| 1. |
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| 2. |
- Cronholm, Pontus, et al.
(författare)
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Effect of sonication and serum proteins on copper release from copper nanoparticles and the toxicity towards lung epithelial cells
- 2011
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Ingår i: Nanotoxicology. - : Informa UK Limited. - 1743-5390 .- 1743-5404. ; 5:2, s. 269-281
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Tidskriftsartikel (refereegranskat)abstract
- Different methodological settings can influence particle characteristics and toxicity in nanotoxicology. The aim of this study was to investigate how serum proteins and sonication of Cu nanoparticle suspensions influence the properties of the nanoparticles and toxicological responses on human lung epithelial cells. This was investigated by using methods for particle characterization (photon correlation spectroscopy and TEM) and Cu release (atomic absorption spectroscopy) in combination with assays for analyzing cell toxicity (MTT-, trypan blue- and Comet assay). The results showed that sonication of Cu nanoparticles caused decreased cell viability and increased Cu release compared to non-sonicated particles. Furthermore, serum in the cell medium resulted in less particle agglomeration and increased Cu release compared with medium without serum, but no clear difference in toxicity was detected. Few cells showed intracellular Cu nanoparticles due to fast release/dissolution processes of Cu. In conclusion; sonication can affect the toxicity of nanoparticles.
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| 3. |
- Elihn, Karine, et al.
(författare)
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Cellular Dose of Partly Soluble Cu Particle Aerosols at the Air-Liquid Interface Using an In Vitro Lung Cell Exposure System
- 2013
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Ingår i: Journal of Aerosol Medicine. - : Mary Ann Liebert Inc. - 1941-2711 .- 1941-2703. ; 26:2, s. 84-93
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is currently a need to develop and test in vitro systems for predicting the toxicity of nanoparticles. One challenge is to determine the actual cellular dose of nanoparticles after exposure. Methods: In this study, human epithelial lung cells (A549) were exposed to airborne Cu particles at the air-liquid interface (ALI). The cellular dose was determined for two different particle sizes at different deposition conditions, including constant and pulsed Cu aerosol flow. Results: Airborne polydisperse particles with a geometric mean diameter (GMD) of 180nm [geometric standard deviation (GSD) 1.5, concentration 10(5) particles/mL] deposited at the ALI yielded a cellular dose of 0.4-2.6 mu g/cm(2) at pulsed flow and 1.6-7.6 mu g/cm(2) at constant flow. Smaller polydisperse particles in the nanoregime (GMD 80 nm, GSD 1.5, concentration 10(7) particles/mL) resulted in a lower cellular dose of 0.01-0.05 mu g/cm(2) at pulsed flow, whereas no deposition was observed at constant flow. Exposure experiments with and without cells showed that the Cu particles were partly dissolved upon deposition on cells and in contact with medium. Conclusions: Different cellular doses were obtained for the different Cu particle sizes (generated with different methods). Furthermore, the cellular doses were affected by the flow conditions in the cell exposure system and the solubility of Cu. The cellular doses of Cu presented here are the amount of Cu that remained on the cells after completion of an experiment. As Cu particles were partly dissolved, Cu (a nonnegligible contribution) was, in addition, present and analyzed in the nourishing medium present beneath the cells. This study presents cellular doses induced by Cu particles and demonstrates difficulties with deposition of nanoparticles at the ALI and of partially soluble particles.
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| 4. |
- Hedberg, Yolanda, et al.
(författare)
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Particles, sweat, and tears : A comparative study on bioaccessibility of ferrochromium alloy and stainless steel particles, the pure metals and their metal oxides, in simulated skin and eye contact
- 2010
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Ingår i: Integrated Environmental Assessment and Management. - : Wiley. - 1551-3777 .- 1551-3793. ; 6:3, s. 456-468
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Tidskriftsartikel (refereegranskat)abstract
- Ferrochromium alloys are manufactured in large quantities and placed on the global market for use as master alloys (secondary raw materials), primarily for stainless steel production. Any potential human exposure to ferrochromium alloy particles is related to occupational activities during production and use, with 2 main exposure routes, dermal contact and inhalation and subsequent digestion. Alloy and reference particles exposed in vitro in synthetic biological fluids relevant for these main exposure routes have been investigated in a large research effort combining bioaccessibility; chemical speciation; and material, surface, and particle characteristics. In this paper, data for the dermal exposure route, including skin and eye contact, will be presented and discussed. Bioaccessibility data have been generated for particles of a ferrochromium alloy, stainless steel grade AISI 316L, pure Fe, pure Cr, iron(II,III)oxide, and chromium(III)oxide, upon immersion in artificial sweat (pH 6.5) and artificial tear (pH 8.0) fluids for various time periods. Measured released amounts of Fe, Cr, and Ni are presented in terms of average Fe and Cr release rates and amounts released per amount of particles loaded. The results are discussed in relation to bulk and surface composition of the particles. Additional information, essential to assess the bioavailability of Cr released, was generated by determining its chemical speciation and by providing information on its complexation and oxidation states in both media investigated. The effect of differences in experimental temperature, 30 °C and 37 °C, on the extent of metal release in artificial sweat is demonstrated. Iron was the preferentially released element in all test media and for all time periods and ironcontaining particles investigated. The extent of metal release was highly pH dependent and was also dependent on the medium composition. Released amounts of Cr and Fe were very low (close to the limit of detection, <0.008% of particles released or dissolved as iron or chromium) for the alloy particles (ferrochromium alloy and stainless steel), the pure Cr particles, and the metal oxide particles. The released fraction of Cr (Cr/[Cr + Fe]) varied with the material investigated, the test medium, and the exposure time and cannot be predicted from either the bulk or the surface composition. Chromium was released as noncomplexed Cr(III) and in addition in very low concentrations (<3 mg/L). Nickel released was under the limit of detection (0.5 mg/L), except for ultrafine stainless steel particles (<10 mg/L). It is evident that media chemistry and material properties from a bulk and surface perspective, as well as other particle characteristics, and the chemical speciation of released metals have to be considered when assessing any potential hazard or risk induced by sparingly soluble metal or alloy particles.
