bluuebunny/crossref_metadata_2025 huggingface dataset:
21 Toxicity of Aircraft Engine Emissions in Calu-3 Human Cells in Air-Liquid Interface Condition.
Authors: Melzi Gloria , van Triel Jos , Gerlofs-Nijland Miriam , Cassee Flemming R
Published: May 2023

Particulate Matter (PM) emissions from aircraft engines adversely affect air quality around airports, contributing to public health concerns for airport workers and neighbouring communities.  In this research, PM was collected from the exhaust of turbine engine after combustion of various types of aircraft fuels, including conventional fuel types Jet A and Jet A1, and more sustainable alternatives with relative low levels of aromatics. PM samples’ toxicity was studied in vitro by air-liquid interface (ALI) exposure of Calu-3 cells in monoculture and co-culture with macrophages (differentiated THP-1 cells). Cells were exposed to PM suspensions (250 µg/mL) using a cloud-based ALI exposure system and analysed 24-hours after exposure. DNA damage was detected through Comet assay in cells exposed to Jet A and Jet A1 samples in absence of cytotoxicity; co-incubation with endonucleases-III and formamidopyrimidine-DNA glycosylase showed that this was not associated with oxidation of DNA bases. Real-Time PCR was performed to investigate the expression profile of genes involved in oxidative stress and DNA repair pathways. Heme Oxygenase 1 gene, Mucin 5AC, and Angiotensin-Converting Enzyme 2 were modulated in the same samples where DNA damage was present. No differences were shown in the pro-inflammatory interleukine-8 secretion among the samples. Most of the PM samples generated using jet fuel with high content of aromatic compounds induced enhanced genotoxicity, suggesting that strategies lowering aromatic content may also result in less toxic PM emissions.  

Funded by Horizon2020 – Research of Aviation PM Technologies, mOdelling and Regulation (RAPTOR), grant number 863969.
27 Acute and Chronic Effects on Inflammatory Markers by Quartz and Particle Exposure in the Iron Foundry Environment
Authors: Hedbrant Alexander , Engström Christopher , Andersson Lena , Eklund Daniel , Westberg Håkan , Persson Alexander , Särndahl Eva
Published: May 2023

Inflammation is a central mechanism in the aetiology of particulate matter (PM)-associated diseases, including cardiovascular diseases (CVD). Both acute inflammatory events and chronic low-grade inflammation due to exposure contribute to adverse health effects of exposure. The aim of the current study was to determine if current exposure levels to respirable quartz or dust at Swedish iron foundries induce acute or chronic systemic inflammatory responses, using biomarkers broadly classified into three groups; 1) general markers of inflammation, 2) novel inflammatory markers of CVD, and 3) NLRP3 inflammasome-related markers. Exposure to respirable dust and quartz was determined during a workday in 40 iron foundry workers, and blood samples were collected before and after workshift. The sampling procedure was repeated approximately three weeks later. To determine acute effects of exposure, the over-shift difference in biomarker levels were studied, whereas to study chronic effects, the average morning sample biomarker levels were correlated to the average exposure levels of the two sampling occasions. We found that biomarkers of the NLRP3 inflammasome correlated to quartz exposure, including acute and chronic effects on ex vivo caspase-1 activation in monocytes, acute effects on plasma levels of IL-18, and chronic effects on IL-1Ra plasma levels. Our results suggest that the present exposure levels to respirable quartz in the Swedish iron foundries, which were below the Swedish occupational limits, may trigger inflammasome activation in the exposed workers.
44 Dual Proteomic Exploration of the Mechanisms Underlying Brake Dust-Induced Impairment of Phagocytic Capacity in Macrophages
Authors: Selley Liza , Franco Catarina , Martin Maria Guerra , Morone Nobuhiro , Purves Jo , Morrissey Julie , MacFarlane Marion
Published: May 2023

Exposure to brake abrasion dust (BAD) reduces the phagocytic capacity of macrophages, possibly contributing to increased risk of airway infections in polluted regions. The mechanisms that underlie this toxicity remain to be characterised and, considering that pre-exposure of respiratory bacteria to alternative traffic-related particulates enhances their dissemination into the lungs of mice, may include changes in the virulence of pathogens themselves. Dual proteomic screening (TMT-labelled UPLC-MS) was performed for RAW 264.7 monocyte-derived macrophages and S.aureus (USA300) following 24h exposures to BAD (0-16 ug/ml). In S.aureus, expression of agr-regulated, anti-leukocytic virulence factors (lipases, staphopains, hemolysins) increased in a dose-dependent manner as well as proteins required for epithelial invasion (serine proteases) and antibiotic resistance. RAW 264.7 exhibited a predominantly adaptive response following exposures, enhancing expression of proteins required for metal homeostasis, NFkB-mediated inflammation and endosomal maturation. However, disrupted expression of proteins required for electron transport chain activity and Fe-S cluster synthesis accompanied significant dose-dependent reductions in ATP production (60-82%, p< 0.001) while transition electron microscopy (TEM) detected disrupted mitochondrial membrane morphology. TEM also identified reductions in pseudopodia length in exposed macrophages (54% shorter than control, p< 0.05), highlighting a mechanism by which BAD exposure may decrease the incidence of host-pathogen interactions. These data highlight dual mechanisms by which BAD emissions could impair bacterial phagocytosis and enhance susceptibility to airway infections.  Through avoidance and suppression of host anti-microbial mechanisms by the bacteria and, as actin polymerisation depends on ATP availability, loss of mitochondrial function and downstream pseudopodia projection in macrophages.
47 Safe-by-Design Advanced Materials: A case Study on Paint Formulation
Authors: Shandilya Neeraj , Isaxon Christina , Persson Michael , Persson Daniel , Moerman Marcel , Hongisto Vesa , Ledwith Rico , Saccardo Angela , Meldrum Kirsty , Clift Martin J D , Fransman Wouter
Published: May 2023

