The 2017-2019 hourly particle number size distributions (PNSD) from 26 sites in Europe and 1 in the US were evaluated focusing on 16 urban background (UB) and 6 traffic (TR) sites in the framework of Research Infrastructures services reinforcing air quality monitoring capacities in European URBAN & industrial areaS (RI-URBANS) project. The main objective was to describe the phenomenology of urban ultrafine particles (UFP) in Europe with a significant air quality focus.The varying lower size detection limits made it difficult to compare PN concentrations (PNC), particularly PN10-25, from different cities. PNCs follow a TR>UB>Suburban (SUB) order. PNC and Black Carbon (BC) progressively increase from Northern Europe to Southern Europe and from Western to Eastern Europe. At the UB sites, typical traffic rush hour PNC peaks are evident, many also showing midday-morning PNC peaks anti-correlated with BC. These peaks result from increased PN10-25, suggesting significant PNC contributions from nucleation, fumigation and shipping.Site types to be identified by daily and seasonal PNC and BC patterns are: (i) PNC mainly driven by traffic emissions, with marked correlations with BC on different time scales; (ii) marked midday/morning PNC peaks and a seasonal anti-correlation with PNC/BC; (iii) both traffic peaks and midday peaks without marked seasonal patterns. Groups (ii) and (iii) included cities with high insolation.PNC, especially PN25-800, was positively correlated with BC, NO2, CO and PM for several sites. The variable correlation of PNSD with different urban pollutants demonstrates that these do not reflect the variability of UFP in urban environments. Specific monitoring of PNSD is needed if nanoparticles and their associated health impacts are to be assessed. Implementation of the CEN-ACTRIS recommendations for PNSD measurements would provide comparable measurements, and measurements of <10 nm PNC are needed for full evaluation of the health effects of this size fraction. © Authors
Zinc oxide nanoparticles (ZnO NP) are often used in the food sector, among others, because of their advantageous properties. As part of the human food chain, they are inevitably taken up orally. The debate on the toxicity of orally ingested ZnO NP continues due to incomplete data. Therefore, the aim of our study was to examine the effects of two differently sized ZnO NP (<50 nm and <100 nm primary particle size; 123â€Ì614 mikromol/L) on two model systems of the intestinal barrier. Differentiated Caco-2 enterocytes were grown on Transwell inserts in monoculture and also in coculture with the mucus-producing goblet cell line HT29-MTX. Although no comprehensive mucus layer was detectable in the coculture, cellular zinc uptake was clearly lower after a 24-h treatment with ZnO NP than in monocultured cells. ZnO NP showed no influence on the permeability, metabolic activity, cytoskeleton and cell nuclei. The transepithelial electrical resistance was significantly increased in the coculture model after treatment with _307 _mol/L ZnO NP. Only small zinc amounts (0.07â€Ì0.65 mikrog/mL) reached the basolateral area. Our results reveal that the cells of an intact intestinal barrier interact with ZnO NP but do not suffer serious damage. Quelle: Artikel
Background: Zinc oxide nanoparticles (ZnO NP) offer beneficial properties for many applications, especially in the food sector. Consequently, as part of the human food chain, they are taken up orally. The toxicological evaluation of orally ingested ZnO NP is still controversial. In addition, their physicochemical properties can change during digestion, which leads to an altered biological behaviour. Therefore, the aim of our study was to investigate the fate of two different sized ZnO NP (< 50 nm and < 100 nm) during in vitro digestion and their effects on model systems of the intestinal barrier. Differentiated Caco-2 cells were used in mono- and coculture with mucus-producing HT29-MTX cells. The cellular uptake, the impact on the monolayer barrier integrity and cytotoxic effects were investigated after 24 h exposure to 123-614 mikroM ZnO NP. Results: In vitro digested ZnO NP went through a morphological and chemical transformation with about 70% free zinc ions after the intestinal phase. The cellular zinc content increased dose-dependently up to threefold in the monoculture and fourfold in the coculture after treatment with digested ZnO NP. This led to reactive oxygen species but showed no impact on cellular organelles, the metabolic activity, and the mitochondrial membrane potential. Only very small amounts of zinc (< 0.7%) reached the basolateral area, which is due to the unmodified transepithelial electrical resistance, permeability, and cytoskeletal morphology. Conclusions: Our results reveal that digested and, therefore, modified ZnO NP interact with cells of an intact intestinal barrier. But this is not associated with serious cell damage. Quelle: Artikel