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| 5. |
- Hedberg, Yolanda, et al.
(författare)
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Size matters : Mechanism of metal release from 316L stainless steel particles is governed by size-dependent properties of the surface oxide
- 2014
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Ingår i: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 122, s. 223-226
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Tidskriftsartikel (refereegranskat)abstract
- Size-dependent health aspects due to exposure to micro- or nano-sized particles can only be fully understood if their physicochemical properties are well characterized. The aim of this study was to explain the process of metal release from well-characterized inert gas atomized stainless steel 316L particles, sized < 4 gm (fine) and < 45 gm (coarse), in aggressive environments of relevance for inhalation and cellular uptake. This was accomplished by correlating new results from real-time metal release measurements with particle- and surface oxide characteristics. In simulated biological media with complexing properties, a complexation (ligand)-induced dissolution mechanism is dominating the metal release from fine 316L particles (having a homogeneous and amorphous Mn-rich surface oxide due to rapid cooling). At similar conditions, the coarse 316L particles show a metal release mechanism dominated by fast dissolution of surface oxide nanoparticles (rich in Mn, Fe, and some S), acting as initiation sites for metastable pitting corrosion.
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| 6. |
- Julander, Anneli, et al.
(författare)
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A Case Study of Brass Foundry Workers' Estimated Lead (Pb) Body Burden from Different Exposure Routes
- 2020
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Ingår i: Annals of Work Exposures and Health. - : Oxford University Press. - 2398-7308 .- 2398-7316. ; 64:9, s. 970-981
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The most pronounced occupational exposure routes for lead (Pb) are inhalation and gastrointestinal uptake mainly through hand-to-mouth behaviour. Skin absorption has been demonstrated for organic Pb compounds, but less is known about inorganic Pb species. Several legislative bodies in Europe are currently proposing lowering biological exposure limit values and air exposure limits due to new evidence on cardiovascular effects at very low blood Pb levels. In light of this, all exposure routes in occupational settings should be revisited to evaluate how to lower the overall exposure to Pb.METHODS: The aim of the study was to investigate the possible exposure routes in workers operating computer numerical control-machines in a brass foundry and specifically to understand if metal cutting fluids (MCFs) used by the workers could lead to skin absorption of Pb. The different bronze alloys at the facility may contain up to 20% Pb. After obtaining written informed consent from the workers (n = 7), blood, skin wipes, and personal air samples were collected. In addition, MCFs used on the day of exposure measurements were collected for in vitro skin absorption studies using stillborn piglet skin mounted in static Franz diffusion cells (n = 48). All samples were analysed for Pb content using inductively coupled plasma mass spectrometry.RESULTS: Pb air concentration (<0.1-3.4 µg m-3) was well below the Swedish occupational exposure limit value. Blood Pb was in the range of <0.72-33 µg dl-1, and Pb on skin surfaces, after performing normal work tasks during 2 h, was in the range of 0.2-48 µg cm-2. Using the MCFs in diffusion cells showed that skin absorption had occurred at very low doses, and that up to 10% of the Pb content was present in the skin after 24 h exposure. Using these results in the US EPA adult lead model, we could estimate a contribution to blood Pb from the three exposure routes; where hand-to-mouth behaviour yielded the highest contribution (16 µg Pb dl-1 blood), followed by skin absorption (3.3-6.3 µg Pb dl-1 blood) and inhalation (2.0 µg Pb dl-1 blood).CONCLUSIONS: This case study shows that MCF may lead to skin absorption of inorganic Pb and contribute to a systemic dose (quasi-steady state). Furthermore, even though good hand hygienic measures were in place, the workers' skin exposure to Pb is in all likelihood an important contributor in elevating blood Pb levels. Skin exposure should thus be monitored routinely in workers at facilities handling Pb, to help reducing unnecessary occupational exposure.
