Stable isotope tracing of engineered nanoparticles

Engineered nanoparticles (NPs) are increasingly being used in consumer products due to their novel properties. Consequently, concerns have been raised over the potential hazards that these materials may present as a result of their release into the natural environment. This has prompted numerous investigations into the environmental behavior, transport and fate of engineered NPs. Importantly the predicted environmental concentrations of these materials is often x10 to x100 lower than the natural background levels of the element. Many studies overcome this problem with the use of high dosing concentrations, however this raises concerns regarding environmental relevance. The work presented in this thesis demonstrates how stable isotope tracing enables the accurate detection and quantification of engineered NPs in complex biological samples even when exposures are performed at low and environmentally relevant concentrations. This thesis focuses on three of the most prominent commercially available NPs; ZnO, CeO2 and Ag, and covers all aspects of the application of stable isotope labeling and tracing for these materials. This includes; (i) an assessment and evaluation of the technique for application with CeO2 NPs, including the development of chemical separation and mass spectrometric methods for an environmental tracer study, (ii) the assessment of a synthesis protocol for the production of isotopically labeled Ag NPs, and (iii) two environmental tracer studies to assess the uptake and loss of Zn from ZnO NPs by an estuarine snail and earthworm.Open Acces

Transnational organised crime in Europe and North America: towards a framework of prevention

Previous volumes of the HEUNI regional reports have paid little or no attention to transnational organized crime. Although the literature on transnational organized crime (hereafter TOC) is expanding rapidly, there remain fewstandardized measures of the problem. There is even less of a formal framework for thinking about how to prevent TOC in its various forms. The present chapter begins to address these issues, with an emphasis upon practical aspects of the latter. In the following section, TOC is defined and set in a global context, a broad overview of factors relating to recent changes is given, and international legislative responses are described. This is followed by the presentation of a framework that is frequently used in discussions of more general crime prevention efforts. It is proposed that its utilization in this context will help inform the analysis of efforts to prevent TOC

Exposure to nanomaterials in consumer spray products available in the UK

Products containing nanomaterials (NMs) (size < 100 nanometres) are rapidly entering the market, however little is known about inhalation exposures to NMs from their use. Here, we analysed representative consumer spray products available in the UK that claim (or are expected) to contain NMs, to assess potential NM exposure levels during use. In the absence of a UK-focused product inventory, we searched “The Nanodatabase” (nanodb.dk), which listed 269 (out of 3001) products for which inhalation was identified as an exposure pathway. None were available over-the-counter at large stores, but 40 were available on “.co.uk” websites (mainly Amazon). We obtained a representative sample (based on product type and claimed content e.g. silver, silica, gold) and found that 12 out of 16 products contained detectable NMs. We used a multi-method approach to characterise the NMs; inductively-coupled plasma mass spectrometry (ICP-MS), ultraviolet-visible spectroscopy and energy-dispersive x-ray spectroscopy to assess NM composition, and dynamic light scattering, nanoparticle tracking analysis, transmission electron microscopy and single particle ICP-MS to determine particle size and shape. The sizes of the airborne particles/droplets produced by spraying a sub-set (6) of these products were measured using aerodynamic and mobility particle sizers, demonstrating the presence of inhalable aerosols. Whilst 5 out of 6 products clearly contained NMs, only 3 produced aerosols in the nano-size range, suggesting that other constituents (e.g. solvent, fragrance) make up the bulk of the aerosol mass. Using the data generated, quantities of NMs inhaled when using these products can be estimated, which is important for appropriate risk characterisation

Earthworm uptake routes and rates of ionic Zn and ZnO nanoparticles at realistic concentrations, traced using stable isotope labeling

The environmental behavior of ZnO nanoparticles (NPs), their availability to, uptake pathways by, and biokinetics in the earthworm Lumbricus rubellus were investigated using stable isotope labeling. Zinc isotopically enriched to 99.5% in 68Zn (68Zn-E) was used to prepare 68ZnO NPs and a dissolved phase of 68Zn for comparison. These materials enabled tracing of environmentally relevant (below background) NP additions to soil of only 5 mg 68Zn-E kg–1. Uptake routes were isolated by introducing earthworms with sealed and unsealed mouthparts into test soils for up to 72 h. The Zn isotope compositions of the soils, pore waters and earthworms were then determined using multiple collector inductively coupled plasma mass spectrometry. Detection and quantification of 68Zn-E in earthworm tissue was possible after only 4 h of dermal exposure, when the uptake of 68Zn-E had increased the total Zn tissue concentration by 0.03‰. The results demonstrate that at these realistic exposure concentrations there is no distinguishable difference between the uptake of the two forms of Zn by the earthworm L. rubellus, with the dietary pathway accounting for ∼95% of total uptake. This stands in contrast to comparable studies where high dosing levels were used and dermal uptake is dominant