Paint formulations are complex mixtures of both dissolved and particulate components, both organic and inorganic. Amorphous silica nanoparticles are included to make the paint layer dirt-repellent. Over entire life cycle of the paints containing such silica nanoparticles, however, their complex multicomponent composition may raise several concerns as to their hazard when exposed to humans and environment, notably due to the potential release of the incorporated nano-objects. To mitigate such concerns, several Safe-by-Design target specifications can be performed to provide revised/modified paint formulations with reduced potential risk. Within EU H2020 funded project, HARMLESS (grant agreement 953183), a specific industrial case study focuses on worker exposure measurement at the industrial production site of silane modified silica nanoparticles and consumer exposure measurement during sanding of the painted surfaces containing such silica nanoparticles. First results indicate that the tested paint samples (with and without silica nanoparticles) have strong tendencies to generate airborne nano-objects during their sanding. However, the fraction of silica in the overall chemical composition of the airborne nano-objects is currently being investigated. A fraction of the dust generated during the paint sanding is being analysed for its hazard via advanced in vitro approaches combined with a battery of toxicological endpoint analyses. Based on the results, if the exposure concentration of silica nanoparticles is found to be exceeding its nano reference value (i.e. 40,000 cm-3 TWA) and exhibits deleterious biological impact, the size and surface of silica nanoparticles will be modulated accordingly by keeping an optimum balance between their functionality and risk
50 Human Hazard Assessment of Nanomaterials: Supporting Risk Decision Making Through Interlaboratory Trial Data
Authors: Burgum Michael , Yamani Naouale , Longhin Eleonora , Mariussen Espen , Rundén-Pran Elise , Sosnowska Anita , Puzyn Tomasz , Clift Martin , Dusinska Maria , Doak Shareen
Published: May 2023

The prevalent application of engineered nanomaterials (ENMs) has led to an extensive effort to develop tools facilitating their risk assessment and management. This interlaboratory trial (encompassing two laboratories) sought to investigate the genotoxic impact of ENMs using the hypoxanthine phosphoribosyltransferase (HPRT) forward mutation assay and in vitro cytokinesis-blocked micronucleus (CBMN) assay, utilising harmonised protocols. In the CBMN assay, human lymphoblast (TK6) cells were exposed to zinc oxide (ZnO), titanium dioxide (TiO2) and tungsten carbide-cobalt (WC/Co) for 24-hours after which 1000 binucleated cells were scored for micronuclei (n=2). For the HPRT assay, TK6 and mouse fibroblast (V79) cells were exposed to ZnO, TiO2, WC/Co, CuO and Nanocyl-CNTs for 24-hours after which 600 wells were scored for point mutations (n=2). Significant cytotoxicity and micronuclei frequency was reported following ZnO exposure (20µg/ml). Significant micronuclei induction was reported following WC/Co exposures (2-fold over control, 100µg/ml). No significant mutagenicity was detected with ZnO or TiO2; both laboratories observed significant cytotoxicity following exposure to ZnO (20µg/ml; 37% reduction in cell viability). In the second interlaboratory trial CuO induced significant cytotoxicity (36% reduction in viability: 0.5µg/ml), and a 32-fold increase in mutagenicity. The Nanocyl induced a 6-fold increase in mutagenicity. The data generated here has shown good statistical concordance between laboratories and has highlighted a promising route forward in supporting risk decision making for ENMs. The authors would like to acknowledge this research has received funding from the European Union’s Horizon 2020 research and innovation program for the RiskGONE project, grant agreement #814425.
56 Monitoring Diesel Exhaust Particles by Lock-in Thermography
Authors: He Ruiwen , Gunasingam Gowsinth , Petri-Fink Alke , Rothen-Rutishauser Barbara
Published: May 2023

Diesel exhaust particles (DEPs) can deposit onto the respiratory epithelial surface upon inhalation. In vitro exposures of various lung models to DEPs have been performed under the air-liquid interface (ALI) conditions in previous studies, however, methods to quantify DEPs onto/into cells during and after exposure are still challenging and not well established. In our study, a new particle detection system, i.e. lock-in thermography (LIT), was explored. LIT is a heat- sensitive imaging method that applies the light illumination to induce the heat of carbon-based particles for detection. By testing a standard DEPs sample (SRM2975), a positive linear relationship (R2 = 0.98) was established between the thermal emission signals and DEPs levels ranging from 0 to 30 µg/mL, with limit of detection (LOD) at 1.00 µg/mL. Moreover, phototoxicity tests showed that no cytotoxic effects were observed on human lung epithelial (A549) cells upon excitation light wavelength of 525 and 660 nm for 1 – 2 mins. Taken together, it suggests that the LIT can be used for detecting DEPs exposed with A549 cells at the relatively low concentration. Further improvement and optimization of the LIT system are ongoing to evaluate DEPs exposed lung cells.
58 Setting Targets for Particles in Outdoor Air: Advice from the Committee on the Medical Effects of Air Pollutants (Comeap)
Authors: Hansell Anna , Kelly Frank , Walton Heather , Mitsakou Christina , Earl Naomi , Doutsi Artemis , Exley Karen , Gowers Alison
Published: May 2023