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| 7. |
- Julander, Anneli, et al.
(författare)
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New UK nickel-plated steel coins constitute an increased allergy and eczema risk
- 2013
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 68:6, s. 323-330
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Tidskriftsartikel (refereegranskat)abstract
- Background. Nickel-plated steel coins have recently been introduced in the United Kingdom. Objectives. To compare the performance and allergy risk of the new nickel-plated coins (five and ten pence) with those of the cupro-nickel coins being replaced. Materials and methods. Coin handling studies with assessment of skin exposure and metal release in artificial sweat were performed. Six volunteers participated. Results. The amount of nickel deposited onto skin during the handling of nickel-plated coins for 1 hr was 7.5 mu g/cm(2), four times higher than that from cupro-nickel coins. The nickel content in the oxidized surface of nickel-plated coins was higher, explaining the higher skin dose. Initial nickel release rates were 10-27 times higher than 1-week rates, emphasizing that brief and repeated contact results in significant nickel exposure. Conclusions. Nickel-plated coins deposit higher levels of nickel onto skin than cupro-nickel coins, and hence pose an increased allergy risk. One-week release in artificial sweat is not suitable for determining the risk of handling items with high nickel release that come into short, repeated contact with the skin. The nickel skin dose is recommended for risk assessment. UK citizens are now, because of this change in coinage, unnecessarily exposed to higher levels of nickel on the skin. This is of public health concern.
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| 8. |
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| 9. |
- Midander, Klara, et al.
(författare)
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Bioaccessibility of FERRO-chromium and ferrosilicon-chromium particles compared to pure metals and stainless steel-Aspects of human exposure
- 2010
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Ingår i: Proceedings of the 12th International Ferroalloys Congress: Sustainable Future. - 9789529273409 ; , s. 43-51
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Konferensbidrag (refereegranskat)abstract
- Product safety legislation requires that industry indentifies and demonstrates any human risks associated with the manufacture and use of products which are placed on the market throughout their entire life cycle. This process involves detailed assessment of potential hazards of the products/material related to health effect endpoints, and requires accurate generation and interpretation of data which can be used to determine essential characteristics of the material. Temporary or permanent adverse health effects depend either on the shape or physical characteristics of the particles, and/or on chemical interactions with the particle surface upon human exposure. Since alloys represent the most significant and widespread use of many engineering metals, it is important to develop a detailed understanding of the characteristics and behaviour of this group of materials with a minimum dependence on in-vivo testing. The aim of this presentation is to summarize generated bioaccessibility data for ferro-chromium and ferro-silicon-chromium alloys in particulate form when exposed to different synthetic biological media. The selection of test media aims to mimic relevant human exposures, as far as practical, with the focus on inhalation and subsequent ingestion of inhaled particles. The generation of bioaccessibility data combined with detailed particle and material characterization, also from a surface perspective, is essential for accurate risk assessment and understanding of potential adverse effects that may be caused by ferro-chromium and ferro-silicon-chromium alloys. For comparison, a similar approach has been conducted on particles of pure iron, pure chromium and stainless steel grade AISI 316L. Generated data is used within the framework of risk assessment on ferro-chromium and ferro-siliconchromium alloys conducted by the Finnish Institute of Occupational Health, Helsinki, Finland.
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| 10. |
- Midander, Klara, et al.
(författare)
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Bioaccessibility of nano- and micron-sized metallic particles in simulated lung systems
- 2008
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Konferensbidrag (refereegranskat)abstract
- Ambient airborne particles of varying size and composition, originating from anthropogenic and natural sources are today a recognized health risk in the society. The rapid development of engineered nanomaterials, including particles, is believed to become an issue of large concern. At present, few efforts have been made to investigate potential adverse health effects of nano- and micron sized metallic particles. Reliable data on surface properties and reactivity of metallic particles and its correlation to toxicity is scarce. Bioaccessibility data, in terms of metal release, is believed to reflect the toxic effects of metallic particles. The metal release process is influenced by particle size, i.e. surface area, shape and material type, e.g. passive/non-passive, pure/alloy/oxide as well as the exposure environment, e.g. within the lung. The assessment of potentially adverse health effects due to particles requires the correlation between toxic effects, bioaccessibility properties and surface characteristics. Within this context, the material aspects of metal release from Cu-particles were studied in-vitro by exposure in different synthetic biological media that simulate, to some extent, a realistic inhalation scenario. Particle toxicity in terms of DNA damage and cytotoxic effects was studied in collaboration with human toxicologists at Karolinska Institutet, and aerosol scientists at Stockholm University, using epithelial human lung cells.
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