| 1. |
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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. |
- Chamizo, E., et al.
(författare)
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Insights into the Pu isotopic composition (239Pu, 240Pu, and 241Pu) and 236U in marshland samples from Madagascar
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 740
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Tidskriftsartikel (refereegranskat)abstract
- This work provides new insights into the presence of 239Pu, 240Pu, 241Pu, and 236U in the Southern Hemisphere through the study of peat bog cores from marshlands in Madagascar (19°S). 210Pb, 238Pu and 239+240Pu activities were characterized by alpha spectrometry in previous studies. Here, Pu from alpha-spectrometry discs corresponding to 10 peat-bog cores (85 samples) was reassessed for the aim of completing its isotopic composition (239Pu, 240Pu, and 241Pu) by Accelerator Mass Spectrometry. In addition, 236U was studied in a single core exhibiting unusually low 240Pu/239Pu ratios. Integrated 240Pu/239Pu atom ratios in the single cores ranged above and below the (0–30°S) fallout average ratio, 0.173 ± 0.027, from 0.126 ± 0.003 to 0.206 ± 0.002, without a regional pattern, thereby demonstrating the heterogeneous distribution of the 239Pu and 240Pu signal. However, such a variability was not observed for 241Pu/239Pu, ranging from (6 ± 1) · 10−4 to (11 ± 1) · 10−4 and consistently below the (0–30°S) fallout ratio of (9.7 ± 0.3) · 10−4 (2012). The integrated 236U/239Pu atom ratio in the studied core, 0.147 ± 0.005, was also significantly lower than the values reported for the global fallout in the Northern Hemisphere, in the 0.20–0.23 range. Our results point out to stratospheric fallout as the main source of both 236U and 241Pu at the studied site, whereas 239Pu and 240Pu signals show the influence of tropospheric fallout from the low-yield tests conducted in Australia (1952–1958) by United Kingdom and in French Polynesia (1966–1975) by France despite the long relative distances (i.e. about 15,000 and 8500 km). It was also demonstrated that a representative number of samples is necessary in order to assess Pu contamination and its various origins in a specific region in the Southern Hemisphere due to the heterogeneous distribution, and results based on single sample analysis should be interpreted with caution. © 2020 Elsevier B.V.
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| 8. |
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| 9. |
- 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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| 10. |
- Eriksson Stenström, Kristina, et al.
(författare)
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Identifying radiologically important ESS-specific radionuclides and relevant detection methods
- 2020
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Bok (refereegranskat)abstract
- The European Spallation Source (ESS) is under construction in the outskirts of Lund in southern Sweden. When ESS has entered the operational phase in a few years, an intense beam of high-energy protons will not only produce the desired spallation neutrons from a large target of tungsten, but a substantial number of different radioactive by-products will also be generated. A small part of these will be released to the environment during normal operation. During an accident scenario, a wide range of gases and aerosols may be released from the tungsten target. The palette of radionuclides generated in the ESS target will differ from that of e.g. medical cyclotrons or nuclear power plants, thus presenting new challenges e.g. in the required environmental monitoring to ensure that dose limits to the public are not exceeded. This project (SSM2018-1636), financed by the Swedish Radiation Safety Authority (SSM), aimed to strengthen competence at Lund University for measurement and analysis of ESS-specific radionuclides. First, an extensive literature review, including modelling as well as experimental analyses, of ESS-relevant radionuclides was performed. We found that radionuclide production in particle accelerators is well-known, while experience with tungsten targets is very limited. As a second part of the project, an independent simplified model of the ESS target sector for the calculations of radionuclide production in the ESS tungsten target was developed using the FLUKA code. We conclude that we have a fairly good agreement with results of other authors, except for 148Gd, and that the