| 1. |
- Abrahamsson, Camilla, et al.
(författare)
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Characterization of airborne dust emissions from three types of crushed multi-walled carbon nanotube-enhanced concretes
- 2024
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Ingår i: NanoImpact. - : Elsevier B.V.. - 2452-0748. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- Dispersing Multi-Walled Carbon Nanotubes (MWCNTs) into concrete at low (<1 wt% in cement) concentrations may improve concrete performance and properties and provide enhanced functionalities. When MWCNT-enhanced concrete is fragmented during remodelling or demolition, the stiff, fibrous and carcinogenic MWCNTs will, however, also be part of the respirable particulate matter released in the process. Consequently, systematic aerosolizing of crushed MWCNT-enhanced concretes in a controlled environment and measuring the properties of this aerosol can give valuable insights into the characteristics of the emissions such as concentrations, size range and morphology. These properties impact to which extent the emissions can be inhaled as well as where they are expected to deposit in the lung, which is critical to assess whether these materials might constitute a future health risk for construction and demolition workers. In this work, the impact from MWCNTs on aerosol characteristics was assessed for samples of three concrete types with various amounts of MWCNT, using a novel methodology based on the continuous drop method. MWCNT-enhanced concretes were crushed, aerosolized and the emitted particles were characterized with online and offline techniques. For light-weight porous concrete, the addition of MWCNT significantly reduced the respirable mass fraction (RESP) and particle number concentrations (PNC) across all size ranges (7 nm – 20 μm), indicating that MWCNTs dampened the fragmentation process by possibly reinforcing the microstructure of brittle concrete. For normal concrete, the opposite could be seen, where MWCNTs resulted in drastic increases in RESP and PNC, suggesting that the MWCNTs may be acting as defects in the concrete matrix, thus enhancing the fragmentation process. For the high strength concrete, the fragmentation decreased at the lowest MWCNT concentration, but increased again for the highest MWCNT concentration. All tested concrete types emitted <100 nm particles, regardless of CNT content. SEM imaging displayed CNTs protruding from concrete fragments, but no free fibres were detected.
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| 2. |
- Arvidsson, Rickard, 1984, et al.
(författare)
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Influence of natural organic matter on the aquatic ecotoxicity of engineered nanoparticles: Recommendations for environmental risk assessment
- 2020
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigate whether the influence of natural organic matter (NOM) on the aquatic ecotoxicity of engineered nanoparticles (ENPs) can be described quantitatively for the purpose of risk assessments based on existing ecotoxicity studies. A review of the literature studying the aquatic ecotoxicity of ENPs in the presence of NOM identified 66 studies in total, covering the metal and metal oxide ENPs most commonly used in consumer products. It was found that 80% of the studies show a reduction in ENP ecotoxicity in the presence of NOM. Analyses of ecotoxicity data based on 50% effect/inhibition/lethal concentrations (collectively referred to as XC50) were conducted. Correlations of XC50 values with the concentrations of NOM were investigated through Spearman's rank correlation coefficient as well as linear, power law, polynomial, exponential and logarithmic correlations. Furthermore, multiple linear regression (MLR) analyses, including also the pH in the reviewed ecotoxicity test systems (mainly in the range pH 7.0–8.5), were conducted. While none of these statistical approaches provided strong empirical correlations between XC50 values, NOM concentration and pH, an empirical rule of thumb was discovered for the ratio between XC50 values with and without NOM over an environmentally realistic concentration range for NOM (0.1–10 mg/L): XC50 values obtained in experiments with NOM present tended to be a factor of 1–10 higher than those without NOM. Until more accurate correlations are provided, a pragmatic approach for environmental risk assessments of ENPs might therefore be to use observed XC50 values from experiments without NOM present as reasonably conservative proxies for XC50 values with NOM present. Further studies are needed to confirm or falsify this rule of thumb for different ENPs, environmental conditions and metrics.
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| 3. |
- Arvidsson, Rickard, 1984, et al.
