Abstract  Increased interest in the fate, transport and toxicity of polybrominated diphenyl ethers (PBDEs) over the past few years has led to a variety of studies reporting different methods of analysis for these persistent organic pollutants. Because PBDEs encompass a range of vapor pressures, molecular weights and degrees of bromine substitution, various analytical methods can lead to discrimination of some PBDE congeners. Recent improvements in injection techniques and mass spectrometer ionization methods have led to a variety of options to determine PBDEs in environmental samples. The purpose of this paper is therefore to review the available literature describing the advantages and disadvantages in choosing an injection technique, gas chromatography column and detector. Additional discussion is given to the challenges in measuring PBDEs, including potential chromatographic interferences and the lack of commercial standards for higher brominated congeners, which provides difficulties in examining degradation and debromination of BDE congeners, particularly for BDE 209.

Abstract  This critical review of the available human health safety data, relating to carbon nanotubes (CNTs), was conducted in order to assess the risks associated with CNT exposure. Determining the toxicity related to CNT exploitation is of great relevance and importance due to the increased potential for human exposure to CNTs within occupational, environmental and consumer settings. When this information is combined with knowledge on the likely exposure levels of humans to CNTs, it will enable risk assessments to be conducted to assess the risks posed to human health. CNTs are a diverse group of materials and vary with regards to their wall number (single and multi-walled CNTs are evident), length, composition, and surface chemistry. The attributes of CNTs that were identified as being most likely to drive the observed toxicity have been considered, and include CNT length, metal content, tendency to aggregate/agglomerate and surface chemistry. Of particular importance, is the contribution of the fibre paradigm to CNT toxicity, whereby the length of CNTs appears to be critical to their toxic potential. Mechanistic processes that are critical to CNT toxicity will also be discussed, with the findings insinuating that CNTs can exert an oxidative response that stimulates inflammatory, genotoxic and cytotoxic consequences. Consequently, it may transpire that a common mechanism is responsible for driving CNT toxicity, despite the fact that CNTs are a diverse population of materials. The similarity of the structure of CNTs to that of asbestos has prompted concern surrounding the exposure of humans, and so the applicability of the fibre paradigm to CNTs will be evaluated. It is also necessary to determine the systemic availability of CNTs following exposure, to determine where potential targets of toxicity are, and to thereby direct in vitro investigations within the most appropriate target cells. CNTs are therefore a group of materials whose useful exploitable properties prompts their increased production and utilization within diverse applications, so that ensuring their safety is of vital importance.

Abstract  Polybrominated diphenyl ethers (PBDEs) have been widely used to flame-retard products common in homes and the workplace, and subsequently, they have become widely dispersed in the environment. Detailed compositional knowledge of these complex PBDE mixtures is crucial to a fuller understanding of their toxicological potencies and environmental fate due to selective congener biomagnification, degradation, and transport. Utilizing recenttechnical enhancements and newly available commercial standards, we developed a method capable of analyzing a larger suite of mono- through deca-BDEs. We then characterized the congener composition of six common technical flame-retardant mixtures: two penta-BDE products (DE-71 and Bromkal 70-5DE) two octa-BDE products (DE-79 and Bromkal 79-8DE) and two deca-BDE products (Saytex 102E and Bromkal 82-0DE). PBDEs were analyzed by gas chromatography/mass spectrometry (GC/MS). Structural conformations based on fragmentation patterns and molecular ions were established by electron-capture negative ionization (ECNI) and electron ionization (El). Sixty-four commercially available PBDE standards were chromato-graphed on two GC columns (DB-1HT and DB-5HT) and relative retention indexes (RRI) calculated. Thirty-nine PBDEs were identified in these products, 29 at concentrations >0.02% by weight. Of these, 12 previously unreported congeners have been confirmed as commercial mixture components. Four of these congeners were detected >0.02% w/w (BDE-144, -171, -180, and -201) and three (BDE-75, -184, and -194) at <0.02%. Five other congeners (four <0.02% by weight) were tentatively identified based on their molecular ion and ECNI fragmentation in the absence of corresponding analytical standards.