calculated radionuclide composition is sensitive to the nuclear interaction models used.In the third part of the project, known environmental measurement technologies for various ESS-relevant radionuclides were reviewed, focussing on pure difficult-to-measure alpha- and beta-emitters. Liquid scintillation counting (LSC) is a suitable technique e.g. for the important beta emitters 3H, 14C, 35S, 31P and 33P. Several ESS radionuclides of relevance for dose estimates have never been investigated by environmental analytical techniques, due to their absence in the normal environment. Alpha spectrometry seems promising for the analysis of alpha-emitting lanthanides, in particular for 148Gd. Among the many types of mass spectrometry techniques, ICP-MS (inductively coupled plasma mass spectrometry) and AMS (accelerator mass spectrometry) seem to be the most suitable for the analysis of long-lived ESS radionuclides in environmental samples (e.g. 243Am and possibly lanthanides for ICP-MS and 10Be, 14C, 32Si, 36Cl, 60Fe and 129I for AMS).Three experimental parts were performed during the project, related to initiation of radioactivity measurements of aerosols at Lund University, mapping of environmental tritium in the Lund area, and establishment of a method to measure tritium in urine followed by a study of tritium in persons presently living or working in Lund. Aerosols were collected at a rural background station (Hyltemossa near Perstorp, northern Skåne) using a high-volume aerosol sampler with automatic filter change (DHA-80, Digitel). Gamma spectrometry measurements of 7Be agreed rather well with results from a nearby air monitoring station (SSM/FOI). Tritium (radioactive hydrogen) is expected to dominate the source term from the ESS target station to the environment. We have performed several investigations to monitor the current situation of tritium in Lund using LSC: the matrices investigated included air humidity, precipitation, pond water, indoor air at one accelerator facility and urine from the general public as well as from persons who may be occupationally exposed to tritium. Environmental tritium was generally very low (<3.4 Bq L-1), with somewhat higher concentration in the springtime than during the rest of the year. Tritium in the vast majority of the 55 urine samples was also very low: only a few exposed workers were found to have up to 11 Bq L-1 in their urine, which still is very low compared to e.g. reactor workers. Suggestions for further actions and work related to measurement and analysis of ESS relevant radionuclides are presented.
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| 11. |
- Eriksson Stenström, Kristina, et al.
(författare)
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PREOPERATIONAL ASSESSMENT OF 14C IN THE VINICINITY OF THE BELARUSIAN NUCLEAR POWER PLANT
- 2021
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 15th International Conference - Proceedings of the 15th International Conference. - 1822-5721. ; , s. 133-137
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Konferensbidrag (refereegranskat)abstract
- As part of an independent assessment of the preoperational radiation environment around the Ostrovets nuclear power plant in Belarus, grass and foodstuffs were collected in 2019 for 14C analysis. The preoperational 14C specific activities in the Ostrovets region were shown to be similar to that of European data from other uncontaminated sites.
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| 12. |
- Eriksson Stenström, Kristina, et al.
(författare)
-
Radiological environmental monitoring at the ESS facility – Annual report 2021
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Results from the radiological environmental monitoring of the European Spallation Source (ESS) are presented for 2021. Previous zero-point assessments (2017-2020) have mainly focussed on terrestrial samples. New sample types for 2021 include a sediment sample from a pond at the ESS and brown seaweed (Fucus) from Lomma bay and from the east coast of Scania (Skillinge). For gamma-emitting radionuclides, increased levels of anthropogenic radioactivity (177Lu and 131I) originating from hospital use, were only observed in sewage sludge samples. For tritium, the majority of the samples had activity concentrations that were below the minimum detectable activity (MDA) of 1.62 Bq l-1. Expected environmental levels, without any evidence of local contamination, were also seen in the 14C data.
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| 13. |
- Frost, Robert, et al.