(författare)
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Prospective environmental risk screening of seven advanced materials based on production volumes and aquatic ecotoxicity
- 2022
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 25
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Tidskriftsartikel (refereegranskat)abstract
- The number and volume of advanced materials being manufactured is increasing. In order to mitigate future impacts from such materials, assessment methods that can provide early indications of potential environmental risk are required. This paper presents a further development and testing of an environmental risk screening method based on two proxy measures: aquatic ecotoxicity and global annual production volumes. In addition to considering current production volumes, this further developed method considers potential future production volumes, thereby enabling prospective environmental risk screening. The proxy measures are applied to seven advanced materials: graphene, graphene oxide, nanocellulose, nanodiamond, quantum dots, nano-sized molybdenum disulfide, and MXenes. Only MXenes show high aquatic ecotoxicity, though the number of test results is still very limited. While current production volumes are relatively modest for most materials, several of the materials (graphene, graphene oxide, nanocellulose, nano-sized molybdenum disulfide, and MXenes) have the potential to become high-volume materials in the future. For MXenes, with both high aquatic ecotoxicity and high potential future production volumes, more detailed environmental risk assessments should be considered. For the other materials with high potential future production volumes, the recommendation is to continuously monitor their aquatic ecotoxicity data. Based on the application of the proxy measures combined with future scenarios for production volumes, we recommend this environmental risk screening method be used in the early development of advanced materials to prioritize which advanced materials should be subject to more detailed environmental assessments.
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| 4. |
- Bastos, Carlos A.P., et al.
(författare)
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Copper nanoparticles have negligible direct antibacterial impact
- 2020
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Soluble copper that can be acquired by bacteria is toxic and therefore antimicrobial. Whether nanostructured copper materials, in either disperse or agglomerated form, have antimicrobial impact, aside from that of their dissolution products, is not clear and was herein addressed. Methods: We took five nanostructured copper materials, two metallic, and three oxo-hydroxides with one of these being silicate-substituted. Four agglomerated in the bacterial growth media whilst the silicate-substituted material remained disperse and small (6.5 nm diameter). Antibacterial activity against E. coli was assessed with copper phase distribution measured over time. Using the dose of soluble copper, and benchmark dose non-linear regression modelling, we determined how well this phase predicted antimicrobial activity. Finally, we used Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis to investigate whether membrane adhe- sion effects by copper were plausible or if intracellular uptake most likely explained the bacterial impact of copper. Results: Comparison over time of antimicrobial activity against particulate or soluble phases of the aquated materials clearly demonstrated that soluble copper but not particulate forms were associated with inhibition of bacterial growth. Indeed, the benchmark dose modelling showed the soluble dose required to cause a 50% reduction in E. coli growth was strongly clustered – for all particle formulations – at 14.5 mg/L (10–19 mg/L 90% confidence interval). By comparison, total copper levels associated with the same reduction in viability varied widely (45–549 mg/L). Finally, in favour of this soluble product dominance in terms of antimicrobial activity, copper had low association with bacterial membrane (something both soluble and particulate materials could do) but showed high intra-bacterial levels (something only soluble copper could do). Conclusion: Taken together our data show that it is the uptake of soluble but not particulate copper, and the intracellular loading not just contact and membrane association, that drives copper toxicity to bacteria. Therapeutic strategies for novel antimicrobial copper compounds should consider these findings.
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| 5. |
- Book, Frida, 1989, et al.
(författare)
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Ecotoxicity screening of seven different types of commercial silica nanoparticles using cellular and organismic assays : Importance of surface and size
- 2019
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 13, s. 100-111
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Tidskriftsartikel (refereegranskat)abstract
- We show that seven different types of commercial, biocide-free, colloidal silica products with mean particle sizes between 17 and 88 nm with 3 different surface chemistries (Na-stabilized, aluminized and silane-modified) are not toxic to the bacterium Pseudomonas putida, and the algae Raphidocelis subcapitata in the concentration range 5–500 mg/L. They are also not acutely toxic to Daphnia magna at concentrations up to 10,000 mg/L. Six silica particles are toxic to the gill cell line RTgill-W1 from Rainbow trout (Oncorhynchus mykiss), showing a clear concentration-response relationship with EC50 values between 13 and 92 mg/L. Toxicity in the fish cells decreases with increasing hydrodynamic size and is dependent on particle surface area. The average EC50 across the tested particles is 2.1 (±0.3) m2/L. Surface modifications clearly impact toxicity, with silane-modified particles showing no cytotoxicity. The reduced number of free silanol groups on the surface of the silane modified particle, in combination with an increased steric hindrance that prevents contact with the cells is a possible mechanism for the observed lack of toxicity. This is also in line with previous studies on silica nanoparticles in human toxicology. Overall, these findings show a generally low ecotoxicity of silica nanoparticles and indicate that silica particles of different sizes but identical surface chemistry could potentially be grouped into an assessment group under regulation such as REACH.
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| 6. |
- Cornelis, Geert
(författare)
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Toxicokinetics of Ag from Ag2S NP exposure in Tenebrio molitor and Porcellio scaber: Comparing single-species tests to indoor mesocosm experiments
- 2023
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- Determining the potential for accumulation of Ag from Ag2S NPs as an environmentally relevant form of AgNPs in different terrestrial organisms is an essential component of a realistic risk assessment of AgNP emissions to soils. The objectives of this study were first to determine the uptake kinetics of Ag in mealworms (Tenebrio molitor) and woodlice (Porcellio scaber) exposed to Ag2S NPs in a mesocosm test, and second, to check if the obtained toxicokinetics could be predicted by single-species bioaccumulation tests. In the mesocosms, meal-worms and woodlice were exposed together with plants and earthworms in soil columns spiked with 10 mu g Ag g(-1) dry soil as Ag2S NPs or AgNO3. The total Ag concentrations in the biota were measured after 7, 14, and 28 days of exposure. A one-compartment model was used to calculate the Ag uptake and elimination rate constants. Ag from Ag2S NPs appeared to be taken up by the mealworms with significantly different uptake rate constants in the mesocosm compared to single-species tests (K-1 = 0.056 and 1.66 g dry soil g(-1) dry body weight day(-1), respectively), and a significant difference was found for the Ag bioaccumulation factor (BAFk = 0.79 and 0.15 g dry soil g(-1) dry body weight, respectively). Woodlice did not accumulate Ag from Ag2S NPs in both tests, but uptake from AgNO3 was significantly slower in mesocosm than in single-species tests (K-1 = 0.037 and 0.26 g dry soil g(-1) dry body weight day(-1), respectively). Our results are of high significance because they show that single-species tests may not be a good predictor for the Ag uptake in mealworms and woodlice in exposure systems having greater levels of biological complexity. Nevertheless, single-species tests could be used as a fast screening approach to assess the potential of a substance to accumulate in biota before more complex tests are conducted.
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| 7. |
- Danielsson, Karin, et al.
(författare)
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Effects of the adsorption of NOM model molecules on the aggregation of TiO2 nanoparticles in aqueous suspensions
- 2018
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 10, s. 177-187
-
Tidskriftsartikel (refereegranskat)abstract
- © 2018 Interaction of synthetic TiO2(anatase) nanoparticles in aqueous suspension at pH 5 was investigated as a function of time in the presence of various organic molecules in terms of adsorption and aggregation behaviour. ζ-potential and average particle diameter were determined with electrophoretic and dynamic light scattering, respectively, while batch adsorption experiments were used to quantify the amount of organic ligand adsorbed to the TiO2NP. An IR spectroscopic study was carried out at pH 2.8 and 5 to gain information about the interactions of the adsorbed molecules with the TiO2surface on the molecular level. Furthermore, DLVO calculations provided information about the interaction energies between particles and their tendency to aggregate under some experimental conditions. Colloidal stability of TiO2NPs in the presence of organic molecules was studied during a time period of up to 90 days. Results showed that ligands with different functional groups may interact differently with the surface depending on the type and position of available surface sites, the molecular structure of the ligand and suspension pH. Adsorption, hydrodynamic diameter and ζ-potential were affected by the ligand concentration in all tested systems. Increased concentration gave rise to increased adsorption, while ζ-potential decreased and charge inversion was observed for all tested molecules at pH 5. IR spectroscopic study showed the formation of inner sphere and/or outer sphere complexes depending on pH and type of organic ligand. According to DLVO calculations, the critical coagulation concentration (CCC) indicated a trend of increasing colloidal stability with increased concentration of SRFA at pH 5, which was in agreement with the experimental data.
