| 1. |
- Azeem, Hafiz Abdul, et al.
(författare)
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Towards the isolation and estimation of elemental carbon in atmospheric aerosols using supercritical fluid extraction and thermo-optical analysis
- 2017
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 409:17, s. 4293-4300
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Tidskriftsartikel (refereegranskat)abstract
- Air-starved combustion of biomass and fossil fuels releases aerosols, including airborne carbonaceous particles, causing negative climatic and health effects. Radiocarbon analysis of the elemental carbon (EC) fraction can help apportion sources of its emission, which is greatly constrained by the challenges in isolation of EC from organic compounds in atmospheric aerosols. The isolation of EC using thermo-optical analysis is however biased by the presence of interfering compounds that undergo pyrolysis during the analysis. EC is considered insoluble in all acidic, basic, and organic solvents. Based on the property of insolubility, a sample preparation method using supercritical CO2 and methanol as co-solvent was developed to remove interfering organic compounds. The efficiency of the method was studied by varying the density of supercritical carbon dioxide by means of temperature and pressure and by varying the methanol content. Supercritical CO2 with 10% methanol by volume at a temperature of 60 °C, a pressure of 350 bar and 20 min static mode extraction were found to be the most suitable conditions for the removal of 59 ± 3% organic carbon, including compounds responsible for pyrolysis with 78 ± 16% EC recovery. The results indicate that the method has potential for the estimation and isolation of EC from OC for subsequent analysis methods and source apportionment studies.
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| 2. |
- Bernhardsson, Christian, et al.
(författare)
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Environmental radiation baseline around the Belarusian nuclear power plant – assessments in Belarus and Lithuania
- 2023
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 16<sup>th</sup> International Conference on Medical Physics - Proceedings of the 16<sup>th</sup> International Conference on Medical Physics. - 1822-5721. ; , s. 121-125
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Konferensbidrag (refereegranskat)abstract
- Prior to the operation of the first Belarussian nuclear power plant (BelNPP), the baseline of the radiation environment was determined within a radius of about 30 km from BelNPP. This independent assessment was carried out during two expeditions in 2019. In 2022, a similar survey was carried out (during the initialoperation of BelNPP) on the Lithuanian side of the boarder. Here we present the overall project and some general results of the baseline assessments.
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| 3. |
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| 4. |
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| 5. |
- Bernhardsson, Christian, et al.
(författare)
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Radiological environmental monitoring at the ESS facility – Annual report 2020
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Results from the radiological environmental monitoring of the European Spallation Source (ESS) are presented for year 2020.Among the 63 environmental samples analysed for gamma emitting radionuclides, no elevated levels of anthropogenic radioactivity were observed. All samples (except two samples of lichen) had activity concentrations below the MDA for the natural radionuclides as well as 137Cs, and normal levels of 40K. In sewage sludge, detectable levels of 177Lu and 1311 were observed in samples that were measured within one week after sampling.Mobile gamma spectrometry surveys were carried out around ESS and MAX IV (when operating at high frequency during a test run). No deviating radiation levels were observed.The samples analysed for their 3H activity concentration (120 samples) were generally below the detection limit using the current procedure, instrumentation and analysis time (MDA typically 1.6 Bq L-1). The results show no evidence of any local contamination of 3H in Lund during 2020.The 14C data in the 26 samples of grass, fruits, berries, crops, milk, honey and meat of in the Lund area and in southern Sweden is consistent with the declining 14C specific activity in atmospheric CO2. Seasonal variations were observed in the 14C data. No evidence of anthropogenic 14C contamination in the Lund area was noted during 2020.The report presents the first base-line measurements of 129I (10 samples) in the ESS environmental monitoring programme. The 129I activity concentrations ranged between (3.18 ± 0.20)∙1011 atoms/kg d.w. for grass and (1.31 ± 0.03)∙1013 atoms/kg d.w. for moss. These values are in the expected range.
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| 6. |
- Bernhardsson, Christian, et al.
(författare)
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ZERO POINT ASSESSMENT OF THE RADIATION ENVIRONMENT – EXAMPLES OF A PROGRAM APPLIED IN SWEDEN (ESS) AND IN BELARUS (BELNPP)
- 2019
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Ingår i: MEDICAL PHYSICS IN THE BALTIC STATES : Proceedings of the 14th International Conference on Medical Physics - Proceedings of the 14th International Conference on Medical Physics. ; , s. 85-88
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Konferensbidrag (refereegranskat)abstract
- Before commissioning of a nuclear facility it is important to determine the baseline of the radiation environment. Such baseline or Zero Point assessments can only,and uniquely, be made before start of operation of the facility and will serve several purposes when the facility is in operation. Here we report on the planning and implementation of such a Zero Point program for achieving high reproducibility and effectiveness of the assessments around two nuclear installations.