(författare)
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Development of a Pelletron-based compact neutron source : At the Nuclear Applications Laboratory, Lund University
- 2023
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Ingår i: Journal of Neutron Research. - 1023-8166. ; 24:3-4, s. 281-287
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Tidskriftsartikel (refereegranskat)abstract
- The Applied Nuclear Physics Group at Lund University is constructing a prototype CANS (Compact Accelerator-driven Neutron Source). The CANS is based around a 3 MV, single-ended, Pelletron accelerator, which is used to impinge a 2.8 MeV deuterium beam into a beryllium target. The anticipated neutron production will be on the order of 1010 n/s in 4π sr. A further upgrade to the ion source of the Pelletron is expected to increase neutron production to 1011 n/s. Neutron energies will be up to 9 MeV with peak emission at ∼5 MeV. Shielding and moderation will be provided by a large water tank surrounding the target, with three exit ports to allow neutrons of different energies to be directed to experiments. The design is supported by simulation results which predict fast-neutron fluxes of 9×104 to 5×106 n/cm2/s, and thermal-neutron fluxes of 1×104 to 5×104 n/cm2/s to be readily obtainable with a 10 µA deuteron beam.
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| 14. |
- Martinsson, Johan, et al.
(författare)
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Experimental wildfire induced mobility of radiocesium in a boreal forest environment
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 792
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Tidskriftsartikel (refereegranskat)abstract
- Wildfires are expected to increase with warmer climate, which can contribute to the mobility and the resuspension of long-lived and potentially hazardous radionuclides. The release of 137Cs during combustion of dried litter, forest floor organic soil, and peat was investigated in a small-scale experimental set-up. Combustion conditions were varied to simulate different wildfire scenarios, and the fuels were dried organic material collected in a boreal environment of Sweden that was contaminated following the Chernobyl accident in 1986. The combustion-related release of 137Cs to the air was on average 29% of the initial fuel content, while 71% of the initial 137Cs remained in the ashes after the combustion. Peat and forest soil had the highest releases (39% and 37%, respectively), although these numbers should be viewed as potential releases since authentic wildfire combustion of these fuels are usually less effective than observed in these experiments. These results indicates that the 137Cs has migrated downwards in the organic material, which imply potentially significantly more 137Cs emissions in severe wildfires with intense combustion of the organic vertical profile in peatbogs and forests. More 137Cs tended to be released during intense and efficient combustion processes, although no significant differences among combustion intensities were observed. The generated experimental data was used in an emission scenario to investigate the possible range in 137Cs emissions from a wildfire. Our study shows that a severe wildfire in a contaminated area of 10,000 ha could potentially release up to 7 TBq of 137Cs. This is the first laboratory study to investigate 137Cs release upon varying combustion conditions using real fallout contaminated organic material obtained from a boreal environment.
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| 15. |
- Martinsson, Johan, et al.
(författare)
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Influence of variable oxygen concentration on the combustion derived release of radiocesium from boreal soil and peat
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 815
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Tidskriftsartikel (refereegranskat)abstract
- Radiocesium, 137Cs, is one of the most common and dispersed human-made radionuclides. Substantial stocks of 137Cs are stored in organic layers, like soils and peat, as a consequence of nuclear weapons fallout and accidental releases. As climate warming progresses these organic layers are subject to enhanced risks of wildfires, especially in the vast boreal biome of the northern hemisphere. Reemission of 137Cs to the atmosphere is therefore presumed to increase. Here, we experimentally investigated the emissions and redistribution of 137Cs in smoldering fires of boreal soil and peat by varying the oxygen concentration during combustion. For both soil and peat, significantly more 137Cs was released through flaming combustion in 21% O2 (50% and 31%, respectively) compared to smoldering in reduced O2 environments (14% and 8%, respectively). The residual ashes were heavily enriched (>100%) in 137Cs. Hence, after a wildfire induced volatilization of 137Cs, there exists further pathways of 137Cs enriched ash to proliferate in the environment. These results serve as a link between wildfire combustion conditions and the mobility of the 137Cs inventory found in ground fuels of the boreal environment and can be valuable for radiological risk assessments in a warmer and a more nuclear energy reliant world.
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| 16. |
- Martinsson, Johan, et al.
(författare)
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On the Relationship of Biogenic Primary and Secondary Organic Aerosol Tracer Compounds on the Aethalometer Model Parameters
- 2020
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 2071-1409 .- 1680-8584. ; 20:12, s. 2654-2668
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Tidskriftsartikel (refereegranskat)abstract
- The aethalometer model has shown to offer a fast, inexpensive and robust method for source apportionment. The method relies on aerosol light absorption attribution, mass balance of the total carbon and results in a fraction of unaccounted, residual carbon that has been associated to biogenic carbon due to its presumably non-light absorbing properties. This residual carbon and its relation to tracers of biogenic primary and secondary organic aerosol was investigated at a rural measurement station in Sweden. Special focus is devoted to 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a second-generation oxidation compound in biogenic secondary organic aerosols. The results show that the residual carbon and the biogenic tracers show a high degree of correlation and that the tracers were highly seasonally dependent with largest carbon contributions during summer. MBTCA showed positive correlation with the aethalometer model derived absorption coefficients from fossil fuel carbonaceous aerosol, stressing the suspicion that biogenic aerosol might be falsely apportioned to fossil fuel carbon in the aethalometer model. MBTCA showed an increasing degree of correlation with higher aethalometer absorption coefficient wavelengths. However, spectrophotometric analysis revealed that the ambient concentrations of MBTCA are most likely to low to give a significant response in the aethalometer. These results support the application of MBTCA as a molecular tracer for biogenic secondary organic aerosol and indicates that a large fraction of the aethalometer model residual carbon is of biogenic origin. Future studies should investigate the light absorbing properties of precursor monoterpenes such as α-pinene, their oxidation products and eventual influence on the aethalometer model.
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| 17. |
- Mattsson, Sören, et al.
(författare)
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Gadolinium in coastal waters -Time trends and possible sources
- 2023
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Ingår i: Medical Physics in the Baltic States 2023 : Proceedings of the 16th International Conference on Medical Physics - Proceedings of the 16th International Conference on Medical Physics. ; , s. 112-114
-
Konferensbidrag (refereegranskat)abstract
- Samples of Fucus serratus and Fucusvesiculosus taken in Swedish coastal waters have beenanalysed for Gd by ICP-MS. The results for one site withfrequent sampling show significantly increasing levelsduring the last 30 years, most likely a result of theincreasing use of Gd-containing contrast agents for MR-imaging at hospitals and other health care institutions.Samples taken at the west-, south- and east-coast in 2020show considerable variation in Gd-concentration fromsite to site with highest level in northern Kattegat.
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| 18. |
- Mattsson, Sören, et al.
(författare)
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Long-time variations of radionuclides and metals in the marine environment of the Swedish west-coast studied using brown algae : (Fucus serratus and Fucus vesiculosus)
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The support from SSM has made it possible to continue collecting brown algaefrom the place on the Swedish west coast where regular collections began asearly as 1967. The support has also enabled more extensive analyses ofpreviously collected material than was possible before. This applies to bothsupplementary analyses of previously reported radionuclides and analysis ofnew ones. The project has also enabled a start of more comprehensive analysesof the overall results. This has provided better information about long-termprocesses and seasonal variations for different radionuclides in both toothedwrack (Fucus serratus) and bladderwrack (Fucus vesiculosus). What is new isthat the sample material has now also been used to analyse metals, both thosewith known toxic effects such as lead, cadmium and mercury, as well as thosethat are of interest in assessing transport routes for radionuclides generated innew radiation sources, such as gadolinium isotopes from the EuropeanSpallation Source (ESS).Regarding the long-term development of various radionuclides in the marineenvironment on the Swedish west coast, the studies show rapidly increasinglevels of iodine-129, decreasing levels of cesium-137, technetium-99 andplutonium-239+240. The carbon-14 analyses suggest a continued inflow of thisradionuclide from the North Sea. The study also shows that the brown algaecould be important for the monitoring of emissions of naturally occurringradioactive materials (NORM) from the offshore oil and gas industry bysystematically studying long-term and seasonal variations of the content ofradium-228 and in the future also radium- 226 and lead-210. Interesting andhitherto unexplained variations in the beryllium-7 content in Fucus have beenmade. The tritium content in Fucus and in seawater has been analysed in alimited number of samples from 2020. No levels beyond the expected normalambient level for tritium have been found.During the 10-year period 2011-2020, there was a doubling of the levels of leadand nickel and a 50% increase in the levels of cadmium and cobalt in Fucus. Formercury a 10-fold decrease is registered between 2011 and 2016 and then adoubling of the concentration between 2016 and 2020. The decreasing trend formercury probably indicates an effect of the gradual phasing out of mercury inSweden and other countries. However, some businesses and companies have anexemption for continued use. For gadolinium there is an increase with a factor ofaround 5 from 2011 to 2020, most likely explained by the increased use ofgadolinium-containing contrast agents in magnetic resonance imaging inhealthcare.
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| 19. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
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Evaluation of the region-specific risks of accidental radioactive releases from the European Spallation Source
- 2021
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 15th International Conference on Medical Physics - Proceedings of the 15th International Conference on Medical Physics. - 1822-5721. ; , s. 142-146
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Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) is a neutron research facility under construction in southern Sweden. The facility will produce a wide range ofradionuclides that could be released into the environment. Some radionuclides are of particular concern such as the rare earth gadolinium-148. In this article, the local environment was investigated in terms of food production and rare earth element concentration in soil. The collected data will later be used to model thetransfer of radioactive contaminations from the ESS.
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| 20. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
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How to detect radionuclides specific to the European Spallation Source in soil samples?
- 2023
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Ingår i: Medical Physics in the Baltic States (2023) : Proceedings of the 16th International Conference on Medical Physics - Proceedings of the 16th International Conference on Medical Physics. ; , s. 115-120
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Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) is a neutron research facility under construction in southern Sweden. The facility will produce a wide range of radionuclides including 148Gd, 187W, 172Hf, 182Ta and 178nHf that could be released into the environment in an accident scenario. Detection limits for these contaminants in soil were estimated to be in the mg k-1 range for ICP-MS and <3 Bq per 200 ml soil for gamma-ray spectroscopy.
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| 21. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
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Investigation of the limits of detection for specific radionuclides in soil from the European Spallation Source (ESS) using radiometric and mass spectrometric methods
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This study provides information about the concentration of Tungsten (W), Hafnium (Hf) and Tantal (Ta) in the ESS soil and recommendations on the most appropriate sample preparation and measurement technique to assess contamination by these elements. The current levels of W, Hf and Ta measured in this study are in agreement with the estimated values from previous geological surveys. ICP MS showed low limits of detection for W, Hf and Ta and is thus an appropriate technique for environmental monitoring. However, the three metals are difficult to extract from soil and require the use of specific sample preparation methods (based on hydrofluoric acid for example). The transfer of stable W, Hf and Ta from soil to plant is poorly known and only a handful of publications can be found that are relevant to the plants grown around the ESS. The transfer of the radioisotopes of W, Hf and Ta in particular to animals (and man) is even less studied. However, the existing articles indicate a fast excretion of radio-W and radio-Ta while the excretion is slow for radio-Hf.The Minimum Detectable Activity (MDA) for gamma emitter released from the ESS facility will depend not only on the performances of the detection equipment but also on the composition of tungsten target at the time of the release. The determination of limits of detection of ESS related gamma emitters was performed using a strategy based on simulation of spectra. Semi-synthetic gamma spectra were obtained by combining real soil measurements with simulated data for mixtures of ESS radionuclides using the software Nucleonica. The simulation of 187W spectra was used as a proof of concept for the method. With this approach, it is possible to estimate limits of detection by gamma spectroscopy for a given target composition. The limits of detection of four relevant radionuclides were successfully determined for two different compositions of the ESS target and at three different activity concentrations in soil.
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| 22. |
- Pedehontaa-Hiaa, Guillaume, et al.
