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.     

Environmental,toxicological and biomedical research on trace metals: Radiochemical separations for neutron activation analysis

Twenty-two radiochemical separation procedures for neutron activation analysis (NAA) of environmental and biological samples are presented. They are currently applied in the context of trace metal research related to the protection of the environment and human health. The radiochemical procedures are related to the separations of the elements into groups which allow the determination of up to 50 elements in each sample or to specific separations for single elements. The experience gained in the application of these radiochemical separations over more than ten years allows us to consider them as reliable for sensitive determinations of trace metals in environmental and biological samples.     

微量元素在医学地质中的研究进展述评

人体中有益元素的缺乏或有毒有害元素过量导致众多健康问题,微量元素在医学地质研究中占有举足轻重的作用。随着医学地质研究的不断深入和新技术的快速发展,微量元素的研究领域和研究程度也不断扩大和深入,该文综述了微量元素在医学地质中的主要研究内容,研究方法及风险评价,指出了微量元素研究的薄弱环节及其发展趋势,以期推动进一步研究。     

An overview of sample preparation procedures for LC-MS multiclass antibiotic determination in environmental and food samples

Antibiotics are a class of pharmaceuticals that are of great interest due to the large volumes of these substances that are consumed in both human and veterinary medicine, and due to their status as the agents responsible for bacterial resistance. They can be present in foodstuffs and in environmental samples as multicomponent chemical mixtures that exhibit a wide range of mechanisms of action. Moreover, they can be transformed into different metabolites by the action of microorganisms, as well as by other physical or chemical means, resulting in mixtures with higher ecotoxicities and risks to human health than those of the individual compounds. Therefore, there is growing interest in the availability of multiclass methods for the analysis of antimicrobial mixtures in environmental and food samples at very low concentrations. Liquid chromatography (LC) has become the technique of choice for multiclass analysis, especially when coupled to mass spectrometry (LC-MS) and tandem MS (LC-MS²). However, due to the complexity of the matrix, in most cases an extraction step for sample clean-up and preconcentration is required before analysis in order to achieve the required sensitivities. This paper reviews the most recent developments and applications of multiclass antimicrobial determination in environmental and food matrices, emphasizing the practical aspects of sample preparation for the simultaneous extraction of antimicrobials from the selected samples. Future trends in the application of LC-MS-based techniques to multiclass antibiotic analysis are also presented.     

Recent on-line processing procedures for biological samples for determination of trace elements by atomic spectrometric methods

Few of the elements present in nature play a metabolic role in living organisms. According to their abundance, these elements are classified as macro-, micro- or trace elements, representing 93%, 5% and around 1% respectively, of the total body weight. The remaining percentage could be attributed to those elements with unknown biological functions, to others which are present only because of the exposure to polluted environment or to those intentionally introduced into the body for a special treatment. This review summarizes and discusses the most recent publications related to the on-line processing of biological samples for trace element determination using atomic spectrometry-based detectors. Preconcentration/separation procedures based on solid phase or cloud point extractions, electrochemical deposition, microdialysis, as well as chemical vapor generation are the common practice for improving the sensitivity and selectivity of the available atomic spectrometric techniques. The advantages of using isotope dilution mass spectrometry in speciation studies are also emphasized. Digestion or leaching in oxidizing acidic mixtures aided by heat or by ultrasound or microwave radiation, performed off- or on-line, is necessary to previous steps when processing solid biological samples. The most relevant analytical figures of merit such as detection limits, enrichment factors and sample throughput as well as some aspects related to the on-line system configurations and accuracy assessments are critically presented.     

An Overview of the Analytical Methods for the Determination of Organic Ultraviolet Filters in Cosmetic Products and Human Samples

UV filters are a group of compounds commonly used in different cosmetic products to absorb UV radiation. They are classified into a variety of chemical groups, such as benzophenones, salicylates, benzotriazoles, cinnamates, p-aminobenzoates, triazines, camphor derivatives, etc. Different tests have shown that some of these chemicals are absorbed through the skin and metabolised or bioaccumulated. These processes can cause negative health effects, including mutagenic and cancerogenic ones. Due to the absence of official monitoring protocols, there is an increased number of analytical methods that enable the determination of those compounds in cosmetic samples to ensure user safety, as well as in biological fluids and tissues samples, to obtain more information regarding their behaviour in the human body. This review aimed to show and discuss the published studies concerning analytical methods for the determination of organic UV filters in cosmetic and biological samples. It focused on sample preparation, analytical techniques, and analytical performance (limit of detection, accuracy, and repeatability).     

