Found 9757 publications. Showing page 328 of 391:
Safety assessment of titanium dioxide (E171) as a food additive
The present opinion deals with an updated safety assessment of the food additive titanium dioxide (E 171) based on new relevant scientific evidence considered by the Panel to be reliable, including data obtained with TiO2 nanoparticles (NPs) and data from an extended one-generation reproductive toxicity (EOGRT) study. Less than 50% of constituent particles by number in E 171 have a minimum external dimension < 100 nm. In addition, the Panel noted that constituent particles < 30 nm amounted to less than 1% of particles by number. The Panel therefore considered that studies with TiO2 NPs < 30 nm were of limited relevance to the safety assessment of E 171. The Panel concluded that although gastrointestinal absorption of TiO2 particles is low, they may accumulate in the body. Studies on general and organ toxicity did not indicate adverse effects with either E 171 up to a dose of 1,000 mg/kg body weight (bw) per day or with TiO2 NPs (> 30 nm) up to the highest dose tested of 100 mg/kg bw per day. No effects on reproductive and developmental toxicity were observed up to a dose of 1,000 mg E 171/kg bw per day, the highest dose tested in the EOGRT study. However, observations of potential immunotoxicity and inflammation with E 171 and potential neurotoxicity with TiO2 NPs, together with the potential induction of aberrant crypt foci with E 171, may indicate adverse effects. With respect to genotoxicity, the Panel concluded that TiO2 particles have the potential to induce DNA strand breaks and chromosomal damage, but not gene mutations. No clear correlation was observed between the physico-chemical properties of TiO2 particles and the outcome of either in vitro or in vivo genotoxicity assays. A concern for genotoxicity of TiO2 particles that may be present in E 171 could therefore not be ruled out. Several modes of action for the genotoxicity may operate in parallel and the relative contributions of different molecular mechanisms elicited by TiO2 particles are not known. There was uncertainty as to whether a threshold mode of action could be assumed. In addition, a cut-off value for TiO2 particle size with respect to genotoxicity could not be identified. No appropriately designed study was available to investigate the potential carcinogenic effects of TiO2 NPs. Based on all the evidence available, a concern for genotoxicity could not be ruled out, and given the many uncertainties, the Panel concluded that E 171 can no longer be considered as safe when used as a food additive.
2021
2021
2021
Norsk institutt for naturforskning (NINA)
2021
Overvåking av langtransporterte atmosfæriske miljøgifter i luft og nedbør, årsrapport 2020.
Denne rapporten inkluderer miljøovervåkningsdata fra 2020 og tidstrender for programmet Langtransporterte atmosfæriske miljøgifter. Resultatene omfatter 200 organiske miljøgifter (regulerte og ennå ikke regulerte), 11 tungmetaller og et utvalg organiske kjemikalier som potensielt er av bekymring for Arktisk miljø.
NILU
2021
Micronucleus assay applied to advanced in vitro lung models at ALI for nanotoxicity assessment
Elsevier
2021
The influence of probe spacing and probe bias in a double Langmuir probe setup
Multi-needle Langmuir probes are mounted on satellites and sounding rockets for high-frequency characterization of plasma in the ionosphere. Mounted on a spacecraft, the recorded probe current often differs from expected results. In this paper, we perform a numerical study using a particle in cell model to see how the spacing between the individual probes used in a multi-needle setup influences the measured current. We also study how the applied probe bias voltage can contribute to deviations. In our study, we use realistic electron temperatures and electron densities for the relevant part of the ionosphere. However, the results should be generally applicable and valid for other space environments as well as for laboratory Langmuir probe applications. From our study, we can see that when the distance is short, less than two Debye lengths, the current is highly affected, and we can see deviations of more than 60% compared to a single probe setup.
AIP Publishing (American Institute of Physics)
2021
2021
Calibration of CO, NO2, and O3 Using Airify: A Low-Cost Sensor Cluster for Air Quality Monitoring
MDPI
2021
2021
2021
Introducing a nested multimedia fate and transport model for organic contaminants (NEM)
Some organic contaminants, including the persistent organic pollutants (POPs), have achieved global distribution through long range atmospheric transport (LRAT). Regulatory efforts, monitoring programs and modelling studies address the LRAT of POPs on national, continental (e.g. Europe) and/or global scales. Whereas national and continental-scale models require estimates of the input of globally dispersed chemicals from outside of the model domain, existing global-scale models either have relatively coarse spatial resolution or are so computationally demanding that it limits their usefulness. Here we introduce the Nested Exposure Model (NEM), which is a multimedia fate and transport model that is global in scale yet can achieve high spatial resolution of a user-defined target region without huge computational demands. Evaluating NEM by comparing model predictions for PCB-153 in air with measurements at nine long-term monitoring sites of the European Monitoring and Evaluation Programme (EMEP) reveals that nested simulations at a resolution of 1° × 1° yield results within a factor of 1.5 of observations at sites in northern Europe. At this resolution, the model attributes more than 90% of the atmospheric burden within any of the grid cells containing an EMEP site to advective atmospheric transport from elsewhere. Deteriorating model performance with decreasing resolution (15° × 15°, 5° × 5° and 1° × 1°), manifested by overestimation of concentrations across most of northern Europe by more than a factor of 3, illustrates the effect of numerical diffusion. Finally, we apply the model to demonstrate how the choice of spatial resolution affect predictions of atmospheric deposition to the Baltic Sea. While we envisage that NEM may be used for a wide range of applications in the future, further evaluation will be required to delineate the boundaries of applicability towards chemicals with divergent fate properties as well as in environmental media other than air.
Royal Society of Chemistry (RSC)
2021
2021
Ftalater er organiske stoffer som hovedsakelig brukes til å gjøre plast mykere, særlig i PVC. Produksjonen av disse forbindelsene er ikke regulert på globalt nivå. Vi undersøkte nivåer av 12 ftalater i fett/spekk fra blåhval, finnhval, grønlandshval og isbjørn fra norsk Arktis. I tillegg målte vi nivåer av nedbrytningsprodukter av ftalater i plasma fra isbjørn. Bis(2-etylhexyl) ftalat (DEHP) var den eneste ftalat-forbindelsen som ble kvantifisert i prøvene. DEHP var til stede i de fleste hvalprøvene og nivåene i blå- og finnhvalspekk var lik nivåer av kjente miljøgifter som PCBer og organiske plantevernmidler. Nedbrytningsprodukter av ftalater ble funnet i lave konsentrasjoner i noen få isbjørnprøver. I tillegg undersøkte vi ftalaters potensial til å forstyrre finnhvalenes kjernereseptorer. Kjernereseptorer er proteiner som regulerer gener. De studerte reseptorene er viktige for å regulere blant annet metabolisme, stressresponser og energibalanse. Vi fant at DEHP både kan øke og hemme aktiviteten til skjoldbruskkjertelhormonreseptor, men da i høyere konsentrasjoner enn det som ble målt i spekk-/fettprøvene. Siden de studerte finnhvalreseptorene er helt eller nesten like de som finnes hos mange andre arter inkludert blåhval, vågehval, spekkhoggere, hvithval, isbjørn og mennesker, er resultatene også relevante for disse artene. Dette studiet bidrar til å øke kunnskapen om plastrelaterte stoffer og deres potensial til å forstyrre hormonsystemet hos marine pattedyr fra norsk Arktis.
Elsevier
2021
2021
2021