| 1. |
- Bengtsson, Stefan, et al.
(författare)
-
Importance of soil type on internal distribution of radiocaesium and radiostrontium in barley, oat and wheat.
- 2012
-
Ingår i: 13th International Congress of the International Radiation Protection Association (IRPA) in Glasgow, 13-18 May 2012.
-
Konferensbidrag (refereegranskat)abstract
- The release of radionuclides to the atmosphere can result in deposition of the radionuclides directly to terrestrial ecosystems. Following deposition, uptake from soil will also contribute to the activity that is internalized in plants and further transported in the terrestrial ecosystems. These two processes are of concern in the nutrition chains, cereals-bread-human and in feeding stuffs-cow-milk-human. The aim of this study was to quantify the internal distribution of (1) direct wet deposited 134Cs and 85Sr in wheat and (2) root uptake of 137Cs, from Chernobyl accident, in barley and oats, as well as the dependence of distribution on soil type. Wheat crop was grown at the Ultuna meteorological and agricultural field station (Uppsala County) and land management was in accordance with regional agricultural practice. The trial had a randomized block design with 1 × 1 m2 parcels with three replicates. 134Cs and 85Sr were deposited on wheat at three different growth stages by a rainfall simulator. Barley crops was grown at Helganbo (Uppsala County) and Möjsjövik (Uppsala County) and oat crops was grown at Björke (Gävle County), Hille (Gävle County) and Möjsjövik (Uppsala County) all places were in Sweden. Both crops were grown in accordance with regional agricultural practices. Sampling was made in the last growing stage from an area of 1 m2 and the different plant compartments (stem, head, husk and grain) for all crops were dried. Samples were placed in plastic jars and the activity was measured by High Purity Germanium (HPGe) detectors, calibrated for this sample geometry. The preliminary results indicate that the lowest distribution of 137Cs was found to the head and grains of barley and oat grown on loamy clay soil type. There is an indication that the distribution of 134Cs to the head and grains in wheat is not related to the time from the deposition of 134Cs to harvest. It was found to that the distribution of 134Cs to head was higher in the husks then to the grains. For 85Sr it was seen that at a deposition at harvest the highest amount was distributed to the husks compared to the grains. However, at a deposition at the growing stage “flowering” a higher amount was distributed to the head. Factors that influenced distribution of radionuclides were the soil type, type of radionuclide and time interval between deposition and harvest.
|
|
| 2. |
- Nilsson, Jenny, et al.
(författare)
-
The design of a low activity laboratory housing a whole body counter consisting of large plastic scintillators and the work towards a flexible Monte Carlo calibration
- 2014
-
Ingår i: Progress in Nuclear Science and Technology. - : The Atomic Energy Society of Japan. - 2185-4823. ; 4, s. 427-431
-
Tidskriftsartikel (refereegranskat)abstract
- After an accident or malicious act where the general public has been contaminated, or suspects contamination, of radioactive materials, the ability to perform accurate and fast measurements on large groups of people becomes crucial. The method used to assess internal contamination ought to be flexible in terms of source distribution and energy, as well as account for different body sizes. The method should also provide a possibility of follow-up studies. Whole body counting is a very suitable method for measurements on humans where contamination is suspected from ingestion of food products containing radioactive materials and/or from inhalation of radioactive particles or gas. At the University of Gothenburg two whole body counters, WBC, spectrometry systems are housed in a low activity laboratory. The laboratory building materials, the WBC shielding and the ventilation system are chosen and designed to obtain a low background. The laboratory and WBC systems were originally constructed in the late 60’s, but during the recent years the WBC systems have been updated and the laboratory and its surroundings renovated. The WBC System II consists of four large plastic scintillators, NE 102A, each measuring 91.5 × 76.0 × 25.4 cm3, where each detector is coupled to two 12″ photomultiplier tubes. The signal from each photomultiplier tube is added before it is recorded in a multichannel analyzer and the spectrum form each detector can then be added to one single spectrum. The large detectors provides a whole body counter with a nearly 3π geometry and thus a good efficiency, which makes the system well suited to perform the measurement tasks described above. An on-going work is to develop a Monte Carlo calibration of the system, using the codes MCNPX 2.6.0 and GATE 6.1.0, which gives the opportunity to easily change source geometry and energy calibration. We will present a description of the design and construction of the low activity laboratory and the updated System II together with measurement results. Also presented are examples of pitfalls and difficulties when designing a Monte Carlo calibration for large plastic scintillators, as well as the benefits with investigating the different steps in a plastic scintillator spectrometer system signal chain, which is not possible without the Monte Carlo method.
|
|
| 3. |
- Pálsson, S.E., et al.
