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

An evaluation of the fixed concentration procedure for assessment of acute inhalation toxicity

Acute inhalation studies are conducted in animals as part of chemical hazard identification and for classification and labelling. Current methods employ death as an endpoint (OECD TG403 and TG436) while the recently approved fixed concentration procedure (FCP) (OECD TG433) uses fewer animals and replaces lethality as an endpoint with evident toxicity. Evident toxicity is the presence of clinical signs that predict that exposure to the next highest concentration will cause severe toxicity or death in most animals. Approval of TG433 was the result of an international initiative, led by the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), which collected data from six laboratories on clinical signs recorded for inhalation studies on 172 substances. This paper summarises previously published data and describes the additional analyses of the dataset that were essential for approval of the TG

A controlled cross-over study to evaluate the efficacy of improvised dry and wet emergency decontamination protocols for chemical incidents

The UK Initial Operational Response (IOR) to chemical incidents includes improvised decontamination procedures, which use readily available materials to rapidly reduce risk to potentially exposed persons. A controlled, cross-over human volunteer study was conducted to investigate the effectiveness of improvised dry and wet decontamination procedures on skin, both alone, and in sequence. A simulant contaminant, methyl salicylate (MeS) in vegetable oil with a fluorophore was applied to three locations (shoulder, leg, arm). Participants then received no decontamination (control) or attempted to remove the simulant using one of three improvised protocols (dry decontamination; wet decontamination; combined dry and wet decontamination). Simulant remaining on the skin following decontamination was quantified using both Gas Chromatography Tandem Mass Spectrometry (GC-MSMS) for analysis of MeS and UV imaging to detect fluorophores. Additionally, urine samples were collected for 24 hours following application for analysis of MeS. Significantly less simulant was recovered from skin following each improvised decontamination protocol, compared to the no decontamination control. Further, combined dry and wet decontamination resulted in lower recovery of simulant when compared to either dry or wet decontamination alone. Irrespective of decontamination protocol, significantly more simulant remained on the shoulders compared to either the arms or legs, suggesting that improvised decontamination procedures are less effective for difficult to reach areas of the body. There was no effect of decontamination on excreted MeS in urine over 24 hours. Overall, findings indicate that improvised decontamination is an effective means of rapidly removing contaminants from skin, and combinations of improvised approaches can increase effectiveness in the early stages of decontamination and in the absence of specialist resources at an incident scene. However, the variable control and consistency of improvised decontamination techniques means that further intervention is likely to be needed, particularly for less accessible areas of the body

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

Effects of nicotine and E-cigarette fluids on cytochromes P450 in hCMEC/D3 blood-brain barrier cell line

Introduction Electronic cigarettes (EC) represent a safer alternative to tobacco, however, there is limited information on adverse health effects, especially after long term use. Among potential harmful constituents of EC aerosols nicotine is the major addictive chemical and is a precursor for carcinogenic tobacco-specific nitrosamines (TSNAs). Multiple studies have highlighted the ability of nicotine to compromise blood brain barrier (BBB) integrity, altering transport and receptor systems. One knowledge gap is the effect of e-fluids on enzymes responsible for metabolism of toxicants including carcinogens, Therefore, the aim of this study was to examine the effect of nicotine and e-fluid on the expression of cytochrome P450 enzymes (CYPs) in an in vitro model of human BBB, the hCMEC/D3 cell line. Methods The hCMEC/D3 cells were used to investigate time and dose-dependent responses of nicotine or e-fluid and EC aerosol condensate (normalised to nicotine concentration). High quality RNA was extracted and analysed by qRT-PCR for the expression of genes encoding enzymes involved in nicotine metabolism and bioactivation of procarcinogens (CYP1A1, CYP1A2, CYP2A6, CYP2E1, CYP2A13, CYP3A4) and recently described extrahepatic CYP isoforms (CYP2U1 and CYP2S1), which are highly expressed in BBB. Results qRT-PCR results were normalised using UBC reference gene and expressed as a fold change between non treated and treated cells (n=3, p<0.05). Initial analyses revealed a time-dependent increase in mRNA expression levels of CYP2A6, CYP2U1, CYP2E1 and CYP2S1 following exposures with the highest fold change values after 24h. There was no expression of CYP3A4, CYP1A2 or CYP2A13 in hCMEC/D3 cells. Conclusions Significant induction of mRNA expression for CYP2A6, CYP2E1, CYP1A1 and CYP2S1 following treatment with nicotine and e-fluid, suggests that BBB may play an active role in nicotine metabolism and possibly contribute to the bioactivation of procarcinogens. Funding Funded by European Commission Horizon 2020 programme

