同作用,促使Cd、Cr、Pb及Cu的形态向更稳定态转化。

金属组学方法识别水中络合态重金属形态及其吸附净化技术研究进展

Cu^(2+)、Pb^(2+)和Ni^(2+)等重金属离子可与水中乙二胺四乙酸、柠檬酸、酒石酸等有机分子形成络合态重金属。相比于游离态离子,络合态重金属具有更高的水溶性和环境毒性,在广泛的pH值范围内稳定存在且形态复杂,难以通过化学沉淀等常规方法高效去除。对近年来基于金属组学方法的水中络合态重金属复杂形态分析方法进行总结,对吸附净化技术在络合态重金属废水处理中的研究进展进行综述,并对上述领域需要解决的问题进行了探讨和展望。

土壤和沉积物重金属形态分析研究进展

人类社会的发展进程导致土壤和沉积物中的重金属含量远远超过背景值,具有严重的潜在威胁隐患。然而,由于重金属的流动性、毒性以及生物累积性会对环境造成深远影响,重金属形态分析已然成为环境研究的重要一环。目前最具代表性的形态提取方法为Tessier法和BCR三步法,为标准物质研制、重金属污染评估、生态修复以及生物有效性风险等问题提供了有效解决方案,但也有着各自的局限性。总结目前常用的元素形态提取分析方法,系统对比论证,讨论重金属形态分析方法未来可能出现的问题和发展方向,以期为土壤及沉积物重金属污染研究提供思路与支撑。

土壤中重金属形态及有机物组分的电化学-质谱分析

本研究建立了一种电化学-质谱(EC-MS)法高通量分析土壤样品中的金属组分和有机物。首先,根据理化性质,将土壤样品中的金属组分和有机物组分分为水溶态、脂溶态、难溶态和可氧化态等4种形态;然后,分别采用萃取、反应、电解等方式对4种形态组分进行在线顺次提取;将提取后的组分在线传输至电喷雾电离源进行离子化,随后进行正、负离子模式检测。实际样品分析结果表明,该方法成功检测出土壤样品中多种水溶态金属盐和有机物(如Mg、Cr、Ni、Zn、Co、Cu、Al、Pb等多种水溶性金属盐,尿素及多种有机胺)、20多种脂溶态有机羧酸、以及难溶态金属盐(Mg、Ni、Cr、Pb、Co)和可氧化态(Cu、Pb)。该方法可为环境评估和环境治理提供技术支持。

基于文献计量的重金属污染对中药材影响的研究进展分析

中药材是重要的经济植物,其产品品质一直备受人们关注。影响其品质的因素众多,重金属污染作为重要影响因素之一,会使其品质下降。探讨重金属污染对中药材影响的研究进展、热点及发展趋势,为进一步了解重金属污染对中药材影响提供依据。结合文献计量学法,通过Web of Science(WOS)核心合集数据库和中国知网(CNKI)下载的1994—2023年重金属污染对中药材影响的相关文献作为研究对象,利用CiteSpace和VOS viewer可视化分析软件,从不同角度对重金属污染影响中药材相关领域进行可视化分析。结果表明,1994—2023年有关重金属污染对中药材影响方面研究的发文量总体呈上升趋势,2022年的发文量最多,为491篇;中文文献相较于英文文献的发文量少;中国、美国和日本3国的发文量排世界的前3位;北京中医药大学发文290篇,在该研究领域的研究机构中占主要地位。该领域共有368种来源出版物,药材、农药残留、土壤、重金属及修复等是该领域的重点研究对象。在重金属污染对中药材影响的研究领域中,中药材和污染物受到较大的重视,是目前的研究前沿,植物药滇重楼值得继续关注。

高炉矿渣与磷酸盐复配材料对Cu、Pb、Zn污染土壤的钝化效果研究

选取湖北某矿区重金属污染土壤,通过钝化实验和金属赋存形态分析实验探究了经高炉矿渣(BFS)及其与磷酸二氢钾(MKP)的复配材料修复前后重金属Cu、Pb、Zn的浸出毒性及赋存形态的变化情况。结果表明,BFS-MKP复配材料对土壤的钝化效果优于BFS单独处理,BFS-MKP复配材料对土壤中Cu、Pb的钝化效果要优于Zn,针对Cu、Pb的钝化效率最高分别达到86.1%与88.2%。此外,BFS-MKP复配材料可以促进土壤中活性较高形态的Cu、Pb向较稳定的形态转化。添加复配材料并养护28 d后,土壤中可交换态Cu、Pb含量占比可分别从16.6%、22.7%最低降至0.6%、4.3%,而残渣态Cu、Pb含量占比可分别从64.3%、41.7%最高升至89.3%、81.9%。

云南省农田表土重金属分布特征与污染评价

为了解云南省农田表土中重金属含量的分布特征和污染情况,在全省范围内农田设立了113个具有代表性的表土采样点,测定了样品中Cu、Pb、Cr、Zn含量。采用单因子指数法、内梅罗综合污染指数法、地统计学分析及Pearson相关性分析对表土重金属污染进行了评价,结果表明:Cu、Pb、Cr、Zn四种重金属含量均值分别是云南省背景值的1.87、1.52、1.92、1.39倍;Cu、Cr、Zn含量的空间分布大体呈东高西低,Pb含量呈从西南到东北逐渐降低的趋势,综合污染指数分布与重金属含量分布较为一致;相关性分析中Pb、Zn与有机质呈显著正相关,Cu、Cr与砂粒呈正相关。Cu、Cr、Zn在空间分布和相关性分析中均显示其有相似的来源,推测为有机肥料。整体上,云南省农田污染属于轻微污染。

复杂网络在土壤重金属含量关联分析中的应用

土壤重金属污染是当今社会最为关注的环境问题,对土壤不同重金属含量变化的关联性研究可以为土壤重金属治理提供理论依据。本文构建了一个复杂网络模型来分析土壤中重金属含量的关联性。通过采集实验基地7个区域的210组环境重金属数据,构建同现矩阵和复杂网络模型来分析该实验基地重金属的关联性。实验的结果显示,应用本文的方法,可以较好地描述不同重金属之间变化的潜在联系。