Control banding tools for occupational exposure assessment of nanomaterials - Ready for use in a regulatory context?

AbstractThe development, production and application of engineered nanomaterials are becoming more and more widespread. Because researchers, developers and industrial workers are the first in line to be exposed to potentially hazardous nanomaterials, appropriate occupational exposure assessment is a key area of concern. Therefore, a number of Control Banding (CB)-based tools have been developed in order to assess and manage the potential risks associated with occupational exposure to nanomaterials.In this paper we provide a comparative analysis of different nanomaterial-specific types of control-banding/risk prioritization tools (the Control Banding Nanotool, IVAM Technical Guidance, Stoffenmanager Nano, ANSES CB Tool, NanoSafer, and the Precautionary Matrix) in order to evaluate their use-domains; types, extent, use and availability of input parameters; their output format; and finally their potential use and maturity in regard to meeting the minimum requirements for occupational exposure assessment under REACH and the conceptual source-transmission-receptor model by Schneider et al. (2011). This was done through an analysis including a literature review and use of the tools.It was found that the tools were developed for different purposes, with different application domains and inclusion criteria. The exposure assessments and derived risk levels are based on different concepts and assumptions and outputs in different formats. The use of requested input parameters for exposure assessment differ greatly among the tools. Therefore, direct inter-comparison and combination of the different models into a larger holistic framework is not immediately possible.Harmonization of input parameters and output could allow establishment of an exposure assessment framework with different levels of information requirements

Exposure Models for REACH and Occupational Safety and Health Regulations

Model tools for estimating hazardous substance exposure are an accepted part of regulatory risk assessments in Europe, and models underpin control banding tools used to help manage chemicals in workplaces. Of necessity the models are simplified abstractions of real-life working situations that aim to capture the essence of the scenario to give estimates of actual exposures with an appropriate margin of safety. The basis for existing inhalation exposure assessment tools has recently been discussed by some scientists who have argued for the use of more complex models. In our opinion, the currently accepted tools are documented to be the most robust way for workplace health and safety practitioners and others to estimate inhalation exposure. However, we recognise that it is important to continue the scientific development of exposure modelling to further elaborate and improve the existing methodologies

Lung inflammation and genotoxicity following pulmonary exposure to nanoparticles in ApoE-/- mice

<p>Abstract</p> <p>Background</p> <p>The toxic and inflammatory potential of 5 different types of nanoparticles were studied in a sensitive model for pulmonary effects in apolipoprotein E knockout mice (ApoE^-/-). We studied the effects instillation or inhalation Printex 90 of carbon black (CB) and compared CB instillation in ApoE-/- and C57 mice. Three and 24 h after pulmonary exposure, inflammation was assessed by mRNA levels of cytokines in lung tissue, cell composition, genotoxicity, protein and lactate dehydrogenase activity in broncho-alveolar lavage (BAL) fluid.</p> <p>Results</p> <p>Firstly, we found that intratracheal instillation of CB caused far more pulmonary toxicity in ApoE^-/-mice than in C57 mice. Secondly, we showed that instillation of CB was more toxic than inhalation of a presumed similar dose with respect to inflammation in the lungs of ApoE^-/-mice. Thirdly, we compared effects of instillation in ApoE^-/-mice of three carbonaceous particles; CB, fullerenes C₆₀(C₆₀) and single walled carbon nanotubes (SWCNT) as well as gold particles and quantum dots (QDs). Characterization of the instillation media revealed that all particles were delivered as agglomerates and aggregates. Significant increases in <it>Il-6, Mip-2 </it>and <it>Mcp-1 </it>mRNA were detected in lung tissue, 3 h and 24 h following instillation of SWCNT, CB and QDs. DNA damage in BAL cells, the fraction of neutrophils in BAL cells and protein in BAL fluid increased statistically significantly. Gold and C₆₀particles caused much weaker inflammatory responses.</p> <p>Conclusion</p> <p>Our data suggest that ApoE^-/-model is sensitive for evaluating particle induced inflammation. Overall QDs had greatest effects followed by CB and SWCNT with C₆₀and gold being least inflammatory and DNA-damaging. However the gold was used at a much lower mass dose than the other particles. The strong effects of QDs were likely due to Cd release. The surface area of the instilled dose correlated well the inflammatory response for low toxicity particles.</p