The Environment Act (2021) requires the government to set at least one long-term air-quality target, as well as a target for fine particulate matter (PM2.5) air pollution. COMEAP provided independent expert advice to the Department for Environment, Food and Rural Affairs (Defra) to inform the development of targets to reduce both the annual average (mean) concentration of PM2.5 in ambient air and long term population exposures. COMEAP’s advice includes that: a focus on reducing long-term average concentrations of PM2.5 is appropriate evidence indicates that PM2.5 pollution can have harmful effects on people’s health at low concentrations reducing concentrations to, or below, the World Health Organization’s new Air Quality Guideline (5 µg/m3) would benefit public health available studies have not indicated a threshold of effect below which there is no harm reducing exposure of the whole population would achieve the greatest overall public health benefit some individuals or groups are more at risk, but it might be difficult to reflect this in a national targets framework the health benefits of reducing other pollutants, such as nitrogen dioxide and ozone, should not be overlooked. In response to Defra’s evidence report explaining the rationale for its proposed targets, COMEAP: recommended that Defra should consider roles in continuing to improve air quality, even where legally binding targets are met suggested that interim targets would be important to ensure early progress and maximise health benefits stressed the importance of considering inequalities noted that international engagement will be required
63 A Case for Amorphous Silica Nanoparticle Exposure in the Development of Chronic Kidney Disease of Unknown Etiology
Authors: Rogers Keegan , Stem Arthur , Roncal Carlos , Johnson Richard , Brown Jared
Published: May 2023

We have hypothesized that sugarcane burning in developing countries contributes to an endemic kidney pathology in agricultural workers called chronic kidney disease of an unknown etiology (CKDu).  Elemental analysis shows that sugarcane stalks contain a high percentage of amorphous silica (SiO2). Therefore, we hypothesized that burning of sugarcane generates silica nanoparticles (SiNPs) that present an inhalation hazard to these agricultural workers. To determine if SiNPs are present in sugarcane ash and kidney biopsies from agricultural workers, we utilized single particle inductively coupled plasma mass spectrometry and found SiNPs, which ranged in size from 190-212 nm, in sugarcane ash. In a small cohort of CKDu patients from El Salvador and Mexico, we found a significant increase in the number of SiNPs in their kidney biopsies within a similar size range as observed in sugarcane ash. Additionally, Wistar rats exposed to sugarcane ash intranasally for 24 weeks developed focal injury in the tubulointerstitium and glomeruli with deposition of SiNPs in the kidney.  To further determine the cellular effects of SiNPs, we exposed human proximal convoluted tubule (PCT) cells to sugarcane ash, de-silicated ash, or sugarcane ash derived SiNPs. Despite not being directly cytotoxic to PCT cells at 24 hrs, SiNPs were taken up and generated reactive oxygen species. Vimentin staining confirmed PCT cells underwent epithelial-mesenchymal transition (EMT) following treatment with ash or SiNPs but not with de-silicated ash. These findings suggest SiNPs present in sugarcane ash are capable of driving EMT in PCT cells potentially contributing to a CKDu phenotype.
78 Nano Exposure Quantifier (NEQ) - A Quantitative tool for Assessing Exposure in the Workplace
Authors: Franken Remy , Goede Henk , Shandilya Neeraj , Ge Calvin , Kalkman Gino , Otto Marlies , van Venrooij Bart , van Someren Eugene , Fransman Wouter
Published: May 2023

Background

The EU Horizon2020 “safe-by-design for Nano” (SBD4Nano) project aims to develop a tool to assist users in the safe-by-design process and decisions to reduce risk as a result from working with- or using newly developed products containing manufactured nanomaterials (MNs). Therefore, TNO set out to develop an easy-to-use quantitative exposure assessment tool that helps users with different levels of expertise to reduce the exposure from MNs following an integrated Tiered safe-by-design approach.

Method

Based on previous projects, literature, expert knowledge, a Tiered set of model determinants and corresponding calculations were integrated into a conceptual model. Also, an exposure database based on the EU GRACIOUS template was created containing a large set of exposure measurements collected from diverse literature studies. Machine learning was applied to these exposure measurements to validate and refine the model. Lastly, a safe-by-design module was added to assist users modify their material or process design to reduce exposure.