Biodiesel exhaust particle airway toxicity and the role of polycyclic aromatic hydrocarbons

Renewable alternatives to fossil diesel (FD) including fatty acid methyl ester (FAME) biodiesel have become more prevalent. However, toxicity of exhaust material from their combustion, relative to the fuels they are displacing has not been fully characterised. This study was carried out to examine particle toxicity within the lung epithelium and the role for polycyclic aromatic hydrocarbons (PAHs). Exhaust particles from a 20% (v/v) blend of FAME biodiesel had little impact on primary airway epithelial toxicity compared to FD derived particles but did result in an altered profile of PAHs, including an increase in particle bound carcinogenic B[a]P. Higher blends of biodiesel had significantly increased levels of more carcinogenic PAHs, which was associated with a higher level of stress response gene expression including CYP1A1, NQO1 and IL1B. Removal of semi-volatile material from particulates abolished effects on airway cells. Particle size difference and toxic metals were discounted as causative for biological effects. Finally, combustion of a single component fuel (Methyl decanoate) containing the methyl ester molecular structure found in FAME mixtures, also produced more carcinogenic PAHs at the higher fuel blend levels. These results indicate the use of FAME biodiesel at higher blends may be associated with an increased particle associated carcinogenic and toxicity risk

Novel multi-isotope tracer approach to test ZnO nanoparticle and soluble Zn bioavailability in joint soil exposures

Here we use two enriched stable isotopes, 68Znen and 64Znen (>99%), to prepare 68ZnO nanoparticles (NPs) and soluble 64ZnCl2. The standard LUFA 2.2 test soil was dosed with 68ZnO NPs and soluble 64ZnCl2 to 5 mg kg–1 each, plus between 0 and 95 mg kg–1 of soluble ZnCl2 with a natural isotope composition. After 0, 1, 3, 6, and 12 months of soil incubation, earthworms (Eisenia andrei) were introduced for 72 h exposures. Analyses of soils, pore waters, and earthworm tissues using multiple collector inductively coupled plasma mass spectrometry allowed the simultaneous measurement of the diagnostic 68Zn/66Zn, 64Zn/66Zn, and 68Zn/64Zn ratios, from which the three different isotopic forms of Zn were quantified. Eisenia andrei was able to regulate Zn body concentrations with no difference observed between the different total dosing concentrations. The accumulation of labeled Zn by the earthworms showed a direct relationship with the proportion of labeled to total Zn in the pore water, which increased with longer soil incubation times and decreasing soil pH. The 68Znen/64Znen ratios determined for earthworms (1.09 ± 0.04), soils (1.09 ± 0.02), and pore waters (1.08 ± 0.02) indicate indistinguishable environmental distribution and uptake of the Zn forms, most likely due to rapid dissolution of the ZnO NPs

The Use of Pb Isotope Ratios to Determine Environmental Sources of High Blood Pb Concentrations in Children: A Feasibility Study in Georgia

The incidence of lead (Pb) poisoning in children in Georgia has been identified as a major health concern, with a recent national survey identifying that 41% of children aged 2–7 years had blood lead concentrations (BLCs) greater than the blood lead reference value (BLRV) of ≥5 µg dL−1. This study collected samples of blood, spices, paint, soil, dust, flour, tea, toys, milk, and water from 36 households in Georgia where a child had previously been identified as having a BLC > BLRV. The Pb concentrations of these samples were determined and compared to Georgian reference values. Samples from 3 households were analysed for their Pb isotope composition. The Pb isotope composition of the environmental and blood samples were compared to identify the most likely source(s) of Pb exposure. This approach identified that some spice and dust samples were the likely sources of Pb in the blood in these cases. Importantly, some soil, paint, and dust sources with high Pb concentrations could be discounted as contributing to blood Pb based on their distinct isotope composition. The data presented demonstrate the significant contribution that Pb surveillance and Pb isotope ratio analyses can make to managing Pb exposure in regions where high BLCs are identified

Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector

Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT