Fant 9747 publikasjoner. Viser side 357 av 390:
2023
2023
Deposition of sulfur and nitrogen in Norway 2017-2021
Norwegian Meteorological Institute
2023
It is of considerable interest to identify chemicals which may represent a hazard and risk to environmental and human health in remote areas. The OECD POV and LRTP Screening Tool (“The Tool”) for assessing chemicals for persistence (P) and long-range transport potential (LRTP) has been extensively used for combined P and LRTP assessments in various regulatory contexts, including the Stockholm Convention (SC) on Persistent Organic Pollutants (POPs). The approach in The Tool plots either the Characteristic Travel Distance (CTD, in km), a transport-oriented metric, or the Transfer Efficiency (TE, in %), which calculates the transfer from the atmosphere to surface compartments in a remote region, against overall persistence (POV). For a chemical to elicit adverse effects in remote areas, it not only needs to be transported and transferred to remote environmental surface media, it also needs to accumulate in these media. The current version of The Tool does not have a metric to quantify this process. We screened a list of >12 000 high production volume chemicals (HPVs) for the potential to be dispersed, transferred, and accumulate in surface media in remote regions using the three corresponding LRTP metrics of the emission fractions approach (EFA; ϕ1, ϕ2, ϕ3), as implemented in a modified version of The Tool. Comparing the outcome of an assessment based on CTD/TE and POV with the EFA, we find that the latter classifies a larger number of HPVs as having the potential for accumulation in remote regions than is classified as POP-like by the existing approach. In particular, the EFA identifies chemicals capable of accumulating in remote regions without fulfilling the criterion for POV. The remote accumulation fraction of the EFA is the LRTP assessment metric most suited for the risk assessment stage in Annex E of the SC. Using simpler metrics (such as half-life criteria, POV, and LRTP–POV combinations) in a hazard-based assessment according to Annex D is problematic as it may prematurely screen out many of the chemicals with potential for adverse effects as a result of long-range transport.
Royal Society of Chemistry (RSC)
2023
Environmental pollutants in the terrestrial and urban environment 2022
Samples of soil, earthworm, fieldfare egg, brown rat liver, spanish slug, house dust and cat liver from the urban terrestrial environment in the Oslo area were analysed for several different groups of environmental pollutants. Biota-soil accumulation was calculated from soil to earthworm from the same location, and biomagnification-potential was estimated based on detected data for relevant predator-prey pairs from the same location.
NILU
2023
2023
2023
Radiocarbon (14C) analysis of carbonaceous aerosols is used for source apportionment, separating the carbon content into fossil vs. non-fossil origin, and is particularly useful when applied to subfractions of total carbon (TC), i.e. elemental carbon (EC), organic carbon (OC), water-soluble OC (WSOC), and water-insoluble OC (WINSOC). However, this requires an unbiased physical separation of these fractions, which is difficult to achieve. Separation of EC from OC using thermal–optical analysis (TOA) can cause EC loss during the OC removal step and form artificial EC from pyrolysis of OC (i.e. so-called charring), both distorting the 14C analysis of EC. Previous work has shown that water extraction reduces charring. Here, we apply a new combination of a WSOC extraction and 14C analysis method with an optimised separation that is coupled with a novel approach of thermal-desorption modelling for compensation of EC losses. As water-soluble components promote the formation of pyrolytic carbon, water extraction was used to minimise the charring artefact of EC and the eluate subjected to chemical wet oxidation to CO2 before direct 14C analysis in a gas-accepting accelerator mass spectrometer (AMS). This approach was applied to 13 aerosol filter samples collected at the Arctic Zeppelin Observatory (Svalbard) in 2017 and 2018, covering all seasons, which bear challenges for a simplified 14C source apportionment due to their low loading and the large portion of pyrolysable species. Our approach provided a mean EC yield of 0.87±0.07 and reduced the charring to 6.5 % of the recovered EC amounts. The mean fraction modern (F14C) over all seasons was 0.85±0.17 for TC; 0.61±0.17 and 0.66±0.16 for EC before and after correction with the thermal-desorption model, respectively; and 0.81±0.20 for WSOC.
2023
2023
2023
Forskerne finner mikroplast i luft ved hjelp av aluminiumsbøtter og 600 graders varme
Norges forskningsråd
2023
Rapid identification of in vitro cell toxicity using an electrochemical membrane screening platform
This study compares the performance and output of an electrochemical phospholipid membrane platform against respective in vitro cell-based toxicity testing methods using three toxicants of different biological action (chlorpromazine (CPZ), colchicine (COL) and methyl methanesulphonate (MMS)). Human cell lines from seven different tissues (lung, liver, kidney, placenta, intestine, immune system) were used to validate this physicochemical testing system. For the cell-based systems, the effective concentration at 50 % cell death (EC50) values are calculated. For the membrane sensor, a limit of detection (LoD) value was extracted as a quantitative parameter describing the minimum concentration of toxicant which significantly affects the structure of the phospholipid sensor membrane layer. LoD values were found to align well with the EC50 values when acute cell viability was used as an end-point and showed a similar toxicity ranking of the tested toxicants. Using the colony forming efficiency (CFE) or DNA damage as end-point, a different order of toxicity ranking was observed. The results of this study showed that the electrochemical membrane sensor generates a parameter relating to biomembrane damage, which is the predominant factor in decreasing cell viability when in vitro models are acutely exposed to toxicants. These results lead the way to using electrochemical membrane-based sensors for rapid relevant preliminary toxicity screens.
Elsevier
2023
Transboundary particulate matter, photo-oxidants, acidifying and eutrophying components
Norwegian Meteorological Institute
2023
The Sub-Millimetre Radiometer (SMR) on board the Odin satellite provides almost 20 years of nitric oxide (NO) measurements in the mesosphere and lower thermosphere (MLT) at equatorial crossing local solar times (LSTs) of 6 AM and 6 PM. In this study, we use Odin/SMR observations to estimate how lower thermospheric NO mixing ratios at low latitudes are affected by solar nonmigrating tides. Most of the previous studies based on satellite data have focused on the signatures of diurnal tides in the MLT and above, while we concentrate here on nonmigrating semidiurnal tides. To study the contribution of these tides to NO mixing ratio variations, we average pairs of NO measurements along ascending and descending orbital tracks at 107 km altitude over latitudes between −40°and +40°. We consider monthly climatologies of these pair-averages and analyse residuals with respect to their zonal mean. In this way, it is possible to study the effect of nonmigrating even-numbered tidal components, albeit there is a non-tidal component arising largely from quasi-stationary planetary waves. Spectral wave amplitudes are extracted using a Fourier transform as function of (apparent) zonal wavenumber with a focus around −30°, −20°and 30°latitudes. From our analysis, it appears that the semidiurnal (apparent) zonal wavenumber 4 arising from the SW6 and SE2 tides is dominant close to the equator (e.g., at −20°), except during some boreal summer months (June, July, August). On the other hand, wave-1 plays a more prominent role at subtropical latitudes, especially in the southern hemisphere, where it surpasses wave-4 during 7 months (March and May-to-October) at −30°. There is little observational evidence to date documenting the presence of the semidiurnal nonmigrating tides in NO in the low-latitude MLT. Our results hence provide one of the first evidences of the climatological signature of these tides in NO, in an altitude range that remains poorly observed.
Elsevier
2023
2023
Screening Programme 2022. New environmental pollutants.
Norsk institutt for vannforskning
2023
2023
2023