激光剥蚀串联电感耦合等离子体质谱在环境分析中的应用进展

激光剥蚀串联电感耦合等离子体质谱法(LA-ICP-MS)是一种功能强大的化学元素检测方法,它具有样品前处理简单、多元素同时测定、高通量、高灵敏度、宽线性范围以及原位分析等优点。同时,激光剥蚀可以与多接收器电感耦合等离子体质谱仪(MC-ICP-MS)串联用于稳定同位素组成测定,不仅避免了繁琐的样品前处理,同时还可应用于固体样品的微区原位同位素分析,揭示微观尺度上稳定同位素组成的变化。LA-ICP-MS已广泛应用于地质、考古等领域,其在环境科学领域应用相对起步较晚,但近年来发展迅速。该文总结了近年来LA-ICP-MS的环境分析方法开发及其在环境科学中的应用进展,并对其未来发展趋势进行了展望。     

Environmental exposure to metals of newborns, infants and young children

Anthropogenic emissions, such as those from combustion of fossil fuel, waste incineration and industrial use, contribute to higher levels of metal pollutants, including Cd, Pb and Sb, in the urban environment. These widespread and persistent environmental pollutants have the potential for developmental and reproductive toxicity. Health risks are particularly associated with exposure in utero and the early years of life, since the developing organism is at greater risk from permanent damage, and both absorption and retention can be considerably greater in infants than adults. In order to assess risk to humans, the information on environmental levels of pollutants (environmental monitoring) should be integrated with information on biomarkers of exposure, effect or susceptibility in biological fluids or tissues (biological monitoring). The analysis of tissue from the target organ obtained at autopsy provides a direct record of the accumulation of toxins and allows temporal and geographical trends to be studied. Few literature reports on tissue content of potentially toxic elements include data on newborns and young children since collections of autopsy samples in this age range are rare. Existing data are sometime questionable, because of inadequate sensitivity of the analytical techniques, insufficient control of contamination and lack of validation. Our recent work aimed to establish reliable reference values for the content of Cd, Pb and Sb in the liver of pediatric subjects.     

Reporter gene bioassays in environmental analysis

In parallel to the continuous development of increasingly more sophisticated physical and chemical analytical technologies for the detection of environmental pollutants, there is a progressively more urgent need also for bioassays which report not only on the presence of a chemical but also on its bioavailability and its biological effects. As a partial fulfillment of that need, there has been a rapid development of biosensors based on genetically engineered bacteria. Such microorganisms typically combine a promoter-operator, which acts as the sensing element, with reporter gene(s) coding for easily detectable proteins. These sensors have the ability to detect global parameters such as stress conditions, toxicity or DNA-damaging agents as well as specific organic and inorganic compounds. The systems described in this review, designed to detect different groups of target chemicals, vary greatly in their detection limits, specificity, response times and more. These variations reflect on their potential applicability which, for most of the constructs described, is presently rather limited. Nevertheless, present trends promise that additional improvements will make microbial biosensors an important tool for future environmental analysis.     

Characterization of carbon nanotubes and analytical methods for their determination in environmental and biological samples: A review

In the present paper, a critical overview of the most commonly used techniques for the characterization and the determination of carbon nanotubes (CNTs) is given on the basis of 170 references (2000–2014). The analytical techniques used for CNT characterization (including microscopic and diffraction, spectroscopic, thermal and separation techniques) are classified, described, and illustrated with applied examples. Furthermore, the performance of sampling procedures as well as the available methods for the determination of CNTs in real biological and environmental samples are reviewed and discussed according to their analytical characteristics. In addition, future trends and perspectives in this field of work are critically presented.     

Sample handling strategies for the determination of persistent trace organic contaminants from biota samples

Even after emergence of most advanced instrumental techniques for the final separation, detection, identification and determination of analytes, sample handling continues to play a basic role in environmental analysis of complex matrices. In fact, sample preparation steps are often the bottleneck for combined time and efficiency in many overall analytical procedures. Thus, it is not surprising that, in the last two decades, a lot of effort has been devoted to the development of faster, safer, and more environment friendly techniques for sample extraction and extract clean up, prior to actual instrumental analysis. This article focuses on the state of the art in sample preparation of environmental solid biological samples dedicated to persistent organic pollutants (POPs) analysis. Extraction techniques such as Soxhlet extraction, sonication-assisted extraction, supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), pressurised liquid extraction (PLE) and matrix solid-phase dispersion (MSPD) are reviewed and their most recent applications to the determination of POPs in biota samples are provided. Additionally, classical as well as promising novel extraction/clean-up techniques such as solid phase microextraction (SPME) are also summarized. Finally, emerging trends in sample preparation able to integrate analytes extraction and their adequate clean-up are presented.     