Results

An online tool is realized that will be freely available on https://diamonds.tno.nl/#neq. The NEQ offers a Tiered approach by smartly adapting the questions based on the depth of information the user can provide allowing anywhere between a Tier-1 and a Tier-2 approach. After answering questions, the user is presented an exposure estimate including uncertainty of the current design. The user is guided to enter a new design that reduces the exposure and/or its uncertainty.
90 Graphene – Exposure and Emissions at Two Pilot Plants
Authors: Tinnerberg Håkan , Storsjö Tobias , Isaxon Christina
Published: May 2023

Graphene is a nanomaterial suitable for a wide variety of applications. The industrial production and use of graphene is, hence, increasing rapidly. The main challenge in assessing graphene exposure is that graphene is a carbon structure, making it comparable to look for a needle in a haystack. We have explored the possibility to analyze elemental carbon and black carbon as a measure of personal graphene exposure. Exposure and emission measurements for graphene were conducted at two pilot plants using on- and off-line techniques. One plant produces graphene, up to 10 tons per year, using liquid exfoliation technique. The other plant uses graphene to coat paper in a conventional roll-to-roll process.  The measurements were conducted both stationary (in the emission zone and in the background) and as personal measurements (in the breathing zone of the workers). We have analyzed elemental carbon and black carbon as a measure of the personal exposure. In the emission and background zone we have measured number of particles and lung deposited surface area concentration of particles <300nm, mass concentration, and we have collected samples for electron microscopy analysis. The exposure was in general low, but we identified tasks with an increase emissions. Measurements of elemental carbon is a promising technique for occupational hygienists to find possible exposure to graphene.
112 Use of a Human Bronchial Epithelium Model to Assess the Impact of PM2.5 Exposure on the Severity of Viral Infections
Authors: Chivé Chloé , Martin-Faivre Lydie , Eon-Bertho Alice , Garcia-Verdugo Ignacio , Baeza-Squiban Armelle
Published: May 2023

Epidemiological studies have shown an association between exposure to fine particles (PM2.5) and the severity of respiratory infections such as influenza and COVID-19. PM2.5 and viruses target the bronchial epithelium suggesting that exposure to PM2.5 could make it more susceptible to infections. Our project aims to study the impact of PM2.5 on the severity of influenza virus and decipher the underlying mechanisms. We used a human bronchial epithelium grown at air-liquid interface (ALI) and characterised its responses to a single 24h exposure to PM2.5 at ALI at 5, 10 or 20 µg/cm². Particles induced the expression of the pro-inflammatory cytokines IL-6 and IL-8 as well as IFN-β showing an impact on the antiviral signaling pathway. When bronchial epithelium is infected with influenza virus (murine H3N2) after 24h exposure to PM2.5, there is an increase in LDH activity in the apical secretome associated with a trend towards increased expression of the viral protein M2 as well as an enhanced release of mediators of the antiviral defense (IL-6, IL-8, RANTES), compared to the non-exposed epithelium. These results suggest that pre-exposure to PM2.5 may increase the severity of viral infection in association with an increase of viral replication which needs to be confirmed subsequently by virus titration. Antiviral signaling is now investigated and the effects of repeated exposures of the bronchial epithelium to PM2.5 on the severity of viral infection are also explored. 

This work is support by the Foundation for Medical Research, French Environment and Energy Management Agency and DIM Qi2.
115 Fibre-Aerogel-Mats for façade Insulation: How to Guide SSbD Development by Screenings?
Authors: Wohlleben Wendel , Battista Veronica Di , Guenter Eva , Ribalta Carla , Jensen Keld , Saccardo Angela , Meldrum Kirsty , Clift Martin , Baun Anders , Demokritou Philip
Published: May 2023

The HARMLESS project focusses upon assessment approaches to support Safe-and-Sustainable-by-Design (SSbD) development of advanced materials (AdMa). Case studies comprise several industry sectors. Specifically for the construction sector we study façade insulation by fibre-aerogel-mats. Beyond the relatively simpler mono-component organic aerogels presented earlier (Keller et al. 2021), here we deal with multi-component materials: Glass fibers provide structural integrity for the silica-based aerogel that provides the thermal insulation performance, though is coated by organosilane as a hydrophobizing agent to prevent moisture uptake. Optionally, an additional inorganic coating can be applied to enhance mechanical stability. Here we explored this wide SSbD design space by four industrially relevant SSbD-versions of fibre-aerogel-mats; these were ranked and compared against each other as well as conventional insulation material (i.e. stone wool). We assessed the release by performing several typical occupational operations under clean-air conditions within a laboratory setting. Up to 106/ccm particles are released, with respirable aerodynamic diameters. We collected the dust and assessed the structure and behavior with respect to its biological reactivity and biodissolution, focusing on the screening and ranking of inhalation hazards. The data on exposure and hazard was complemented by data on functionality in the intended use, where all SSbD versions performed significantly better than the conventional alternative. The new data refines the risk screening and categorisation schemes for advanced materials, including Early4AdMa (RIVM 2022), AdmGRID (Kennedy et al. 2019), InnoMat.Life (Wohlleben et al. 2022) and an environmental risk screening (Arvidsson et al. 2022).
119 Differential Alveolar Toxicity of Exhaust and Non-Exhaust Fine Particulate Matter
Authors: Parkin James , Dean Lareb S N , Raj Helen S V , Cooper Dawn , Ridley Robert , Davies Elizabeth R , Conforti Franco , Bell Joseph A , Wang Yihua , Downward Julian , Cooper Matthew J , Cassee Flemming R , Davies Donna E , Cook Richard , Loxham Matthew
Published: May 2023

Introduction

Airborne fine particulate matter (diameter <2.5μm; PM2.5) is a leading risk factor for ill health and premature death. Road vehicle technology is decreasing exhaust-derived PM emissions but poorly characterised, unregulated non-exhaust PM persists. This study aimed to characterise the toxicology of brakewear PM2.5 (BWPM) from 4 brakepad types, and roadwear PM, compared to diesel exhaust PM2.5 (DEP).

