超积累植物富集机制研究方法进展

按照重金属由土壤到根经茎,最后转移至叶细胞的运输流程,概述了超积累植物对重金属离子的富集机制,详细描述了各步骤中重金属离子含量和形态分析方法,重点分析了微质子激发X荧光、扩展X-射线吸收精细结构(extended X-ray absorption fine structure,EXAFS)、X-射线吸收近边缘结构等分析手段在植物不同部位重金属离子含量和形态分析中的应用。     

Comparison of sediment pollution in the rivers of the Hungarian Upper Tisza Region using non-destructive analytical techniques

The rivers in the Hungarian Upper Tisza Region are frequently polluted mainly due to mining activities in the catchment area. At the beginning of 2000, two major mining accidents occurred in the Romanian part of the catchment area due to the failure of a tailings dam releasing huge amounts of cyanide and heavy metals to the rivers. Surface sediment as well as water samples were collected at six sites in the years 2000–2003, from the northeast-Hungarian section of the Tisza, Szamos and Túr rivers. The sediment pollution of the rivers was compared based on measurements of bulk material and selected single particles, in order to relate the observed compositions and chemical states of metals to the possible sources and weathering of pollution. Non-destructive X-ray analytical methods were applied in order to obtain different kinds of information from the same samples or particles. In order to identify the pollution sources, their magnitude and fate, complementary analyses were carried out. Heterogeneous particulate samples were analyzed from a large geographical territory and a 4-year time period. Individual particles were analyzed only from the “hot” samples that showed elevated concentrations of heavy metals. Particles that were classified as anthropogenic were finally analyzed to identify trace concentrations and chemical states of heavy metals.     

Chemometric investigations on the differentiated evaluation of element trace analysis in river waters

The combination of sequential leaching methods for a first assessment of the kind of species in river sediments with multivariate-statistical methods (like factor analysis) for identifying anthropogenic and/or geogenic loading is useful for the differentiated characterization of the pollution state of a river. Electrochemical investigations, planned on the basis of statistical design and following empirical modelling, enables quantitative conclusions on the binding forms of heavy metals in river waters. Deposition-remobilisation effects of heavy metals in the complex system river water-river sediment can be described by PLS modelling.     

Speciation of copper and zinc in size-fractionated atmospheric particulate matter using total reflection mode X-ray absorption near-edge structure spectrometry

The health effects of aerosol depend on the size distribution and the chemical composition of the particles. Heavy metals of anthropogenic origin are bound to the fine aerosol fraction (PM_2.5). The composition and speciation of aerosol particles can be variable in time, due to the time-dependence of anthropogenic sources as well as meteorological conditions. Synchrotron-radiation total reflection X-ray fluorescence (SR-TXRF) provides very high sensitivity for characterization of atmospheric particulate matter. X-ray absorption near-edge structure (XANES) spectrometry in conjunction with TXRF detection can deliver speciation information on heavy metals in aerosol particles collected directly on the reflector surface. The suitability of TXRF-XANES for copper and zinc speciation in size-fractionated atmospheric particulate matter from a short sampling period is presented. For high size resolution analysis, atmospheric aerosol particles were collected at different urban and rural locations using a 7-stage May cascade impactor having adapted for sampling on Si wafers. The thin stripe geometry formed by the particulate matter deposited on the May-impactor plates is ideally suited to SR-TXRF. Capabilities of the combination of the May-impactor sampling and TXRF-XANES measurements at HASYLAB Beamline L to Cu and Zn speciation in size-fractionated atmospheric particulate matter are demonstrated. Information on Cu and Zn speciation could be performed for elemental concentrations as low as 140 pg/m³. The Cu and Zn speciation in the different size fraction was found to be very distinctive for samples of different origin. Zn and Cu chemical state typical for soils was detected only in the largest particles studied (2–4 μm fraction). The fine particles, however, contained the metals of interest in the sulfate and nitrate forms.     