Analytical methodologies for the determination of nitroimidazole residues in biological and environmental liquid samples: A review

Nitroimidazoles (NDZs) are antiprotozoal drugs that are typically used in veterinary and human medicine. NDZs and their metabolites are believed to possess genotoxic, carcinogenic and mutagenic properties, and this is (one reason) why their use has been banned within the European Union. Hence, the determination of trace residues of these substances in edible animal tissues has been of growing concern over the past few years. Even, though there has been a need to develop sensitive and reliable analytical methods to study the residues of these compounds in different matrices, available methodologies in environmental samples are rather limited. These and other pharmaceutical compounds have become one of the most important new classes of environmental pollutants that have been detected in wastewater-treatment-plant (WWTP) effluents, receiving waters, drinking water and groundwater. A compilation of the most representative analytical methodologies for the determination of NDZ residues during the last decade is presented in this paper. Its scope is the two main areas which require their determination, namely biological and environmental matrices. A detailed explanation of both areas, including sample treatment and detection systems, and future trends is presented, focusing on the difficulties of confirming analytes at low concentration levels.     

Groundwater Quality at the Huaibei Coalfield,China

The environmental and health impacts of trace elements are of great concern because of their toxicity, persistence, and bioavailability. Twenty-six groundwater samples were collected from the coal mining areas to evaluate water quality and potential environmental impact caused by mining activities. The physical/chemical properties and trace element concentrations (As, Cd, Cr, Cu, Pb, and Zn) were determined. The physical/chemical parameters and the concentrations of trace elements varied among the shallow and confined groundwater, which may indicate the absence of hydraulic interactions between the aquifers. The concentrations of trace elements in the mining areas are higher than at background monitoring sites, which suggests that the mining activities may lead to environmental and health impacts. Based on a health risk assessment, the low hazard quotients and cancer risk values in confined groundwater samples indicate that the chronic and cancer adverse effects due to trace elements are negligible. This study provides a comprehensive assessment of groundwater trace element impacts from coal mining in China and is useful for environmental management.     

Elimination of Inteferences in Trace Element Determination by Graphite Furnace Atomic Absorption Spectrometry

Graphite furnace atomic absorption spectrometry has been recognized as one of the most sensitive and selective analytical techniques for trace element determination. It is especially suitable for the measurement of parts-per-billion levels of essential or toxic elements like selenium,arsenic, germanium or lead in environmental and biological samples.     

Recent advances in on-line coupling of capillary electrophoresis to atomic absorption and fluorescence spectrometry for speciation analysis and studies of metal-biomolecule interactions

Speciation information is vital for the understanding of the toxicity, mobility and bioavailability of elements in environmental or biological samples. Hyphenating high resolving power of separation techniques and element-selective detectors provides powerful tools for studying speciation of trace elements in environmental and biological systems. During the last five years several novel hybrid techniques based on capillary electrophoresis (CE) and atomic spectrometry have been developed for speciation analysis and metal-biomolecule interaction study in our laboratory. These techniques include CE on-line coupled with atomic fluorescence spectrometry (AFS), chip-CE on-line coupled with AFS, CE on-line coupled with flame heated quartz furnace atomic absorption spectrometry (FHF-AAS), and CE on-line coupled with electrothermal atomic absorption spectrometry (ETAAS). The necessity for the development of these techniques, their interface design, and applications in speciation analysis and metal-biomolecule interaction study are reviewed. The advantages and limitations of the developed hybrid techniques are critically discussed, and further development is also prospected.     