Nanoparticles (NP) enter soils through various pathways. In soils, they undergo different interactions with the liquid and the solid phase. These interactions may govern the chemical and colloidal stability of the NP and hence affect their prospective fate. Understanding NP fate in saturated systems is of relevance in order to assess any potential risks for the contamination of groundwater, which often serves as a drinking water resource. In the literature, a fair body of knowledge has been established on the individual impacts of dissolved organic matter (DOM), multivalent ions, and intrinsic particle size on NP colloidal stability. However, little is known about the interactive effects of these parameters as well as the impact of the type of soilborne DOM. In batch studies, using different types of soil solutions, we investigated some of these interactions as well as the effect of DOM characteristics on NP stability. Further, the potential risk for a breakthrough of both environmentally "aged" NP and synthetically coated NP in an artificial riverbank filtration system was studied. In addition, factors leading to the remobilization of initially immobilized particles were identified. The presented work provides an overview on how environmentally-induced changes in NPâ€Ì surface characteristic control their fate in soils and water resources. Quelle: www.meetingorganizer.copernicus.org
Im Forschungsvorhaben "Untersuchungen zur möglichen Freisetzung von Nanopartikeln bei der Ablagerung und bodenbezogenen Anwendung von mineralischen Abfällen" wurden mögliche Freisetzungspfade von Nanopartikeln bei der Aufbereitung und Verwertung fester Verbrennungsrückstände aus der Haumüll- und Klärschlammverbrennung untersucht. Zu diesem Zweck wurden Hausmüll- und Klärschlammchargen mit nanoskaligem Titandioxid dotiert und anschließend in Verbrennungsanlagen thermisch behandelt. Die erzeugten nanomaterialhaltigen Schlacken und Aschen wurden unter Zuhilfenahme der Röntgenspektroskopie (REM EDX) hinsichtlich ihres Agglomerations- bzw. Aggregationsverhaltens untersucht und bewertet. Darüber hinaus wurden die Asche- und Schlackeproben im Hinblick auf Staubfreisetzung bei der mechanischen Aufbereitung bewertet und mittels Lysimeter- bzw. Deponiekörperreaktoren das Elutionsvermögen der Nanopartikel untersucht. Die Forschungsergebnisse legen eine besondere Sorgfalt bei der mechanischen Aufbereitung der Verbrennungsrückstände nahe, z.B. durch Maßnahmen wie Kapselung und Befeuchtung zur Minderung der Staubemissionen, sowie bei der bodenbezogenen Verwertung der Klärschlammverbrennungsaschen. Veröffentlicht in Texte | 136/2020.
Due to their beneficial properties, the use of zinc oxide nanoparticles (ZnO NP) is constantly increasing, especially in consumer-related areas, such as food packaging and food additives, which is leading to an increased oral uptake of ZnO NP. Consequently, the aim of our study was to investigate the cellular uptake of two differently sized ZnO NP (<50 nm and <100 nm; 12-1229 (micro)mol/L) using two human intestinal cell lines (Caco-2 and LT97) and to examine the possible resulting toxic effects. ZnO NP (<50 nm and <100 nm) were internalized by both cell lines and led to intracellular changes. Both ZnO NP caused time- and dose-dependent cytotoxic effects, especially at concentrations of 614 (micro)mol/L and 1229 (micro)mol/L, which was associated with an increased rate of apoptotic and dead cells. ZnO NP < 100 nm altered the cell cycle of LT97 cells but not that of Caco-2 cells. ZnO NP < 50 nm led to the formation of micronuclei in LT97 cells. The Ames test revealed no mutagenicity for both ZnO NP. Our results indicate the potential toxicity of ZnO NP after oral exposure, which should be considered before application. © 2021 by the authors
The fate of engineered nanoparticles in the aquatic-terrestrial transition zone is decisive for their effect in the environment. However, our knowledge on processes within this interface is rather low. Therefore, we used a floodplain stream mesocosm to enhance our understanding of the long-term distribution and biological effects of citrate-coated silver nanoparticles (Ag-NPs) in this ecosystem. Parallel to pulsed dosing of Ag-NPs, we observed fluctuating but successively increasing concentrations of aqueous Ag, 88-97% of which was categorized as particles. The remaining dissolved fraction was mainly complexed with natural organic matter (NOM). The major Ag fraction (50%) was associated with the uppermost sediment layer. The feeding activity of benthic amphipods was largely unaffected, which could be explained by the low Ag concentration and complexation of released Ag+ with NOM. According to our hypothesis, only a small nanoparticle fraction (6%) moved to the terrestrial area due to aquatic aging and enrichment of Ag-NPs in sediments and biota. Nanoparticle infiltration in deeper sediment and soil layers was also limited. We expect that a small fraction of nanoparticles remaining in the water for several weeks can be transported over large distances in rivers. The Ag-NPs accumulated in the top layer of sediment and soil may serve as a source of toxic Ag+ ions or may be remobilized due to changing physico-chemical conditions. Furthermore, the high enrichment of Ag-NPs on algae (up to 250 000-fold) and leaves (up to 11 000-fold) bears risk for organisms feeding on those resources and for the transfer of Ag within the food web. © Royal Society of Chemistry 2021