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| 8. |
- Gallego-Urrea, Julian A., 1977, et al.
(författare)
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Coagulation and sedimentation of gold nanoparticles and illite in model natural waters: Influence of initial particle concentration
- 2016
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 3-4, s. 67-74
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Tidskriftsartikel (refereegranskat)abstract
- Gold nanoparticles (AuNP) possess unique characteristics that render them adequate for applications and also to be used as a model NP to evaluate the fate and behavior at low NP concentrations due to the ease of detection by modern analytical techniques. Moreover, AuNP may result in some negative effects in the environment and there is a necessity to predict their aquatic environmental concentrations by parameterizing the underlying transport and transformation processes. This study investigated the coagulation and sedimentation of 30 nm citrate-coated AuNP under enviro-mimicking conditions, i.e. model natural freshwaters (MNW) covering the range of European water chemistries relevant for colloids and NP (major ions, pH and dissolved organic matter) and artificial seawater (ASW). Firstly, the coagulation rates of AuNP at mg/L concentrations were evaluated using time-resolved dynamic light scattering which showed a decreased rate upon addition of Suwannee river natural organic matter (SRNOM) at low ionic strength (IS) but remained relatively high at high IS. Contrastingly, AuNP approaching environmental realistic concentrations (80 μg/L) in quiescent microcosms showed slow decline rates in all MNW and ASW regardless of the presence of SRNOM, as measured by nanoparticle tracking analysis and elemental Au spectrometry. When illite was added as model natural colloid the rates of decline of AuNP remained low as well. This is owing to limited collisions at low particle number concentrations. The results show that besides IS, pH, NOM concentration and type and the intrinsic surface charge of the particles, the particle number concentration and size distribution of both AuNP and natural colloids determine the extent of the large-scale fate of NP in aquatic environments.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Hartmann, Nanna B., et al.
(författare)
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NanoCRED : A transparent framework to assess the regulatory adequacy of ecotoxicity data for nanomaterials - Relevance and reliability revisited
- 2017
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 6, s. 81-89
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Tidskriftsartikel (refereegranskat)abstract
- Environmental hazard and risk assessment serve as the basis for regulatory decisions to protect the environment from unintentional adverse effects of chemical substances including nanomaterials. This process requires reliable and relevant environmental hazard data upon which classification and labelling can be based and Predicted No-Effect Concentration (PNEC) values can be estimated. In a regulatory context ecotoxicological data is often recommended to be generated according to accepted and validated test guidelines, preferably also following Good Laboratory Practice. However, engineered nanomaterials are known to behave very differently in ecotoxicity tests compared to the conventional soluble chemicals, for which most guidelines were developed. Therefore non-guideline tests, or tests following modified test guidelines, can provide valuable information and should not per se be considered less adequate for regulatory use. Here we propose a framework for reliability and relevance evaluation of ecotoxicity data for nanomaterials that take into account the challenges and characterisation requirements associated with testing of these substances. The nanoCRED evaluation criteria, and accompanying guidance, were developed to be used in combination with those developed through the ‘Criteria for Reporting and Evaluating Ecotoxicity Data (CRED)’ project. This approach can accommodate all types of nanomaterials, all types of aquatic ecotoxicity studies, and qualitative as well as quantitative data evaluation requirements. Furthermore, it is practically feasible to implement and directly applicable in European as well as international regulatory frameworks.
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| 13. |
- Janhäll, Sara, 1965-, et al.
(författare)
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Release of carbon nanotubes during combustion of polymer nanocomposites in a pilot-scale facility for waste incineration
- 2021
-
Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 24
-
Tidskriftsartikel (refereegranskat)abstract
- Nanocomposites, formed by incorporating nanoparticles into a matrix of standard materials, are increasing on the market. Little focus has been directed towards safe disposal and recycling of these new materials even though the disposal has been identified as a phase of the products' life cycle with a high risk of uncontrolled emissions of nanomaterials. In this study, we investigate if the carbon nanotubes (CNTs), when used as a filler in two types of polymers, are fully destructed in a pilot-scale combustion unit designed to mimic the combustion under waste incineration. The two polymer nanocomposites studied, polycarbonate (PC) with CNT and high-density polyethylene (HDPE) with CNT, were incinerated at two temperatures where the lower temperature just about fulfilled the European waste incineration directive while the upper was chosen to be on the safe side of fulfilling the directive. Particles in the flue gas were sampled and analysed with online and offline instrumentation along with samples of the bottom ash. CNTs could be identified in the flue gas in all experiments, although present to a greater extent when the CNTs were introduced in PC as compared to in HDPE. In the case of using PC as polymer matrix, CNTs were identified in 3–10% of the analysed SEM images while for HDPE in only ~0.5% of the images. In the case of PC, the presence of CNTs decreased with increasing bed temperature (from 10% to 3% of the images). The CNTs identified were always in bundles, often coated with remnants of the polymer, forming particles of ~1–4 μm in diameter. No CNTs were identified in the bottom ash, likely explained by the difference in time when the bottom ash and fly ash are exposed to high temperatures (~hours compared to seconds) in the pilot facility. The results suggest that the residence time of the fly ash in the combustion zone is not long enough to allow full oxidation of the CNTs. Thus, the current regulation on waste incineration (requiring a residence time of the flue gas >850 °C during at least 2 s) may not be enough to obtain complete destruction of CNTs in polymer composites. Since several types of CNTs are known to be toxic, we stress the need for further investigation of the fate and toxicity of CNTs in waste treatment processes.
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| 14. |
- Kaegi, R., et al.
(författare)
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Release of TiO2 – (Nano) particles from construction and demolition landfills
- 2017
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 8, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- A large fraction of engineered nanomaterials (ENM) will be deposited in landfills and it is assumed that ENM are securely locked in landfill sites and cannot leach into the environment (e.g. surface waters). However, experimental evidence supporting this assumption is lacking, as current production volumes of ENM are still too small and/or analytical techniques not sensitive enough to allow for the detection and quantification of ENM in landfill leachates. TiO2 particles are currently used in large quantities, for example in construction materials such as paints and renders as white pigments and their sizes extend into the nano-size range. We, therefore, selected TiO2 particles as a surrogate to assess the potential release of ENM from construction and demolition (C&D) landfill sites. We collected leachate samples from a landfill over one year and used complementary analytical techniques, including inductively coupled plasma (ICP) – optical emission spectroscopy (OES), automated scanning electron microscopy (auto SEM), transmission electron microscopy (TEM) and single particle ICP - mass spectrometry (spICPMS) to quantify TiO2 particles in landfill leachates. Total elemental Ti contents were mostly around a few tens of μg L− 1 and were strongly correlated with total suspended solids. Based on the volumetric discharge of the landfill leachate water from the landfill, we estimate a total amount of ~ 0.5 kg of TiO2 particles that are released annually from the landfill. Ti concentrations derived from ICP-OES measurements were in good agreement with quantifications based on TiO2 particles detected by auto SEM analyses. spICPMS measurements indicated a number concentration of Ti-containing particles in the order of 105 mL− 1 and TEM analyses dominantly revealed nanoscale TiO2 particles with a spherical shape typically observed for TiO2 particles used as white pigments. In addition, angular TiO2 particles with a well-defined crystal habitus were detected, suggesting that also natural TiO2 particles of comparable sizes are present in the landfill leachates. The results from this study indicate that (nanoscale) TiO2 particles are released from C&D landfill sites (~ 5 g/year). Although the amount of TiO2 particles released from C&D landfill sites may still be rather low, these particles may serve as proxy for assessing the future release of ENM from C&D landfill sites, which may become relevant as an increasing use of ENM is predicted for construction materials in general. © 2017 Elsevier B.V.
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| 15. |
- Khort, Alexander, et al.
(författare)
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Eco-corona-mediated transformation of nano-sized Y2O3 in simulated freshwater : A short-term study
- 2024
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Ingår i: NanoImpact. - 2452-0748. ; 33
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Tidskriftsartikel (refereegranskat)abstract
- The use of metal and metal oxide nanomaterials (NMs) is experiencing a significant surge in popularity due to their distinctive structures and properties, making them highly attractive for a wide range of applications. This increases the risks of their potential negative impact on organisms if dispersed into the environment. Information about their behavior and transformation upon environmental interactions in aquatic settings is limited. In this study, the influence of naturally excreted biomolecules from the zooplankton Daphnia magna on nanosized Y2O3 of different concentrations was systematically examined in synthetic freshwater in terms of adsorption and eco-corona formation, colloidal stability, transformation, dissolution, and ecotoxicity towards D. magna. The formation of an eco-corona on the surface of the Y2O3 NMs leads to improved colloidal stability and a reduced extent of dissolution. Exposure to the Y2O3 NMs lowered the survival probability of D. magna considerably. The ecotoxic potency was slightly reduced by the formation of the eco-corona, though shown to be particle concentration-specific. Overall, the results highlight the importance of systematic mechanistic and fundamental studies of factors that can affect the environmental fate and ecotoxic potency of NMs.
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| 16. |
- Khort, Aliaksandr, Dr, 1987-, et al.
(författare)
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Influence of natural organic matter on the transformation of metal and metal oxide nanoparticles and their ecotoxic potency in vitro
- 2022
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Ingår i: Nanoimpact. - : Elsevier BV. - 2452-0748. ; 25
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Tidskriftsartikel (refereegranskat)abstract
- Increased use and production of engineered nanoparticles (NPs) lead to an elevated risk of their diffuse dispersion into the aquatic environment and increased concern on unknown effects induced by their release into the aquatic ecosystem. An improved understanding of the environmental transformation processes of NPs of various surface characteristics is hence imperative for risk assessment and management. This study presents results on effects of natural organic matter (NOM) on the environmental transformation and dissolution of metal and metal oxide NPs of different surface and solubility properties in synthetic freshwater (FW) with and without NOM. Adsorption of NOM was evident on most of the studied NPs, except Sb and Sb2O3, which resulted in the formation of negatively charged colloids of higher stability and smaller size distribution compared with the same NPs in FW only. The dissolution rate of the NPs in the presence of NOM correlated with the strength of interactions between the carboxylate group of NOM and the particle surface, and resulted in either no (Mn, Sb, ZnO NPs), increased (Co, Sn NPs) and decreased (Ni, NiO, Sb2O3, Y2O3 NPs) levels of dissolution. One type of metal NP from each group (Mn, Ni, Sn) were investigated to assess whether observed differences in adsorption of NOM and dissolution would influence their ecotoxic potency. The results showed Mn, Ni, and Sn NPs to generate intracellular reactive oxygen species (ROS) in a time and dose-dependent manner. The extent of ROS generation in FW was similar for both Mn and Ni NPs but higher for Sn NPs. These findings are possibly related to interactions and infiltration of the NPs with the cells, which lead to redox imbalances which could induce oxidative stress and cell damage. At the same time, the presence of NOM generally reduced the intracellular ROS generation by 20-40% for the investigated NPs and also reduced cytotoxicity of Sn NPs, which can be attributed to the stronger interaction of carboxylate groups of NOM with the surface of the NPs.
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| 17. |
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| 18. |
- Lammel, Tobias, et al.
(författare)
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Assessment of titanium dioxide nanoparticle toxicity in the rainbow trout (Onchorynchus mykiss) liver and gill cell lines RTL-W1 and RTgill-W1 under particular consideration of nanoparticle stability and interference with fluorometric assays
- 2018
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Ingår i: Nanoimpact. - : Elsevier BV. - 2452-0748. ; 11, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- The increasing release of titanium dioxide (TiO2) nanoparticles (NPs) into the environment calls for a thorough assessment of their hazard to aquatic organisms. In vitro-assays based on continuous fish cell lines bear a high potential for determining the relative cytotoxic potency and mode of toxic action of environmental contaminants. Their application for testing of manufactured nanomaterials is however concomitant with technical challenges. The objective of this study was to determine the acute cytotoxicity of TiO2 NP in the rainbow trout (Onchorynchus mykiss) liver and gill cell lines RTL-W1 and RTgill-W1 under special consideration of so far widely ignored issues arising from poor NP stability and NP-dependent interference with fluorometric assays. We validated a protocol for the preparation of serum albumin-stabilized TiO2 NP dispersions in two growth media, which are frequently used in the culture of fish cells, Leibovitz-15 (L-15) and L-15/ex. The TiO2 NPs dispersions displayed high colloidal stability with their size distribution remaining unchanged over a concentration range that spans two orders of magnitude (1-100 mu g/ml) and an incubation period of 72 h. The TiO2 NPs dispersions caused little cytotoxicity upon 24 h and 72 h exposure, but NP agglomerates/aggregates were found inside intracellular vesicles in both gill and liver cells. Furthermore we demonstrated that TiO2 NPs, which remained adsorbed to the plasma membrane and/or were internalized by the cell interfere with fluorometric cell viability assays by attenuating part of the incident and emitted light resulting in effect overestimation. We propose modifications in the original assay protocol that may allow quantifying and mathematically correcting for the level of interference at different exposure concentrations.