(författare)
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Layer‑by‑Layer Assemblies Based on a Cationic β‑Cyclodextrin Polymer: Chiral Stationary Phases for Open‑Tubular Electrochromatography
- 2015
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Ingår i: Chromatographia. - : Springer Science and Business Media LLC. - 0009-5893 .- 1612-1112. ; 78:7-8, s. 533-541
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Tidskriftsartikel (refereegranskat)abstract
- Non-covalent chiral stationary phases for open-tubular capillary electrochromatography (OT-CEC) were developed using polyelectrolyte multilayer (PEM) coatings. These chiral coatings were made by alternately flushing the separation capillary with cationic and anionic polymers using a polymer of trimethylammonium-β-CD (pCD+) as a chiral selector. The layer-by-layer construction was monitored by EOF measurements. To our knowledge, it is the first OT-CEC chiral stationary phase based on a layer-by-layer assembly including an ionic cyclodextrin polymer. The composition of PEM coating was optimized as regards chiral separation. Thus, the influence of the nature of the first adsorbed cationic polymer (pCD+, polyethyleneimine or poly(diallyldimethyl ammonium chloride)) and the influence of the anionic polymer (poly(sodium 4-styrenesulfonate), polycarboxymethyl-β-CD or chondroitin sulfate) were studied with regard to the apparent surface charge and the enantioselective properties of the coatings. Interactions between the studied enantiomers and the internal layers of the stationary phase were pointed out. We found that the optimal stationary phase was based on a pCD+/poly(sodium 4-styrenesulfonate)/pCD+ three-layer coating. This optimal coating was found to be stable as evidenced by the RSD of 2.2 % for the EOF values calculated from five independent analyses. It was effective for the chiral separation of both neutral and anionic solutes.
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| 23. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
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Region-specific radioecological evaluation of accidental releases of radionuclides from ESS
- 2021
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Bok (refereegranskat)abstract
- Gadolinium-148 is one of the radionuclides of most concern that will be produced in the tungsten target of the European Spallation Source (ESS), as a by-product of the spallation reaction used by the facility to produce neutrons. Since 148Gd a pure alpha emitter, it is both very radiotoxic and difficult to measure. With its half-life of 75 years, it will remain in the environment for a long time if released from the facility during normal operation or after an accident. There are still uncertainties regarding the amounts that actually will be produced by spallation in the tungsten targets of the facility. As Gd-148 does not occur naturally in the environment, there is no information available about its analysis in environmental samples but a few studies provide data from irradiated target material analysed by alpha spectroscopy or inductively coupled plasma mass spectrometry (ICP-MS). This report is a continuation of the SSM project as described in the SSM report 2020:08, entitled “Identifying radiologically important ESS-specific radionuclides and relevant detection methods” that focused on the ESS-related radionuclides that will be the most relevant to study and monitor in the environment as well as the analytical techniques to detect them. The present report focuses on the rare earth elements (REEs), including their radioactive isotopes, in particular Gd-148, and is intended to highlight the knowledge gaps that exist regarding their fate in the specific environment of the ESS area. In the first part of the report, the available literature on radioecological models was reviewed, with emphasis on ESS-related radionuclides. The existing modelling programmes were surveyed as well as the most relevant environmental parameters and experimental radioecological data required to build models specific to the ESS.In the second part of the report, the area in the vicinity of the ESS was surveyed to identify the important producers of foodstuff, what plant species are grown in the area and also the local husbandry and hunting practices, in order to identify critical pathways after a radioactive dispersion into the environment in connection with a potential accident at the ESS. In the third part of this report, after a thorough literature review and preliminary assays, we propose to investigate the use of ICP-MS for assessment of Gd-148 in the event of an accidental release, knowing that this analytical technique is already used for the measurement of stable Gd and REEs in the environment. The existing methods to extract REEs from environmental samples (soil, water, plants, and animal products) and to properly assess their concentration are described in the form of a literature review. The presented examples of methods were selected to fit the type of environment found around the ESS facility and the local agricultural and horticultural practices. A pilot study was also conducted to test extraction and measurement methods on the specific type of soil around ESS. These results are presented at the end of this report.
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