Methods

An alveolar type-II epithelial cell line (ATIIER:KRASv12) was exposed to 3.9-31.6µg/cm2 PM2.5 generated from 4 brake pad types (low-metallic/semi-metallic/non-asbestos organic [NAO]/ceramic), roadwear, or DEP for 2-24h. PM composition was determined by ICP-MS, cytotoxicity by LDH and MTT assays, cytokine release by ELISA, gene expression by RT-qPCR and RNA-Seq, and protein expression by western blot.

Results

NAO and ceramic BWPM, enriched in copper and zirconium, exerted greatest increases in cytotoxicity, cytokine release (IL-6: NAO 26-fold, ceramic 20-fold; p<0.05), and oxidative stress-related (HMOX1 – NAO 28-fold, ceramic 26-fold, p<0.001) and metal homeostasis genes (MT1G: NAO 197-fold, ceramic 183-fold; p<0.001), consistently greater than roadwear PM or DEP. Amelioration by copper-chelating tetraethylenepentamine implicated BWPM copper. RNA-Seq showed NAO and ceramic BWPM induced most differentially expressed genes vs. control, related to inflammatory, oxidative stress, heat-shock, and hypoxia responses. Effects on hypoxia signalling were confirmed through HIF1α western blot and HIF-signalling reporter assay.  

Conclusions

NAO and ceramic BWPM were the most potent across multiple endpoints. Future work will study the relevance of HIF-related responses, which have been implicated in fibrotic lung disease. Understanding source-dependent toxicity may facilitate manufacturing- and healthcare-related mitigation of PM toxicity.
125 Effect of Multi-Walled Carbon Nanotube Exposure on wild type and p53+/- Rat Lungs
Authors: Barthel Hélène , Sébillaud Sylvie , Lorcin Mylène , Wolff Henrik , Viton Stéphane , Cosnier Frédéric , Gaté Laurent , Seidel Carole
Published: May 2023

Carbon nanotubes (CNTs) are nanomaterials that can be inhaled by employees during production or handling. One CNT, Mitsui-7 (MWNT-7), has been classified by the International Agency for Research on Cancer as “possibly carcinogenic to humans”. In addition, there is a proposal coming from the risk assessment committee of ECHA to classify all fibres with dimension’s compatible with the “Fibre Paradigm” (FP), as carcinogenic. However, there is a lack of clarity regarding the fibres that do not fill the criteria of the FP. In this study, we compared Mitsui-7, compatible with the FP criteria, to a CNT, NM-403, too short and thin to fill this principle. We exposed Sprague Dawley female rats deficient for p53 (GMO), or wild type (WT), by intratracheal instillation to these two CNTs. The animals (GMO and WT) were exposed once a week for 4 consecutive weeks to 0.25 mg/rat of CNT and were sacrificed 3 days and 8 months after the last instillation. Exposure to both CNTs induced acute lung inflammation, which persisted after 8 months in the lungs of rats only exposed to NM-403. On the top of a persistent inflammation, NM-403 also stimulated hyperplasic changes in the rat lungs, which can be considered as a precursor stage for neoplasia. However, no adenoma nor carcinoma was detected. The hyperplasia was significantly more pronounced in the GMO rats. The results suggest that CNT not filling the criteria of the FP can cause persistent inflammation and pre-neoplastic changes. Their safety should be addressed with caution.
126 Emission and Exposure Characterization During Metal Waste Recycling
Authors: Isaxon Christina , Lovén Karin , Ahlberg Erik , Bermeo Marie , Messing Maria , Kåredal Monica , Hedmer Maria , Rissler Jenny
Published: May 2023

Waste of electrical and electronic equipment (WEEE) is one of the fastest-growing waste streams in the EU. The airborne occupational and environmental exposures generated by this waste handling are poorly quantified, and the growing use of nanomaterials in electronics adds to the uncertainty of risk assessment. Emission and personal exposure measurements were carried out during industrial recycling for three different metal waste flows: WEEE, metal scrap and cables. Size distributions and number-, mass- and lung deposited surface area concentrations were assessed by on-line techniques, and filter samples were collected for gravimetric analyses, metal content, and electron microscopy. Samples for elemental analyses with Particle Induced X-ray Emission (PIXE) was collected by a 12-stage low-pressure impactor . Additionally, low-cost sensors were deployed for long term monitoring. By number, the size distributions from all three flows were heavily dominated by particles <100 nm. Electron microscopy showed that there are many different elements in the same particle and that the composition of different particles vary considerably. Abundant elements, according to ICP-MS, were Fe, Al, Zn, and Cu, but Pb, Mn, Ba, and Co were also detected. PIXE analysis showed that the chemical composition indeed is different in different particle sizes, with e.g. Cr almost exclusively being present in particles < 200 nm. Low-cost sensors, not previously used for monitoring in highly polluted industrial settings, functioned well after 30 days. This study shows that detailed particle characterization is crucial for understanding of today’s and tomorrow’s waste recycling exposures, and as input to future toxicological assessments.
142 Short-Term Exposure to Nanomaterials and Effect Biomarkers at Local and Systemic Levels: dose-Response Modelling Results from the Nanoexplore Project
Authors: Canu Irina Guseva , Hemmendinger Maud , Squillacioti Giulia , Ghelli Federica , Charreau Thomas , Sauvain Jean-Jacques , Suarez Guillaume , Hopf Nancy B , Progiou Athena , Fito Carlos , Bergamaschi Enrico
Published: May 2023

We aimed at analyzing dose-response relationship between occupational exposure to a mixture of nanomaterials (NMs) and effect biomarkers measured according to the NanoExplore protocol in  exhaled breath condensate (EBC, local pulmonary level)) and urine (systemic level) of 141 workers. Two exposure metrics: particle number concentration (PNC) and lung deposited surface area (LDSA) were monitored using DiSCMini for 2-4 8h-workshifts. Biological samples were collected twice, before and after exposure monitoring. We assumed that current or short-term exposure to NMs is associated in a linear dose-response manner to the effect biomarker concentration. We analyzed each biomarker separately, using the multilevel mixed-effects interval regression models to properly manage the biomarker concentrations the LOD or in the interval between the LOD and the limit of quantification. We used directed acyclic graphs to identify all potential confounders: age, smoking status, medication status, and study center. Center and the participant’s ID were modeled as random effect variables. For IL-10, IL-1β and TNF-α in EBC we observed consistent positive dose-response relationships with both PNC and LDSA. For urinary Total Antioxidant Power the relationship was consistently negative. For MDA, KL-6, hs-CRP or NOTyr in EBC and urinary MDA and 8-Isoprostane, no relationship was found. These results suggest an activation of the innate immune response rather than oxidative stress as the main effect of the mixture of NM investigated. This study offers new insights into the dose-response relationship between exposure to NMs and possible indicators of early and long-term biological alterations in the cohort of recruited workers.
149 Chronic Immunotoxicity of Multi-Walled Carbon Nanotubes on Macrophages via MMP-12
Authors: Ishimaru Naozumi , Otsuka Kunihiro , Tsunematsu Takaaki , Taquahashi Yuhji , Kanno Jun
Published: May 2023

Background

The toxicological effects of nanomaterials, such as multi-walled carbon nanotubes (MWCNTs), on the immune system are considerably understood. However, the precise relationship between long-term exposure to MWCNTs and chronic inflammation remains unclear.  

Methods and Finding

In this study, exposure to Taquann-treated MWCNTs (T-CNTs) was performed using aerosols generated in an inhalation chamber. At 12 months after T-CNT exposure, alveolar inflammation with macrophage accumulation and hypertrophy of the alveolar walls were observed. The fibrotic lesions were enhanced by T-CNT exposure. The cell surface phenotype of macrophages in the bronchoalveolar lavage fluid was shifted to the M1 macrophage phenotype. In addition, the alveolar macrophages of T-CNT-exposed mice produced matrix metalloprotinase-12 (MMP-12). By contrast, a mouse model of chronic peritonitis was also established using intraperitoneal injection of T-CNTs with high dispersion efficiency. Chronic peritonitis with fibrosis was observed in T-CNT-injected mice, but not in Taquann-treated TiO2-injected mice. In vivo and in vitro experiments showed that MMP-12 of macrophages was upregulated by T-CNT to enhance fibroblast activation and profibrotic molecule expression in fibroblasts. In addition, T-CNT-induced peritonitis reduced MMP-12 expression in Nfκb1−/− mice, suggesting that MMP-12-producing macrophages play a key role in chronic inflammation due to T-CNT exposure though NF-κB activation.

Conclusion

These results using the two models suggest that T-MWCNT exposure promoted chronic inflammation and fibrotic lesion formation in profibrotic macrophages via MMP12 for prolonged periods. The results of this study could be helpful in understanding the molecular toxicity of nanomaterial and chronic inflammation.
150 The Innomat.Life Extended Fibre Human Risk Banding Scheme
Authors: Broßell Dirk , Wolf Sebastian , Dziurowitz Nico , Thim Carmen , Meyer-Plath Asmus , Plitzko Sabine , Wiemann Martin , Pfohl Patrizia Marie , Wohlleben Wendel , Stahlmecke Burkhard , Wolf Carmen , Haase Andrea
Published: May 2023

High aspect ratio materials (HARMs) like multi-walled carbon nanotubes (MWCNTs) show material properties that enable innovative applications but also raise concerns about harmful effects to humans due to their asbestos-like pathogenicity. The fibre-pathological paradigm was established for asbestos and other HARM, linking fibre-specific adverse effects to certain material properties such as fibre length, respirability and bio-persistence. A new risk banding scheme for such hazard- and exposure-related properties is introduced. For each relevant property, we defined descriptors and developed/validated methods for their measurement. Based on results from studies conducted in the project or obtained from literature, we defined quantitative band limits. While the fibre-pathological paradigm acted as a starting point, observations of in vitro effect of nanofibers motivated us to incorporate additional properties. Studying macrophage-fibre interactions led us to highlight the importance of the flexural rigidity of fibres for their uptake by macrophages. Also, the bundling of thin constituent fibres was recognized as a mechanism possibly generating less flexible and, therefore, more harmful inhalable particles with high aspect ratio from harmless precursors. Transformation dynamics of fibres in fluids like the phagolysosomal medium were investigated as well to gain a better understanding about fibre bio-durability. Overall, the risk for humans exposed to HARMs is described by the risk banding scheme in which property bands relevant for the hazard potential were juxtaposed to the respective exposure potential. We present results for a selection of HARMs including multiple MWCNTs with varying properties, TiO2 fibres, SiC whiskers, as well as silver and copper nanowires.
154 Toward a General Approach to Risk Assessment of Naturally Occurring Asbestos and Asbestos-Like Minerals: the case of Fibrous Antigorite
Authors: Turci Francesco , Petriglieri Jasmine Rita , Barale Luca , Gazzano Elena , Aldieri Elisabetta , Tomatis Maura , Ballirano Paolo , Piana Fabrizio , Campopiano Antonella , Pacella Alessandro
Published: May 2023