X-Ray analysis of riverbank sediment of the Tisza (Hungary): identification of particles from a mine pollution event

A serious heavy metal pollution of the Tisza River occurred on March 10, 2000, arising from a mine-dumping site in Romania. Sediment samples were taken from the main riverbed at six sites in Hungary, on March 16, 2000. The objective of this work was to distinguish the anthropogenic and crustal erosion particles in the river sediment. The samples were investigated using both bulk X-ray fluorescence (XRF) and thin-window electron probe microanalysis (EPMA). For EPMA, a reverse Monte Carlo method calculated the quantitative elemental composition of each single sediment particle. A high abundance of pyrite type particles was observed in some of the samples, indicating the influence of the mine dumps. Backscattered electron images proved that the size of particles with a high atomic number matrix was in the range of 2 μm. In other words the pyrites and the heavy elements form either small particles or are fragments of larger agglomerates. The latter are formed during the flotation process of the mines or get trapped to the natural crustal erosion particles. The XRF analysis of pyrite-rich samples always showed much higher Cu, Zn and Pb concentrations than the rest of the samples, supporting the conclusions of the single-particle EPMA results. In the polluted samples, the concentration of Cu, Zn and Pb reached 0.1, 0.3 and 0.2 wt.%, respectively. As a new approach, the abundance of particle classes obtained from single-particle EPMA and the elemental concentration obtained by XRF were merged into one data set. The dimension of the common data set was reduced by principal component analysis. The first component was determined by the abundance of pyrite and zinc sulfide particles and the concentration of Cu, Zn and Pb. The polluted samples formed a distinct group in the principal component space. The same result was supported by powder diffraction data. These analytical data combined with Earth Observation Techniques can be further used to estimate the quantity of particles originating from mine tailings on a defined river section.     

澜沧江中上游流域矿区土壤重金属含量的调查

为了解澜沧江中上游流域矿区的开采和利用对周围生态环境的影响因素,通过选择对该矿区中3种重金属污染物Pb、Cd、Mn进行了调查和实验。确定澜沧江中上游流域的相应采样面,通过湿消化法处理样品,原子吸收光谱法测定了重金属的含量,并作了重金属污染评价。结果表明,澜沧江中上游流域矿区土壤Cd平均值为21.89 mg/kg,超标率为100%,土壤中重金属含量由高到低为Cd,Mn,Pb,重金属之间相关性不显著(P>0.05)。研究区土壤已经被严重污染,单项污染指数由高到低为Cd(21),Pb(0.87),Mn(0.81)。可见澜沧江中上游流域矿区土壤中Pb、Cd、Mn的污染已经呈现出了危害人群健康的趋势,其中Pb、Cd污染最严重,对于重金属污染应采取综合治理措施。     

微束X射线荧光和X射线吸收近边结构谱分析云南某铅锌矿区苔藓中铅的分布和形态

苔藓对重金属胁迫具有良好耐受性和一定的积累能力.本研究采集并测定了铅锌矿区苔藓和苔下土壤中重金属元素含量,利用微束X射线荧光光谱(Micro-X-ray fluorescence spectrometry, micro-XRF)测定了苔藓中重金属元素的分布,采用X射线吸收近边结构(X-ray absorption near edge structure, XANES)分析了苔藓中Pb的元素形态.研究表明,矿区苔藓具有较强的Pb、Zn、Cd、As积累能力,Pb和Zn最高含量可达1.06和1.23 mg/g, Cd和As最高含量可达30.5和13.2 μg/g.苔藓地上部(尤其是新生组织)是苔藓吸收并积累重金属的主要部位;矿区采集的小灰藓和匍枝青藓中部分金属元素分布规律不同,反应了不同苔藓种属对金属元素的吸收、积累和耐受机制的差异.XANES结果显示,Pb在小灰藓中主要以Pb3(PO4)2形态存在(约78%),表明生成Pb3(PO4)2沉淀可能是苔藓对Pb的耐受机制之一.     