AN IMPROVED NON-TARGET ANALYSIS AND SUSPECT SCREENING WORKFLOW FOR ORGANIC ACID CONTAMINANTS IN DRINKING WATER

A novel and generalisable analytical workflow for non-target analysis (NTA) and suspect screening (SS) of potentially toxic organic acids in drinking water is presented, featuring selective extraction by silica-based strong anion exchange solid-phase extraction (SAX-SPE), mixed-mode liquid chromatography-high resolution mass spectrometric (LC-HRMS) analysis, non-targeted peak detection, features reduction and SS. To achieve this, a selection of 23 structurally diverse compounds with a broad range of polarities were evaluated. Importantly, the novel introduction of an elution solvent containing ammonium bicarbonate extended the current applicability of SAX-SPE for strong acids and subsequent mass spectrometry analysis. This new method performed with consistently higher recovery (88 ± 7 % at 500 ng L-1), improved selectivity and lower matrix interference (mean = 12%) over a generic mixed-mode weak anion exchange SPE method. In addition, a novel filter for reducing full-scan features from fulvic and humic acids was successfully introduced, reducing workload and potential for false positives. The workflow was then applied to NTA/SS of 10 London municipal drinking water samples, allowing the identification of 22 confirmed substances. Several poorly investigated and potentially harmful compounds were found. In particular, predicted mutagenicity and occurrence frequency indicated the need for further investigation of halogenated hydroxy-cyclopentene-diones (HCDs) and dibromomethanesulfonic acid in drinking water. Overall, this approach demonstrated that employing some selectivity for general molecular properties in NTA overall helped shortlist suspect and potentially toxic chemical contaminants with higher confidence, in this case for organic acids

The presence of tobacco specific nitrosamines in the urine and saliva of cigarette users transitioning to electronic cigarettes

Introduction The aim of this study was to quantify levels of carcinogenic tobacco specific nitrosamines (TSNAs) in human volunteers transitioning from tobacco use to electronic cigarettes (EC). ECs have increased in popularity, with consumers using ECs to aid with smoking cessation, reduce cigarette consumption, or to minimise withdrawal symptoms when smoking but not vaping is prohibited. There has been little investigation into the long term health impacts of ECs, but they are generally considered less toxic than conventional tobacco cigarettes. This is due to the absence or decreased levels of harmful chemicals commonly found in tobacco cigarettes. However, some studies have shown the presence of traces of TSNAs in e-liquid, and the endogenous nitrosation of nicotine to TSNAs in nicotine replacement therapies (NRT). These TSNAs include NNK, NNN, and NNAL, which are potent oesophageal and pulmonary carcinogens. Therefore, inhalation of these compounds may provide an added risk to the use of ECs, when compared to other NRT products. Methods Biofluids have been analysed for TSNAs in the urine and saliva of heavy smokers (>10 cigarettes/day) who quit and transition to EC use for 28 days. A solid phase extraction method using TSNA specific molecular imprinted polymers was used to concentrate samples, which were subsequently analysed using UHPLC-ESI-HRMS. Results Analysis of longitudinal urine and saliva samples (n=13) has shown a decrease in TSNA levels over the period of transition from tobacco use to EC only use. Conclusions The findings are consistent with the notion that substituting conventional cigarettes with ECs significantly lowers exposure to carcinogenic TSNAs. Further work is needed to determine whether TSNAs present in urine and saliva represent continued low level exposure to TSNAs as contaminants in EC or markers of nitrosation. Funding This work is funded by Horizon 2020, and Public Health Englan