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| 19. |
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| 20. |
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| 21. |
- Marcoulaki, Effie, et al.
(författare)
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Blueprint for a self-sustained European Centre for service provision in safe and sustainable innovation for nanotechnology
- 2021
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Ingår i: NanoImpact. - : Elsevier B.V.. - 2452-0748. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- The coming years are expected to bring rapid changes in the nanotechnology regulatory landscape, with the establishment of a new framework for nano-risk governance, in silico approaches for characterisation and risk assessment of nanomaterials, and novel procedures for the early identification and management of nanomaterial risks. In this context, Safe(r)-by-Design (SbD) emerges as a powerful preventive approach to support the development of safe and sustainable (SSbD) nanotechnology-based products and processes throughout the life cycle. This paper summarises the work undertaken to develop a blueprint for the deployment and operation of a permanent European Centre of collaborating laboratories and research organisations supporting safe innovation in nanotechnologies. The proposed entity, referred to as “the Centre”, will establish a ‘one-stop shop’ for nanosafety-related services and a central contact point for addressing stakeholder questions about nanosafety. Its operation will rely on significant business, legal and market knowledge, as well as other tools developed and acquired through the EU-funded EC4SafeNano project and subsequent ongoing activities. The proposed blueprint adopts a demand-driven service update scheme to allow the necessary vigilance and flexibility to identify opportunities and adjust its activities and services in the rapidly evolving regulatory and nano risk governance landscape. The proposed Centre will play a major role as a conduit to transfer scientific knowledge between the research and commercial laboratories or consultants able to provide high quality nanosafety services, and the end-users of such services (e.g., industry, SMEs, consultancy firms, and regulatory authorities). The Centre will harmonise service provision, and bring novel risk assessment and management approaches, e.g. in silico methodologies, closer to practice, notably through SbD/SSbD, and decisively support safe and sustainable innovation of industrial production in the nanotechnology industry according to the European Chemicals Strategy for Sustainability.
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| 22. |
- Romeo, Daina, et al.
(författare)
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Structure-activity relationship of graphene-related materials: A meta-analysis based on mammalian in vitro toxicity data
- 2022
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 28
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Tidskriftsartikel (refereegranskat)abstract
- To support a safe application of graphene-related materials (GRMs) it is necessary to understand the potential negative impacts they could have on human health, in particular on the lung -one of the most sensitive exposure routes. Machine learning (ML) approaches can help analyse the results of multiple toxicity studies to understand the structure-activity relationship and the effect of experimental conditions, thus supporting predictive nano -toxicology. In this work we collected in vitro cytotoxicity data obtained from studies using lung cells; we then fitted multiple regression models to predict this endpoint based on the material properties and experimental conditions. Moreover, the data set was used to calculate the Benchmark Dose Lower Confidence Interval (BMDL), a dose descriptor widely used in risk assessment. Regression and classification models were applied for the prediction of the BMDL value and BMDL range. The analyses show that both cytotoxicity and the BMDL range can be predicted well (Q2 = 0.77 and accuracy = 0.71, respectively). Both physico-chemical characteristics such as the lateral size, number of layers, and functionalization, and experimental conditions such as the assay and media used were important predicting features, confirming the need for thorough characterization and reporting of these parameters.
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| 23. |
- Ruggiero, Emmanuel, et al.