Investigations of properties and binding forms of cadmium and nickel in protein extracts by ultra-/diafiltration, photometry and atomic absorption spectrometry

A combination of a special ultrafiltration procedure with photometry and atomic absorption spectrometry for application in the speciation analysis of protein containing solutions is described, allowing not only the determination of qualitative distribution patterns of metal species but also the quantitative characterization of metal species. According to these investigations, exemplified by cadmium and nickel species in protein extracts of bean seeds, it is demonstrated how to use this method. The results show that cadium and nickel have completely different binding mechanisms in these seeds. Furthermore, these investigations lead to the result that the application of membrane separation techniques in speciation analysis is not limited to the separation into molecular weight ranges only. Much more, they are useful techniques in combination with detection methods to obtain information about binding strength and the complexing ability of different matrices to bind heavy metals.     

Speciation of heavy metals in environmental water by ion chromatography coupled to ICP–MS

Biogenic (e.g. phytochelatins, porphyrins, DOM) as well as anthropogenic (e.g. NTA, EDTA, phosphonates) chelators affect the mobility and cycling of heavy metals in environmental waters. Since such chelators can form strongly bound anionic heavy metal complexes that are stable and highly mobile, anion-exchange chromatography coupled to ICP-MS was investigated. A narrow bore HPLC system was connected to a micro concentric nebuliser for in-line sample introduction. A new chromatographic procedure based on a synthetic hydrophilic quaternary ammonium anion exchanger in combination with nitrate as a strong eluent anion, and gradient elution, provided high separation selectivity and a large analytical window. Low detection limits (nmol L(-1)) were achieved by on-column matrix removal and sample preconcentration. This allowed the method to be successfully applied to different environmental research areas. In ecotoxicological studies of heavy metal effects on algae low concentrations of metal EDTA complexes were determined in nutrient solutions without interference from high (buffer) salt concentrations. In groundwater, infiltrated by a polluted river, mobile metal EDTA species were observed. In river water of different pollution levels beside CuEDTA other anionic Cu-complexes were found in nmol L(-1) concentrations.     

Investigation of anthropic effects connected with metal ions concentration, organic matter and grain size in Bormida river sediments

An investigation on the sediment composition and grain size was carried out along the Bormida river (Piedmont, Northern Italy). The samples were taken both in the riverbed and on its banks. Multivariate statistical exploratory methods permitted to identify possible sources of primary pollution. In particular, principal component analysis (PCA) showed that there are probably at least three anthropogenic main causes of pollution, one connected with Cr, Ni and Sn, the second with cadmium and the last one with mercury. Some correlations were found between heavy metal ion concentrations and organic matter and/or the sediment grain size. Differences between the samples collected in the riverbed and on the banks were identified and the relationships between the principal components and the distance of the samples from the riverbed and from the hot spot represented by the ACNA industrial site were also analyzed.     

Heavy Metal Concentrations in Water,Sediment and Fish from Izmit Bay,Turkey

Abstract

Mercury, cadmium and lead levels in water, sediment and fish samples from Izmit Bay, Turkey have been determined. Sampling and analysis methods are described. Variations of heavy metal concentrations from different sampling stations are discussed. Results indicate that the levels of mercury and cadmium were highest in the vicinity of a chlor-alkali plant while the highest concentration of lead was near a metallic pipe factory. The amounts of heavy metals found in the shoreline sediment samples were similar to those found in fish species from the bay.     

Pre-concentration efficiency of chelex-100 resin for heavy metals in seawater : Part 1. Effects of pH and Salts on the Distribution Ratios of Heavy Metals

The chelating characteristics of Chelex-100 resin were studied for selected heavy metals in seawater medium. The results of batch equilibrium and breakthrough experiments show that the metal-chelating efficiency of the resin is lower in seawater than in freshwater. These differences are caused by the complicated speciation of heavy metals in seawater medium and by the high concentrations of magnesium and calcium present which act as competitors to heavy metal ions. The optimal pH values for column operation are strongly affected by the salt matrix. Careful choice of experimental conditions is necessary to avoid losses of cadmium and manganese from seawater. For better performance, seawater samples should be adjusted to pH 6–7 before loading onto a Chelex-100 column.     

Comparison of physicochemical speciation procedures with metal toxicity to chlorella pyrenoidosa

Metal speciation as measured by anodic stripping voltammetry (ASV), adsorption on a resin with adsorbed hydrated aluminium oxide, and dialysis with receiving resins is compared with the toxicity of the metals to the freshwater green alga Chlorella pyrenoidosa Chick. In the presence of natural and synthetic ligands, similar labile fractions of metals were obtained for ASV at three electrodes (hanging mercury drop electrode, mercury film electrode and Nafion-coated mercury film electrode). The toxic fractions determined by ASV and bioassay were in reasonable agreement for zinc, cadmium and copper, and alteration of the analytical conditions provided some measure of agreement for lead. The resin with adsorbed hydrated aluminium oxide correlated well with bioassay for copper, but over-estimated lead toxicity and under-estimated cadmium toxicity. Dialysis with receiving resins under-estimated metal bioaccumulation in the presence of ligands. Metal speciation analysis for water samples gave higher toxic fractions for metals in samples of polluted river water and road runoff samples than those found in pristine river water.     

Heavy-metal distribution in river waters and sediments around a "firefly village", Shikoku, Japan: application of multivariate analysis.

River water and sediment samples were collected at the same site in a vicinity of an abandoned mine, and the concentrations of major elements and heavy metals were determined. The chemical correlations were observed by principal component analysis (PCA), and the samples were classified by cluster analysis (CA) based on the PCA scores. The PCA results presented a macroscopic viewpoint of covariance structure, i.e., the chemical elements could be classified into three groups: 1) major elements and heavy metals in the river water, 2) Cd, Fe and Mn in the sediments, and 3) Cu and Zn in the sediments. The CA results implied a similarity of chemical compositions in most parts of the study area, except the ranges close to the abandoned copper mine. At the mixing location of mining water with natural river water, major elements and cadmium showed simple physical mixing (conservative mixing). Other heavy metals (Cu, Fe, Mn and Zn) showed the massive precipitation at the mixing event. The PCA structure was mainly interpreted in terms of the mixing process between mining water and diluted natural river water.     

Electrothermal atomic absorption spectrometry in the study of metal ion speciation

The literature on the use of electrothermal atomic absorption spectrometry (ETAAS) in the determination of metals in speciation studies of different samples is comprehensively reviewed. The methods of extraction, preconcentration, etc. in connection with speciation studies have been highlighted. The ETAAS programmes and other details of the developed methodologies are discussed. On critical examination it becomes obvious that chromium is the metal which has been analysed by most workers. Study of other metals falls in the following order: Pb, Sn, Cu, As, Al, Cd, Zn, Fe, Ni and Se. It is clearly evident that the major work on metal ion speciation has been carried out in natural water, followed by biological materials. There are also many reports on the speciation analysis of soil and sediment. Only a few papers have been published on metal speciation in airborne particulates. The analytical details of the developed methodologies have been examined in terms of limit of detection, precision and accuracy. Received: 27 December 1995 / Revised: 20 May 1996 / Accepted: 26 May 1996     

Electrothermal atomic absorption spectrometry in the study of metal ion speciation

The literature on the use of electrothermal atomic absorption spectrometry (ETAAS) in the determination of metals in speciation studies of different samples is comprehensively reviewed. The methods of extraction, preconcentration, etc. in connection with speciation studies have been highlighted. The ETAAS programmes and other details of the developed methodologies are discussed. On critical examination it becomes obvious that chromium is the metal which has been analysed by most workers. Study of other metals falls in the following order: Pb, Sn, Cu, As, Al, Cd, Zn, Fe, Ni and Se. It is clearly evident that the major work on metal ion speciation has been carried out in natural water, followed by biological materials. There are also many reports on the speciation analysis of soil and sediment. Only a few papers have been published on metal speciation in airborne particulates. The analytical details of the developed methodologies have been examined in terms of limit of detection, precision and accuracy. Received: 27 December 1995 / Revised: 20 May 1996 / Accepted: 26 May 1996     

Chemical speciation and contamination assessment of Zn and Cd by sequential extraction in surface sediment of Klang River, Malaysia

The concentration and chemical speciation of Cd and Zn as well as total organic carbon (TOC) were studied in surface sediments from 21 stations along Klang River. Sequential extraction technique (SET) was applied to assess the four (exchangeable, acid-reducible, oxidisable-organic and residual) fractions in surface sediment. And also, to obtain an overall classification of cadmium and zinc pollution in this area. This investigation was the first study on the basis of the chemical speciation of Cd and Zn in surface sediments of the Klang River. The total concentrations of metals were ranged (0.60–2.26 µg g^{− 1}) for Cd and (33.26–268.24 µg g^{− 1}) for Zn. The chemical speciation of Cd and Zn in most sampling stations were in the order of residual > acid-reducible > oxidisable-organic > exchangeable, and it showed that the Zn in Klang River surface sediments existed in the nonresistant fractions, whilst Cd existed in the resistant fraction. The degree of surface sediments contamination was determined for individual contamination factors (ICF) and global contamination factor (GCF). The result of ICF and GCF values showed that those stations located vicinity of municipal area had high potential risk to fauna and flora of the Klang River. The relationship between the concentration of cadmium and zinc at the oxidation-organic fraction with TOC in surface sediment was identified. The results showed that TOC had a positive function to complex with Cd and Zn in the surface sediment of Klang River.     

Analytical investigations and chemometrical characterization of polluted soils

Summary Soil samples were taken in the surroundings of an industrial plant with heavy metal emission. A convenient digestion method for the determination of the mobile anthropogenic part of the heavy metal contents of soils was selected. This heavy metal contents were determined by atomic absorption spectrometry. The application of different multivariate statistical methods such as cluster analysis, multi-dimensional variance and discriminant analysis and factor analysis enables the objective characterization of polluted areas and of the degree of pollution as well as the identification of emission sources.     

Speciation analysis of heavy metals in natural waters: a review.

Metal speciation in natural waters is of increasing interest and importance because toxicity, bioavailability, environmental mobility, biogeochemical behavior, and potential risk in general are strongly dependent on the chemical species of metals. This paper provides an overview of the need for speciation of heavy metals in natural waters, the chemical and toxicological aspects of speciation, and the analytical procedures for separation and the different techniques for final determination that are used today. The trends and developments of speciation are also discussed. Finally, the case of chromium (Cr) was selected for a detailed presentation because the speciation of this metal has attracted a great deal of interest in view of the toxic properties of Cr(VI).     

Utilization of optimized BCR three-step sequential and dilute HCl single extraction procedures for soil-plant metal transfer predictions in contaminated lands

The prediction of soil metal phytoavailability using the chemical extractions is a conventional approach routinely used in soil testing. The adequacy of such soil tests for this purpose is commonly assessed through a comparison of extraction results with metal contents in relevant plants. In this work, the fractions of selected risk metals (Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Zn) that can be taken up by various plants were obtained by optimized BCR (Community Bureau of Reference) three-step sequential extraction procedure (SEP) and by single 0.5 mol L(-1) HCl extraction. These procedures were validated using five soil and sediment reference materials (SRM 2710, SRM 2711, CRM 483, CRM 701, SRM RTH 912) and applied to significantly different acidified soils for the fractionation of studied metals. The new indicative values of Al, Cd, Cu, Fe, Mn, P, Pb and Zn fractional concentrations for these reference materials were obtained by the dilute HCl single extraction. The influence of various soil genesis, content of essential elements (Ca, Mg, K, P) and different anthropogenic sources of acidification on extraction yields of individual risk metal fractions was investigated. The concentrations of studied elements were determined by atomic spectrometry methods (flame, graphite furnace and hydride generation atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry). It can be concluded that the data of extraction yields from first BCR SEP acid extractable step and soil-plant transfer coefficients can be applied to the prediction of qualitative mobility of selected risk metals in different soil systems.