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| 7. |
- Edsfeldt, Andreas, et al.
(författare)
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Human Atherosclerotic Plaque Progression Is Dependent on Apoptosis According to Bomb-Pulse 14C Dating
- 2021
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Ingår i: JACC: Basic to Translational Science. - : Elsevier BV. - 2452-302X. ; 6:9-10, s. 734-745
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Tidskriftsartikel (refereegranskat)abstract
- Individuals with rapidly progressing atherosclerotic plaques are at higher risk of experiencing acute complications. Currently, we lack knowledge regarding factors in human plaque that cause rapid progression. Using the 14C bomb-pulse dating method, we assessed the physical age of atherosclerotic plaques and which biological processes were associated with rapidly progressing plaques. Interestingly, increased apoptosis was the main component associated with a young physical plaque age, reflecting rapid plaque progression. Our findings in combination with recent advances in imaging techniques could guide future diagnostic imaging strategies to identify rapidly progressing plaques or therapeutic targets, halting plaque progression.
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| 9. |
- Eriksson Stenström, Kristina, et al.
(författare)
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Assessment of sediment sampling techniques for ESS environmental monitoring programme
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Radionuclides released and discharged into the environment from nuclear and other radiation-related facilities, such as the European Spallation Source (ESS), may accumulate in aquatic bottom sediments. Sediments should therefore, as recommended by the IAEA, be monitored regularly. This report describes the setting up of a methodology for zero-point assessments of the radiation levels in sediments of relevance for possible future releases from the ESS.Two types of sediment sampling devices have been tested: a grab sampler of the Lamotte type, and a stationary bottom trap consisting of a 5-L bucket placed on the bottom of a pond. The Lamotte grab sampler worked well in the absence of obstacles such as vegetation and stones. Sampling from boat may be advantageous in finding suitable sampling spots for the grab sampler. The stationary bottom trap, tested for more than two years at one of the ponds at the ESS facility, proved functional. To be certain to obtain sufficient sediment during collection period of one year, we recommend using three 5-L buckets per pond. The bottom trap is most likely not suitable for sampling in rivers with flowing water.For the sample preparation, sieving the sediment in a laboratory was found to be more efficient and more convenient compared to sieving at the sampling site. Freeze-drying was found superior, in terms of efficiency and dried sample texture, to drying the sediment in open air. Measurements of total carbon, total nitrogen, and the carbon to nitrogen ratio proved to have the potential to provide relevant information about the sources of the sediment. The results of gamma-ray spectrometry confirmed sediments as a useful indicator of radionuclides, with activity concentrations above the MDA levels for all reported radionuclides and samples, except for one site. Gamma-ray spectrometry measurements on the samples can provide information on local elevated levels of anthropogenic radionuclides and add information to the sources of the sediment itself.
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| 10. |
- Eriksson Stenström, Kristina, et al.
(författare)
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Environmental levels of radiocarbon in Lund, Sweden, prior to the start of the European Spallation Source
- 2022
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Ingår i: Radiocarbon. - 0033-8222. ; 64:1, s. 51-56
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Tidskriftsartikel (refereegranskat)abstract
- The European Spallation Source (ESS) is a neutron-based research facility under construction in Lund in southern Sweden. The spallation reactions will generate not only the desired neutrons, but also many radioactive byproducts, including 14C. As part of the licensing process, and as recommended by the IAEA, various preoperational studies are being carried out, including mapping the “zero-point” radiation environment around the site. As the city of Lund hosts several facilities using 14C-labeled substances, and since temporary and local 14C contamination have been observed in the past, 14C mapping is an important part of these baseline assessments. We here present a summary of 14C levels in various terrestrial environmental samples in Lund and in southern Sweden during the years 2012 to 2020. These environmental F14C do not display significantly elevated levels compared to sites located remote from Lund. We also describe a local 14C contamination event that was detected at the Lund Radiocarbon Dating Laboratory in 2009. Horse-chestnut leaves collected close to the laboratory exhibited F14C values of up to ∼25% above the clean air background. Elevated values of F14C were also found in a short tree-ring series, especially in 2007. The source of this contamination was identified and successfully removed.
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