(författare)
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Food contact of paper and plastic products containing SiO2, Cu-Phthalocyanine, Fe2O3, CaCO3: Ranking factors that control the similarity of form and rate of release
- 2022
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 25
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Tidskriftsartikel (refereegranskat)abstract
- The paper industry is an important sector annually consuming kilotons of nanoforms and non-nanoforms of fillers and pigments. Fillers accelerate the rate of drying (less energy needed) and product cost (increasing the load of low-cost fillers). The plastic industry is another use sector, where coloristic pigments can be in nanoform, and many food containers are made of plastic. Use of paper to wrap both wet and dry food is consumer practice, but not always intended by producers. Here we compare the release behavior of different nano-enabled products (NEPs) by changing a) nanoform (NF) characteristics, b) NF load, c) the nano-enabled product (NEP) matrix, and d) food simulants. The ranking of these factors enables an assessment of food contact by concepts of analogy, specifically via the similarities of the rate and form of release in food during contact. Three types of matrices were used: Paper, plastic ((Polylactic Acid (PLA), Polyamide (PA6), and Polyurethane (PU)), and a paint formulation. Two nanoforms each of SiO2, Fe2O3, Cu-Phthalocyanine were incorporated, additionally to the conventional form of CaCO3 that is always contained in paper to reduce cellulose consumption. Tests were guided by the European Regulation EC 1935/2004 and EU 10/2011. No evidence of particle release was observed: the qualitative similarity (the form of release) was high regarding the food contact of all NEPs with embedded NFs. Quantitative similarity of releases depended primarily on the NEP matrix, as this controls the penetration of the simulant fluid into the NEP. The solubility of the NF and impurities in the simulant fluid was the second decisive factor, as dissolution of the NF inside the NEP is the main mechanism of release. This led to complete removal of CaCO3 in acidic medium, whereas Fe and Si signals remained in the paper, consistent with the low release rates in an ionic form. In our set of 16 NEPs, only one NEP showed a dependence on the REACH NF descriptors (substance, size, shape, surface treatment, crystallinity, impurities), specifically attributed to differences in soluble impurities, whereas for all others the substance of the nanoform was sufficient to predict a similarity of food contact release, without influences of size, shape, surface treatment and crystallinity.
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| 24. |
- Storsjö, Tobias, et al.
(författare)
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Elemental carbon - An efficient method to measure occupational exposure from materials in the graphene family
- 2024
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Ingår i: NanoImpact. - 2452-0748. ; 33
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Tidskriftsartikel (refereegranskat)abstract
- Graphene is a 2D-material with many useful properties such as flexibility, elasticity, and conductivity among others. Graphene could therefore become a material used in many occupational fields in the future, which can give rise to occupational exposure. Today, exposure is unknown, due to the lack of efficient measuring techniques for occupational exposure to graphene. Readily available screening techniques for air sampling and -analysis are either nonspecific or nonquantitative. Quantifying materials from the broad graphene family by an easy-to-use method is important for the large-scale industrial application of graphene, especially when for the safety of working environment. Graphene consists primarily of elemental carbon, and the present study evaluates the organic carbon/elemental carbon (OC/EC)-technique for exposure assessment. The purpose of this work is to evaluate the OC/EC analysis technique as an efficient and easy-to-use method for quantification of occupational exposure to graphene. Methods that can identify graphene would be preferable for screening, but they are time consuming and semi-quantitative and therefore not suited for quantitative work environment assessments. The OC/EC-technique is a thermal optical analysis (TOA), that quantitively determines the amount of and distinguishes between two different types of carbon, organic and elemental. The technique is standardised, well-established and among other things used for diesel exposure measurements (ref standard). OC/EC could therefore be a feasible measuring technique to quantitively determine occupational exposure to graphene. The present evaluation of the technique provides an analytical method that works quantitatively for graphene, graphene oxide and reduced graphene oxide. Interestingly, the TOA technique makes it possible to distinguish between the three graphene forms used in this study. The technique was tested in an industrial setting and the outcome suggests that the technique is an efficient monitoring technique to be used in combination with characterisation techniques like for example Raman spectroscopy, scanning electron microscopy and atomic force microscopy.
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