The enhancing effect on mechanical properties of boehmite (y-AlOOH)nanoparticles (BNP) in epoxy-based nanocomposites on the macroscopic scaleencouraged recent research to investigate the micro- and nanoscopic proper-ties. Several studies presented different aspects relatable to an alteration of theepoxy polymer network formation by the BNP with need for further experi-ments to identify the mode of action. With FTIR-spectroscopic methods thisstudy identifies interactions of the BNP with the epoxy polymer matrix duringthe curing process as well as in the cured nanocomposite. The data reveals thatnot the BNP themselves, but the water released from them strongly influencesthe curing process by hydrolysis of the anhydride hardener or protonation ofthe amine accelerator. The changes of the curing processes are discussed indetail. The changes of the curing processes enable new explanation for thechanged material properties by BNP discussed in recent research like alowered glass transition temperature region (Tg) and an interphase formation. © Authors
Standardized experimental approaches for the quantification of the bioaccumulation potential of nanomaterials in general and in (benthic) invertebrates in particular are currently lacking. We examined the suitability of the benthic freshwater amphipod Hyalella azteca for the examination of the bioaccumulation potential of nanomaterials. A flow-through test system that allows the generation of bioconcentration and biomagnification factors was applied. The feasibility of the system was confirmed in a 2-lab comparison study. By carrying out bioconcentration and biomagnification studies with gold, titanium dioxide and silver nanoparticles as well as dissolved silver (AgNO3) we were able to assess the bioaccumulation potential of different types of nanomaterials and their exposure pathways. For this, the animals were examined for their total metal body burden using inductively coupled mass spectroscopy (ICP-MS) and for the presence of nanoparticulate burdens using single-particle ICP-MS. The role of released ions was highlighted as being very important for the bioavailability and bioaccumulation of metals from nanoparticles for both examined uptake paths examined (bioconcentration and biomagnification). In 2018 a tiered testing strategy for engineered nanomaterials was proposed by Handy et al. that may allow a waiver of bioaccumulation fish studies using inter alia invertebrates. Data gained in studies carried out with invertebrates like the developed Hyalella azteca test may be included in this proposed tiered testing strategy. © 2020 The Author(s)
Erste wissenschaftliche Studien zum Verbleib von technischem Nanomaterial (ENM) in Abfallverbrennungsanlagen [BÖR16, LAN16, WAL12, BAR16] deuten darauf hin, dass der Großteil der verwendeten ENM in den festen Verbrennungsrückständen verbleibt, wobei es möglicherweise nicht dauerhaft in diesen gebunden wird [WAL12]. Dementsprechend verlagert sich der Fokus der Untersuchungen hin zu nachgelagerten Schritten in der Verwertung bzw. Entsorgung der nanomaterialhaltigen mineralischen Rückstände aus der Verbrennung. Dies wurde zum Anlass genommen, um im Rahmen des zwei-jährigen UFOPLAN-Vorhabens "Untersuchungen zur möglichen Freisetzung von Nanopartikeln bei der Ablagerung und bodenbezogenen Anwendung von mineralischen Abfällen" mögliche Emissionspfade für aus der Hausmüll- bzw. Klärschlammverbrennung stammende Nanopartikel mithilfe von Labor-versuchen zu untersuchen. Als ENM wurde nanoskaliges Titandioxid (nTiO2) in Form des Produkts Hombikat UV 100 WP der Fa. Venator eingesetzt. Nach der Herstellung ENM-haltiger HMV-Schlacken und Klärschlammaschen in großtechnischen Abfallbehandlungsanlagen, wurden diese in Laborversu-chen hinsichtlich ihres Staubungs- und Elutionsverhaltens untersucht. Bei den Staubungsversuchen wurde bei Proben mit geringem Wasseranteil Titan sowohl bei den untersuchten HMV-Schlacken als auch bei den Klärschlammaschen in der alveolengängigen, der thorakalen und der einatembaren Frak-tion des Staubs in höherer Konzentration als bei der Referenz detektiert. Bei den nassen Schlacken - welche typischerweise den Verhältnissen in der Praxis entsprechen - konnte Titan nur im thorakalen Staub gegenüber der Referenzprobe nachgewiesen werden. Neben den Staubungsversuchen wurden auch Elutionsversuche durchgeführt. In den Untersuchungen konnte gezeigt werden, dass standardisierte Labor-Elutionsverfahren in der Lage sind, im Vergleich mit Kontrollmaterialien erhöhte Mobilität von nTiO2 sicher anzuzeigen. Die beobachtete erhöhte Mobilität im Laborversuch konnten in Simu-lationsversuchen im Technikumsmaßstab bestätigt werden. Dort, wo die Elutionsversuche keine er-höhte Mobilität anzeigte, trat sie auch im Simulationsversuch nicht auf. Quelle: Forschungsbericht
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