Epigenetics: an important challenge for ICP-MS in metallomics studies

Trace metal analysis has been long regarded as one of the principle tasks in areas of chemical analysis. At the early stage of instrumental development, total concentration was assessed in a variety of samples, yielding results, among others, for environmental, biological, and clinical samples. With the power of newer analytical techniques, such as inductively coupled plasma mass spectrometry (ICP-MS), accurate quantitative results can now be obtained at ultra-trace levels not only for metals, but also for metalloids and several non-metals. Even though the importance of trace elements in many biological processes is widely accepted, the elucidation of their biological pathways, understanding specific biological functions, or possible toxicological aspects is still a challenge and a driving force to further develop analytical methodology. Over the past decades, the scientific interest has moved from total element determination to include speciation analysis, which provides quantitative information of one or more individual element species in a sample. More recently, metallomics has been introduced as a more expanded concept, in which the global role of all metal/metalloids in a given system is considered. Owing to the multi-elemental focus of metallomics research, the use of ICP-MS becomes indispensable. Furthermore, considering the biological role of metals/metalloids and the use of elements as internal or external molecular tags, epigenetics should be considered as an important emerging application for metallomics studies and approaches. Among a variety of epigenetic factors, essential nutrients, but also environmental toxins, have been shown to affect DNA methylation, modification of histone proteins, and RNA interference, all of them being implicated in cancer, cardiovascular disease, and several inherited conditions. Recent studies suggest that epigenetics may be a critical pathway by which metals produce health effects. In this Trends article, the basic epigenetic concepts are introduced, followed by the early applications of ICP-MS classified as: (i) detection of ³¹P as a natural element tag for DNA, (ii) analysis of DNA adducts with metal-based drugs, (iii) element species as epigenetic factors.     

The role of element speciation in environmental and occupational medicine

In order to evaluate the interaction with the environment or to assess absorption, binding mechanisms, reactivity and excretion of elements in humans, element speciation can provide more information than the analysis of element as a whole. Some examples that confirm the importance of speciation depend on the choice of the most appropriate indicator or representative matrix. The determination of As(III), As(V), monomethylarsonic and dimethylarsinic acids can be used to evaluate occupational exposure to As. Exposure to inorganic Hg should be measured by its content in urine, whereas in the case of exposure to alkyl Hg, blood and hair should be considered. Speciation may also be useful in studying element toxicokinetics, since it is well known that hexavalent Cr is taken up more than the trivalent form, and that species of the same metal are differently partitioned in blood. Pentavalent forms of As are absorbed more than trivalent forms, and the organic species of elements are excreted faster than inorganic species. In addition, speciation can play an important role in assessing element toxicodynamics. The toxicity of the three oxidation states of Hg differs considerably; for As a decreasing toxicity from arsenite to dimethylarsinic acid is proposed; for organotin compounds, higher toxicity for ethyl groups than for phenyl groups is reported. However, speciation in biological media is difficult when applied to other elements because of the lack of information on the existence and significance of species whose determination could be valuable. Furthermore, there may be no analytical methods that allow an accurate measurement of the species. The feasibility of speciation in occupational and environmental medicine depends mainly on our capability to solve some problems related to the identification and determination of species and on the demonstration that species measurement represents a clear improvement compared to total element determination.     

Uses of speciation techniques in biomonitoring for assessing human exposure to organic environmental chemicals

Speciation analysis has been used for many years to identify and measure different forms of a given chemical in environmental and human samples. Although the term speciation is generally applied to the measurement of inorganic chemicals, the term can also be applied to many measurements of organic chemicals in complex samples, such as environmental media and biological matrices. We present several examples of achieving speciation analysis by selecting the appropriate biological matrix in which to measure a specific chemical(s), by a given analytical method, for the most accurate assessment of human exposure to the environmental chemical. Much of this information and many of these techniques are transferable to the measurement of inorganic elements in environmental and biological samples.     

A Primer on the Analytical Aspects of Silicones at Trace Levels-Challenges and Artifacts – A Review

Silicones (polydimethylsiloxanes) find use in a wide variety of industrial and consumer product applications because of their outstanding properties. Potential human exposure to silicones occurs at the work place during manufacturing and product formulation, as well as through the normal use of consumer products containing them.The entry of silicones into various environmental compartments raised health and safety concerns from potential exposure and mandated numerous environmental and toxicological studies. Such studies require qualitative and quantitative determination of silicone species at trace levels. However, the ubiquitous presence of silicones coupled with their unique chemistry renders their analysis at trace levels challenging.This paper provides a consolidated account of various aspects silicones that must be borne in mind to obtain reliable data. The following are some of topics discussed: differences in the chemistry of silicones vs carbon; precautions in sample handling to avoid losses and inadvertent chemical transformation; potential sources for artifacts and interferences that could lead to systematic errors and data misinterpretation; sources for background and the need for matrix matched blank experiments; distinguishing silicones from silicates to avoid overestimation; potential for incorrect structural assignments; preventing inadvertent contamination; questionable claims on the presence of silicones in biological matrices including that of silicone implants.     

环境致癌物风险评价和生物标记物研究*

反映暴露水平与生物效应等重要信息的生物标记物研究是环境致癌物风险评价的核心内容。本文综述了环境化学致癌物风险性评价和生物标记物的研究现状与发展前景, 以及生物标记物在风险性优先顺序的战略规划过程中所起的重要作用。