Abstract  Low-voltage energy-dispersive X-ray microanalysis has a number of distinct advantages for measuring the concentration of light elements (Z = 11-20) in a largely organic matrix. Between 10 and 4 kV, there is a 50-fold decrease in the size of the incident beam-specimen interaction volume which enables discrete subcellular compartments to be analyzed. Experiments with mineral and organic samples of known chemical composition show that two of the most widely used analytical algorithms are capable of providing quantitative data at accelerating voltages as low as 5 kV. This technique is used at 5 kV to analyze frozen hydrated fracture faces of leaves of the tea plant which are known to contain aluminium. Higher levels of aluminium are found in the cell walls and are associated with increased levels of silicon and magnesium. The advantages and disadvantages of the experimental aroach are discussed in relation to analysis carried out at higher voltages.

Abstract  This review describes how a mismatch between the knowledge produced by scientists and the evidence demanded by regulators has emerged, and how society has struggled to find definitive answers to questions of safety, for an important flame retardant chemical in current use - Deca-BDE. This has involved two key disciplines: analytical chemistry and toxicology. Within the chemistry, a lack of standardized methodologies among scientists has resulted in a persistent yet largely undeclared failure to replicate results within the discipline. Within the toxicology, the quest for innovative, curiosity-driven research by university scientists in preference to using validated standard protocols, designed to promote consistency within the risk assessment process, has prompted questions about the credibility and relevance of scientific findings. Yet scientific laboratories have compelling reasons to do things the way they do in the cause of producing new knowledge, pointing to a sustained gap between the aims and practices of research scientists and those of risk management. A more rigorous scientific process that treats different elements of input data as discrete pieces of evidence is needed to ensure that science rather than politics will always define chemical safety.

Abstract  The advantages and drawbacks of using instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS) for soil, sediment, plant and water pollution studies are discussed. The experimental procedures used for each method and for each type of sample matrix are described. They were tested on several certified reference materials. The results obtained on these materials showed good agreement for many elements for which the two techniques are suited, and they were complementary for the other elements which are also of environmental interest. An element-by-element assessment is presented to indicate the precautions to be taken and the most convenient technique for each of them.

Abstract  During the past 20 years, multiwall carbon nanotubes (MWCNTs) have become an important industrial material. Hundreds of tons are produced each year. This review is a survey of the scientific literature, motivated by industrial requirements and guidelines for environment, health and safety compliance. Sampling, size, area, density, color, crystallinity, as well as purity compared to properties of non-MWCNT carbon and catalyst metals, are presented. No single measurement tool provides a complete characterization; therefore, we summarize methods that include scanning electron microscopy, transmission electron microscopy (TEM), fast Fourier transform of high-resolution TEM, Raman spectroscopy, reflectance and thermogravimetric analysis. Fourier transform infrared spectroscopy reveals information with regard to functional groups interacting the tube surface. Brunauer–Emmett–Teller (BET) analysis is reviewed as the basis for evaluating specific surface area. We extend the review by presenting taxonomy of defects present in MWCNTs. Finally, we provide an appendix from documentary standards that are pertinent and reasonable for bulk measurements.

Abstract  The recent emergence of manufactured nanoparticles (NPs) that are released into the environment and lead to exposure in organisms has accelerated the need to determine NP toxicity. Techniques for measuring the toxicity of NPs (nanotoxicology) in ecological receptors (nanoecotoxicology) are in their infancy, however, and establishing standardized ecotoxicity tests for NPs are presently limited by several factors. These factors include the extent of NP characterization necessary (or possible) before, during, and after toxicity tests such that toxic effects can be related to physicochemical characteristics of NPs; determining uptake and distribution of NPs within exposed organisms (does uptake occur or are effects exerted at organism surfaces?); and determining the appropriate types of controls to incorporate into ecotoxicity tests with NPs. In this review, the authors focus on the important elements of measuring the ecotoxicity of carbon NPs (CNPs) and make recommendations for ecotoxicology testing that should enable more rigorous interpretations of collected data and interlaboratory comparisons. This review is intended to serve as a next step toward developing standardized tests that can be incorporated into a regulatory framework for CNPs.