(författare)
-
A simple model to estimate deposition based on a statistical reassessment of global fallout data
- 2013
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X. ; 121, s. 75-86
-
Tidskriftsartikel (refereegranskat)abstract
- Atmospheric testing of nuclear weapons began in 1945 and largely ceased in 1963. Monitoring of the resulting global fallout was carried out globally by the Environmental Measurements Laboratory and the UK Atomic Energy Research Establishment as well as at national level by some countries. A correlation was identified between fallout deposition and precipitation and an uneven distribution with latitude. In this study, the available data from 1954 to 1976 for 90Sr and 137Cs were reanalysed using analysis of covariance (ANCOVA) and logarithmically transformed values of the monthly deposition density as the response variable. Generalized additive models (GAM) were used to explore the relationship of different variables to the response variable and quantify the explanatory power that could be achieved. The explanatory variables which consistently explained most of the variability were precipitation at each site, latitude and change with time and a simple linear model was produced with similar explanatory power as the GAM. The estimates improved as the temporal resolution of the precipitation data increased. A good logelog fit could be obtained if a bias of about 1e6 mm precipitation per month was added, this could be interpreted as dry deposition which is not otherwise accounted for in the model. The deposition rate could then be explained as a simple non-linear power function of the precipitation rate (r0.2e0.6 depending on latitude band). A similar non-linear power function relationship has been the outcome of some studies linking wash-out and rain-out coefficients with rain intensity. Our results showed that the precipitation rate was an important parameter, not just the total amount. The simple model presented here allows the recreation of the deposition history at a site, allowing comparison with time series of activity concentrations for different environmental compartments, which is important for model validation.
|
|
| 4. |
- Piñero-García, Francisco, et al.
(författare)
-
Biodistribution of 210Po in seafood and risk assessment for consumers in Sweden
- 2023
-
Ingår i: Food Control. - 0956-7135. ; 151
-
Tidskriftsartikel (refereegranskat)abstract
- Seafood consumption per capita, in Sweden, is larger than World and European average. Although, 36% of Swedes consume seafood meals at least two times per week, the Swedish National Food Agency advises the necessity to increase this ratio. Seafood is one of the main entrances of 210Po in the human food chain. Due to the high radiotoxicity, the intake of 210Po plays an important role in the human health, even in extremely small quantities. In this study, 114 seafood samples representing 52 different marine species were analyzed. The biodistribution of 210Po in seafood species were not uniformly distributed being higher in digestive system and gonads, and lower in seafood muscle. The activity concentration of 210Po in fish ranged between 0.01 and 26 Bq/kg with an average value of 4 Bq/kg, whereas in shellfish fluctuated between 0.1 and 239 Bq/kg, with a mean concentration of 18 Bq/kg. In general, the activity concentration of 210Po in processed products were lower than fresh samples due to the decay of 210Po from seafood capture to purchase. However, in boiled seafood such as Norway Lobster, with short elapsed time from collection to purchase, the boil samples presented higher activity concentration of 210Po than fresh products. The results of the study showed that the annual intake of 210Po via seafood consumption in Sweden exponentially increased by age and it was slightly higher in males than females. As a result, the annual committed dose ranged from 60 to 154 μSv, with an average value of 103 ± 31 μSv, being controlled by fish consumption below 14 years old and by seafood consumption above 14 years old. Finally, the committed effective dose could increase up to 479 μSv/y for population group with higher seafood consumption.
|
|
| 5. |
- Piñero-García, Francisco, et al.
(författare)
-
Radiological impact of naturally occurring radionuclides in bottled water
- 2021
-
Ingår i: Food Control. - : Elsevier BV. - 0956-7135. ; 130
-
Tidskriftsartikel (refereegranskat)abstract
- Consumption of bottled water is increasing year after year in Europe. Due to the local geology from where the water is extracted; bottled water could be enhanced with radionuclides. This study focuses on the activity concentrations of 210Po, 210Pb, 226Ra, 228Ra, 234U and 238U in bottled water available in the Swedish market, to assess the radiological impact to different age groups. The results showed that among the 26 brands studied, only three could exceed the threshold value for drinking water: 0.1 mSv/year. For two brands, the dose was mainly due to the activity concentrations of 238U and 234U being up to 714 and 1162 mBq/L, respectively. While for one brand, the dose was mainly due to the activity concentration of both 210Po and 210Pb being around 100 mBq/L. For the remainder brands, 228Ra was the main contributor to the committed effective dose.
|
|
| 6. |
- Rääf, Christopher, et al.
(författare)
-
The first year of a Novel Swedish Master’s Degree Programme for Applied Radiation Protection
- 2014
-
Ingår i: The 4th European Regional IRPA Congress.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The education in medical radiation physics at university level in Sweden has a history from the early 1960s. Today, the programme consists of five years of studies. However, since the development in medical applications of radiation is so rapid there is little room in the schedule for giving the students a good training in radiation protection dealing with situations outside the medical sphere. It has been recognized by the Swedish Radiation Safety Authority, SSM, (among others) that there is a severe lack of experts in radiation protection concerning nuclear or radiological accidents and malicious use of radioactive sources. In accordance with this need for a new profession, here referred to as Applied radiation protection, the Medical Physics departments at Lund University (ass. prof. C. L. