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).     

Heavy metals in lake water: a review on occurrence and analytical determination

Many lakes especially in Asia are source of livelihood for the surrounding communities. With increased urbanisation and industrialisation, however, these lakes are threatened with emerging environmental contaminants, including heavy metals. Some heavy metals are harmful to human health and the environment. This review aims to describe the different sampling, sample preparation and pretreatment, and instrumental methods of analysis for heavy metals in lake water. Filtration and acid digestion are common sample treatment methods used prior to analytical determination. Atomic absorption spectroscopy and inductively-coupled plasma – mass spectrometry (ICP-MS) are typical analytical techniques but nowadays ICP-MS is frequently used. This review also describes the sources and extent of heavy metals contamination in different lakes. Although some lakes still have natural levels of heavy metals in the water, many have elevated concentrations due to anthropogenic sources, such as vehicular, household, agricultural, industrial and mining activities.     

Recent applications of atomic spectroscopy coupled with magnetic solid-phase extraction techniques for heavy metal determination in environmental samples: A review

Atomic spectroscopy is the most popular approach to determine the presence of heavy metals in the environment. Heavy metals are potentially toxic and have various negative effects on many living organisms, including humans. With the rapid increase in the variety of industries and human activities, large amounts of heavy metals are released into the atmosphere, water, and soil. Heavy metal analysis of environmental samples is very important for determining the exposure limits. Environmental samples are highly complex matrices, and various sample preparation techniques have been developed for the extraction of heavy metals from them, including magnetic solid-phase extraction (MSPE). The use of MSPE in heavy metal analysis has recently gained significant attention owing to a number of advantages. MSPE technique overcomes main issues such as phase separation, handling, and column packing. The use of magnetic adsorbents in sample preparation has grown over the past few years, making MSPE a promising technique for sample preparation. The objective of this review article is to provide the latest applications of MSPE coupled with atomic spectroscopy for heavy metal determination in environmental samples. In addition, new magnetic adsorbents and their analytical merits are emphasized.     

核酸适配体-荧光传感技术在重金属检测领域的应用

重金属污染环境后难以自然降解或无害化,进入有机体后有较强的生物蓄积性,会对环境安全和人类健康造成巨大威胁;此外,有些高毒重金属离子还可作为蓄意投毒、威胁恐吓的恐怖剂.因此,对环境中的重金属离子实现快速、现场检测尤为重要.传统仪器检测方法前处理复杂、成本高、操作需要专业人员,现场应用受限.近年来随着技术的发展和新材料的应...     

Determination of toxic and trace elements in algae by instrumental neutron activation analysis

Instrumental neutron activation analysis has been applied in the determination of toxic and other trace elements in a set of three algae materials provided by the International Atomic Energy Agency, with the aim of environmental preservation through enhanced applications of nuclear analytical techniques. The quality of the analysis method has been evaluated by analyzing a number of biological standard reference materials. By adding mineral nutrients, the cultivation of algae for metals is enhanced, in particular, selected toxic heavy metals such as As, Cd, Cr, Hg, Ni and Pb. It is believed that the level of elemental concentration in algae samples are dependent on environmental conditions due to its biochemical properties. Therefore, algae materials may be useful as an indicator or controller of environmental water pollution.     

流动注射分析在环境水质重金属检测中的应用进展

重金属具有毒性大、不易被代谢、易被生物富集并有生物放大效应等特点,不但污染水环境,也严重威胁人类和水生生物的存在。近年来各类水环境中重金属污染日趋加剧,重金属的检测及处理方法有多种,而流动注射分析技术以其自动化程度高、分析速度快、精密度高、分析成本低等优点在水环境监测方面占有重要地位。介绍了流动注射在重金属检测方面的应用。     

细菌介导重金属转化过程及金属组学研究方法

重金属污染依然是我国严重的环境问题之一。在重金属胁迫下,微生物可通过复杂的过程,对重金属进行转化,降低重金属的毒性,其中转化涉及的分子机制广受关注。目前,在上述机制相关研究中,对转化过程中重金属的衡量多局限于总量的测定,而对其赋存形态的研究不足,导致难以取得有效进展。对细菌介导重金属的转化过程及金属在其中的赋存形态进行综述,探讨了金属组学研究方法在其中的应用,重点针对重金属的颗粒态与蛋白质结合态进行分析、表征和鉴定,为微生物介导重金属的转化研究提供新视角。     

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。     

Removal,recovery and enrichment of metals from aqueous solutions using carbon nanotubes

Environmental pollution caused by toxic metals (heavy metals, radioactive metals, etc.) is one of the major global issues, thus removal of toxic metals from contaminated water seems to be particularly important. On the other hand, the recovery and enrichment of metals, especially noble metals, from waste water is also crucial. To address these issues, nanotechnology plays an essential role in environmental monitoring and pollution control. To remove metals from contaminated water, or enrich metals from waste water, carbon nanotubes (CNTs) and their composites have attracted great attention due to their excellent adsorption performance. The removal efficiency for metal ions by CNTs was observed aroud 10–80 %, which could be improved to approach 100 % by selectively functionalizing CNTs with organic ligands. Herein, we review the applications of CNTs in treatment of toxic metal-containing wastewater for environmental monitoring and metals recovery. Due to their higher sensitivity and selectivity towards the enrichment of metals or detection of toxic metal pollution of the environment, and the latest research progress of using CNT composites for metal treatment is also discussed.     

Trace analysis of metals in plant samples with inductively coupled plasma – mass spectrometry

An analytical method for the quantitative determination of Al, Ti, V, Cr, Co, Ni, Cu, Zn, Mo, Cd, Ti and Pb in plant samples by ICP-MS has been developed. Spectral interferences, plant matrix effects, precision and accuracy are discussed. Results are demonstrated for selected samples concerned with the mass balance of heavy metals after utilization of non-food vegetable materials in a power plant. Received: 7 January 1997 / Revised: 2 June 1997 / Accepted: 18 June 1997     

Sensitive detection of heavy metals ions based on the calixarene derivatives-modified piezoelectric resonators: a review

Heavy-metal pollution is a foremost concern, as excessive heavy metals produce environmental contamination, and the accumulative effects of heavy metals pose a major hazard to human health. There is an urgent need for a fast, sensitive and effective method for detecting heavy metal cations in the environment. In recent years, using Quartz Crystal Microbalance (QCM) technique, significant progress was achieved in quantitative analysis by providing a new approach for determination of chemical content analysis. The objective aim of this review is to assess the research development of QCM applications in detection of heavy metal cations in natural water (or aqueous solution) and reflect the challenges and forthcoming point of view for QCM-based sensors for heavy-metal ions. A brief outline about the basic measurement methodologies and analytical techniques is given. To illustrate applications of the QCM techniques, the influence of the structural transformation resulting from polymer, macrocyclic ‘calixarenes’ and nanostructural coating on sensation will be discussed. Lastly, we summarise fields of applications and future forecast for the utilisation of functionalised QCM surface as a chemical sensor to study the interaction of heavy metal ions with calixarenes.     

The Application of Microelectrodes for the Measurements of Trace Metals in Water

Abstract

The analytical approaches for the determination of trace concentrations of heavy metals in aquatic systems are briefly introduced. A detailed review on the recent advances of microelectrodes is presented, including the definitions, types, advantages, theory, and fabrication of microelectrodes. The application of microelectrodes on the measurements of trace metals in water is focused on the voltammetric‐, potentiometric‐, and in situ electrochemical sensors.     

Overview of analysis of carcinogenic and/or mutagenic metals in biological and environmental samples. I. Arsenic, beryllium, cadmium, chromium and selenium

One of the most dangerous and pernicious forms of pollution arises from the potential mobilization of a spectrum of toxic trace metals and metalloids in our environment. Among the most important elements in this regard are arsenic, beryllium, cadmium, chromium and selenium whose adverse toxic effects are now well recognized including their carcinogenicity and/or mutagenicity. These agents (and their derivatives) can be widely dispersed throughout the environment as a result of fossil fuel combustion, industrial and agricultural processes and natural processes. The trend for the immediate future appears to be of greater exposure to these metals not only as a result of generally increased usage patterns but also because of prospective enhanced use of fossil fuels for space heating and electricity generation. In order to more readily evaluate trends of human exposure as well as the toxicity, bioavailability, bioaccumulation and transport of these elements, sensitive analytical procedures are required for the determination of their various oxidation states (as well as their organic derivatives) in complex matrices such as those found in both environmental and biological samples. Hence, the principal objective of this overview is to highlight the more recent trends and state-of-the-art methodologies for the determination of arsenic, beryllium, cadmium, chromium and selenium (in their various forms) in environmental compartments such as air, water, soil and in human tissues (primarily blood, urine, and milk). Techniques to be discussed primarily include atomic absorption spectrometry, neutron activation analysis, gas chromatography, differential pulse polarography and electrochemical analysis. The importance of quality control and differentiation according to speciation will also be stressed.     

Application of instrumental neutron activation analysis and inductively coupled plasma-mass spectrometry to studying the river pollution in the State of Minas Gerais

Instrumental neutron activation analysis (INAA) and inductively coupled plasma-mass spectrometry (ICP-MS) have been used for the determination of toxic heavy metals and other pollutants in the water of the Das Velhas river in the State of Minas Gerais, in south-east Brazil. Elemental concentrations of about 60 elements were measured in water samples collected to different parts of this river and from two affluents. There was a good agreement between the two analytical methods and the results were complementary. The results indicated an increase in the concentration of several polluting elements in the water from mining industry area.     

Determination of heavy metals in welder's working environment using nuclear analytical methods

Technological process of welding is significant source of pollution of working environment with heavy metals. Evaluation of chemical quality of working environment was made by means of radionuclide X-ray fluorescent analysis and activation analysis with fast neutrons. Welding aerosols were sampled by filtration method on Synpor 4 membrane ultra-filters. For selected types of welding filter metals, determination of heavy metals in aerosols was performed.     

Inert sampling and sample preparation - the influence of oxygen on heavy metal mobility in river sediments

Two approaches have been used to investigate changes in the nature of metal binding in river sediments caused by atmospheric oxygen. Firstly, non-inert and inert sample preparation were applied, in combination with sequential extraction, to determine for which metals inert sample preparation is necessary for correct determination of metal mobility under environmental conditions. Secondly, the metal contents of sediments sampled before and after a river weir were fractionated by sequential extraction to study the effect of the oxygen impact at the weir on heavy metal mobility in the sediments. Different grain-size fractions from one sample were also extracted, to enable selection of the upper grain-size limit most suitable for answering this analytical question. The results showed the need for the inert sample preparation technique for Cd, Zn, Pb, Mn, and Fe, but not for Co, Ni, Cu, and Cr. No significant change of heavy metal mobility at the weir could be proved, although the mobilization behavior of some elements was different. The optimum upper grain-size limit was 63 microm.     

Heavy Metals and Human Health: Possible Exposure Pathways and the Competition for Protein Binding Sites

Heavy metals enter the human body through the gastrointestinal tract, skin, or via inhalation. Toxic metals have proven to be a major threat to human health, mostly because of their ability to cause membrane and DNA damage, and to perturb protein function and enzyme activity. These metals disturb native proteins’ functions by binding to free thiols or other functional groups, catalyzing the oxidation of amino acid side chains, perturbing protein folding, and/or displacing essential metal ions in enzymes. The review shows the physiological and biochemical effects of selected toxic metals interactions with proteins and enzymes. As environmental contamination by heavy metals is one of the most significant global problems, some detoxification strategies are also mentioned.     

Evaluating the state-of-the-practice in soil measurements in relation to environmental regulations

 The results of chemical analyses of soils show large variations due to the heterogeneity of the material, differences in pretreatment and analytical methods, and unavoidable random errors. In this article, the analytical aspects in the determination of heavy metals in soils are highlighted. Both within-laboratory and between-laboratory variation must be minimized by validation and standardization procedures, respectively, in order to keep the variations resulting from the analytical procedure at an acceptably low level. Even then, the best results will show uncertainties of 5–20%, an issue that should be recognized by governmental and legal bodies. Received: 9 November 1995 Accepted: 1 December 1995     

Determination of heavy metal ions by microchip capillary electrophoresis coupled with contactless conductivity detection

An integrated detection circuitry based on a lock-in amplifier was designed for contactless conductivity determination of heavy metals. Combined with a simple-structure electrophoresis microchip, the detection system is successfully utilized for the separation and determination of various heavy metals. The influences of the running buffer and detection conditions on the response of the detector have been investigated. Six millimole 2-morpholinoethanesulfonic acid + histidine were selected as buffer for its stable baseline and high sensitivity. The best signals were recorded with a frequency of 38 kHz and 20 V(pp). The results showed that Mn(2+), Cd(2+), Co(2+), and Cu(2+) can be successfully separated and detected within 100 s by our system. The detection limits for five heavy metals (Mn(2+), Pb(2+), Cd(2+), Co(2+), and Cu(2+)) were determined to range from about 0.7 to 5.4 μM. This microchip system performs a crucial step toward the realization of a simple, inexpensive, and portable analytical device for metal analysis.