The natural occurrence of asbestos and asbestos-like minerals (NOA) poses a risk to the environment and human health, notably when natural processes and anthropic activities promote fibre dispersion. Hundreds of potentially hazardous elongated mineral particles (EMPs, NIOSH 2011 definition) exist, and their toxicological profile is often unknown. We aim here to define a general approach, from field analysis to nano-structural investigation, to assess whether a fibrous mineral occurring in a specific site could pose a risk to human health. To evaluate the hazard associated with NOA, a multi-scale and multi-analytical integrated approach was adopted. Specifically, the geological factors that control the occurrence and distribution of NOA on site, and the mechanisms of formation and liberation of airborne fibres were investigated. In parallel, we explored the key bulk and surface properties of several natural mineral fibres and defined crystallographic, chemical, and morphological aspects that should be considered during hazard assessment. Also, the effect of standardized mechanical stress was used to simulate variation on morphometric parameters of investigated minerals and allowed us to quantitatively evaluate the potency to generate inhalable fibres. This property was connected with the mineral characteristic and the rock fabric. Isolated fibre specimens were used to assess solubility in simulated body fluids, surface reactivity, and toxicological endpoints in vitro and in vivo. Taken together, these findings allowed us to build a multidimensional description of the hazard parameters of a mineral fibre and paved the way for a science-based risk assessment in an unexplored NOA site.
155 A test Chamber to Quantify Emission Factors for Welding Fumes
Authors: Quecke Emily , Hashisho Zaher , Quemerais Bernadette
Published: May 2023

A conical test chamber was built to quantify emission factors for various types of welding processes. The chamber was built according to American Welding Society (AWS) standard F1.2:2013. Fumes were collected on pre-dried and pre-weighted 293 mm glass fiber filters using a high-volume sampling pump running at approximately 30 cfm. Consumables were weighted before and after welding to calculate the amount of fume emitted per weight of consumable. All the welding was performed by a professional welder. The chamber was calibrated prior to any use to adjust the flowrate inside the chamber. The test chamber was used to calculate emission factors for Shielded Metal Arc Welding process using four different electrodes (E6013, E6011, E7018, E7014) and three different currents for each electrode as fume emission increases with current. Each test was done in triplicates to investigate for variation. Emission factors were calculated by diving the amount of fume on the filters by the weight of consumables used (g/kg). In general test were reproducible with coefficient of variations varying from 0.2 to 18.1% with most variation below 15%. Emission factors were highly dependent on the type of electrode with the lowest values found for E6013 and the highest for E6011. Emission factors increased significantly with increasing current. The chamber works properly and can be used to test other processes such as Gas Metal Arc Welding, Metal Core Arc Welding, Flux Core Arc Welding, as well as Gas Tungsten Arc Welding. Emission factors will also be calculated for metals.
7 Construction and Characterization of a Thermal Spray Coating Aerosol Generator
Authors: Lee Eun Gyung , Afshari Aliakbar , McKinney Walter , Kodali Vamsi K , Friend Sherri , Antonini James M , Virji M Abbas
Published: May 2023

Thermal spray coating (TSC) is a surface treatment process whereby feedstock material is sprayed onto surfaces under pressure where it solidifies and forms a solid coating. In metal TSC processes, large quantities of aerosols, including fine and ultrafine metal particles are generated. However, exposure assessment for TSC is lacking. The goal of this study was to construct a TSC aerosol generation system and to characterize the physicochemical properties of aerosols generated during coating processes. A computer-controlled, automated electric arc wire-TSC aerosol generator system was built in an enclosed room, where a rotary motor rotates a metal feedstock pipe in circular and up-and-down directions to allow even deposition of coating material on the pipe surface. The characteristics of aerosolized particles during spray coating using a stainless-steel wire (PMET 720) showed that: 1) respirable mass concentrations ranged from 142–218 mg/m3 (3 spray shots with each shot of 1-sec during 20-min sampling), 2) diameter of peak particle number concentrations was between 360 nm and 400 nm, 3) mass median aerodynamic diameter determined by an impactor ranged from 290–370 nm, 4) particle morphology was observed to be diverse including chain-like agglomerates and spherical and cylinder-like shapes, and 5) metal composition was 80% iron, 17% chromium, and 3% manganese with trace amounts of nickel and copper. These findings are limited to one wire type and suggests the need for further investigations evaluating various parameters (e.g., wire/powder types, high/low energy, ventilation on/off) to obtain emission rates and recommend control measures.
22 Development of an Integrated Exposure Pathway Model for Health Impact Assessment of Traffic Ultrafine Particles (H2020 Ultrhas-Project)
Authors: Korhonen Antti , Lehtomäki Heli , Rumrich Isabell , Roponen Marjut , Bølling Anette , Aasvang Gunn Marit , Jalava Pasi , Rothen-Rutishauser Barbara , Bucchianico Sebastiano Di , Zimmermann Ralf , Øvrevik Johan , Hänninen Otto
Published: May 2023

Recently, the causal associations between traffic emissions and health effects were strengthened by the systematic reviews by the Health Effects Institute (HEI#23, 2022). According to EuroStat data Europeans spend 87-97% of their time indoors in homes, workplaces, schools and nurseries. Breathing volumes are dominated by the time spent indoors (16 m³ indoors and 1.4 m³ outdoors), even though breathing rates in outdoor environments are higher. This demonstrates the importance of taking into account time activity as well as infiltration to indoor spaces when estimating intake of particles.