First order risk assessment for nanoparticle inhalation exposure during injection molding of polypropylene composites and production of tungsten-carbide-cobalt fine powder based upon pulmonary inflammation and surface area dose

AbstractInhalation exposure to low toxicity and biodurable particles has shown to induce polymorphonuclear neutrophilia (PMN) in the lungs, which is a strong indicator for lung inflammation. Recently, Schmid and Stoeger (2016; http://dx.doi.org/10.1016/j.jaerosci.2015.12.006) reviewed mice and rat intratracheal instillation studies and assessed the relation between particles dry powder BET surface area dose and PMN influx for granular biodurable particles (GBPs) and transition metal oxides. In this study, we measured workers alveolar lung deposited surface area (LDSA) concentrations (μm2 cm−3) during injection molding of polypropylene (PP) car bumpers and production of tungsten-carbide-cobalt (WCCo) fine grade powder using diffusion chargers. First order risk assessment was performed by comparing the doses calculated from measured LDSA concentrations during an 8-h work day with the NOEL1/100, the one hundredth of no observed effect level, assigned for GBPs (0.11cm2g−1) and transition metal oxide particles (9×10−3cm2g−1). During the injection molding of PP car bumpers, LDSA concentrations varied from 23 to 39.8μm2cm−3. During 8-h exposure PP, particle doses were at a maximum of 1.4×10−3cm2g−1, which was a factor 100 lower compared to the NOEL1/100 assigned for GBPs. In the WCCo fine powder production plant, the LDSA concentrations were below 18.7μm2cm−3, which corresponds to the 8-h dose of 2.7×10−3cm2g−1. This is 3 times lower than the NOEL1/100 assigned for transition metal oxide particles. The LDSA concentrations were generally low compared to urban background levels of 44.2μm2cm−3 in European cities

First order risk assessment for nanoparticle inhalation exposure during injection molding of polypropylene composites and production of tungsten-carbide-cobalt fine powder based upon pulmonary inflammation and surface area dose

AbstractInhalation exposure to low toxicity and biodurable particles has shown to induce polymorphonuclear neutrophilia (PMN) in the lungs, which is a strong indicator for lung inflammation. Recently, Schmid and Stoeger (2016; http://dx.doi.org/10.1016/j.jaerosci.2015.12.006) reviewed mice and rat intratracheal instillation studies and assessed the relation between particles dry powder BET surface area dose and PMN influx for granular biodurable particles (GBPs) and transition metal oxides. In this study, we measured workers alveolar lung deposited surface area (LDSA) concentrations (μm2 cm−3) during injection molding of polypropylene (PP) car bumpers and production of tungsten-carbide-cobalt (WCCo) fine grade powder using diffusion chargers. First order risk assessment was performed by comparing the doses calculated from measured LDSA concentrations during an 8-h work day with the NOEL1/100, the one hundredth of no observed effect level, assigned for GBPs (0.11cm2g−1) and transition metal oxide particles (9×10−3cm2g−1). During the injection molding of PP car bumpers, LDSA concentrations varied from 23 to 39.8μm2cm−3. During 8-h exposure PP, particle doses were at a maximum of 1.4×10−3cm2g−1, which was a factor 100 lower compared to the NOEL1/100 assigned for GBPs. In the WCCo fine powder production plant, the LDSA concentrations were below 18.7μm2cm−3, which corresponds to the 8-h dose of 2.7×10−3cm2g−1. This is 3 times lower than the NOEL1/100 assigned for transition metal oxide particles. The LDSA concentrations were generally low compared to urban background levels of 44.2μm2cm−3 in European cities