The ULTRHAS project aims to link in vitro toxicological evidence for particulate matter to health impact assessments to look specifically into this. An integrated exposure pathway model will consider for different microenvironments, and physical activity patterns to quantify the particle intake in selected gender and age groups. Relative to the commonly applied approach using residential address and corresponding outdoor pollution levels we specifically add handling of (i) infiltration into indoor spaces and (ii) variability in breathing volumes based on physical activities. The model will provide inhalation volumes for selected target populations, to be applied in the intake-DALY estimation of burden of disease parameters in the following phases of the project.
29 Fugitive Emissions from Carbon Dioxide Laser Cutting Activities
Authors: Tsai Candace , Munoz Alejandro , Schmidt Jacob , Suffet Mel
Published: May 2023

Carbon Dioxide laser cutters are used to cut and engrave on various types of materials, including metals, wood, and plastics. Although many are equipped with fume extractors for removing airborne substances generated during laser cutting, gases and particulate matter can be released upon opening the lid after completion. Real-time instruments were utilized to monitor both particulate concentrations and size distributions, while the novel Tsai Diffusion Sampler was used to collect particulate samples on a polycarbonate membrane and TEM grid. Preliminary detection of released gases consisted of the use of gas sampling with Teflon Gas Bags and followed with analysis using Gas Chromatography-Mass Spectrometry (GC-MS). A portable ambient infrared air analyzer was used to quantify the concentrations of the chemicals released by the laser cutting activities. Results of the study found that a significant concentration of particulate matter ranging 15.4 - 86 nm in particle sizes were released each time the laser cutter lid was opened and were observed to gradually increase in concentration for a period of at least 20 minutes after the completion of a cut. The GC-MS gaseous samples primarily contained methyl methacrylate at a low level close to the detection limit of the infrared air analyzer.
43 Particle and VOC Emissions During the Thermal Processing of Plastics to make Filaments for 3D-Printing
Authors: Eden Gunilla Runström , Möller Rickie , Tinnerberg Håkan , Almstrand Ann-Charlotte , Bredberg Anna
Published: May 2023

Introduction

3D-printing is continuing to grow as an industry, which creates a demand for printing material. Studies on 3D-printing have shown that printers emit nanoparticles and VOC, depending on printing method, and some adverse health effects have been reported. Emissions during production of 3D-printer filament is less studied, and interesting as it can be likened to a larger material extrusion printer. 

Materials and methods

Measurements were made at a factory producing 3D-printer filaments, using an array of instruments to characterise the emissions and exposure for the staff. Particle emissions were assessed using condensation particle counters (20nm-1um), DataRAM (0.1-10 um) and a particle sensor (0.35-40 um). VOC emissions and exposure were assessed using Tenax tubes and VOC sensors.  Measurements were performed for 1-2 days, apart from sensors, which were placed at the facility for a full working week, including after a longer break . 

Results

High concentrations of nanoparticles were found in the production rooms (25 000-100 000 pt/ml) and close to the extruder nozzle (100 000-500 000 pt/ml). Levels of nanoparticles were also high in office rooms near production(25 000-50 000 pt/ml). VOC sensors showed the same trend in all rooms, including offices and staff kitchen, indicating spread of emissions from the source and inadequate ventilation. The particle sensor also showed variation over the week in correlation with work performed. 

Conclusion

Production of 3D-printer filaments emit nanoparticles and VOC. Inadequate ventilation can lead to high concentrations of nanoparticles. Sensors were a useful tool to show emission trends.
95 Identifying Physicochemical Properties of Nanomaterials as Potential Drivers of oral Hazard and Their Modulation by safe and Sustainable-by-Design Strategies
Authors: Roriguez-Garraus Adriana , Delpivo Camila , Candalija Ana Maria , Simeone Felice , Vázquez-Campos Socorro , Catalán Julia
Published: May 2023

Throughout their whole life cycle from production to waste disposal, nanomaterials (NMs) and nano-enabled products (NEPs) are in contact with humans by different exposure routes and may induce adverse health effects. After oral exposure they may give rise to local or even systemic toxic effects associated to their dissolution behaviour, intestinal absorption or by being trapped into the gastrointestinal barrier Safe and sustainable-by-design (SSbD) interventions to reduce or mitigate NM/NEP risks along their life cycle have been suggested in the last years. However, no clear physico-chemical (PC) properties modulating the hazard by the oral route have been identified. Based on published practical examples of successful SSbD strategies, key PC properties determining the technical function of the NM in the NEP as well as those modified by the SSbD intervention are identified. In addition, oral IATAs from the GRACIOUS project are used to identify which PC properties could be relevant to determine the fate of NMs/NEPs after oral exposure. A further literature search on the specific NM/NEP may help to unravel the relationships among key PC properties and associated mechanisms of hazards.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 862419.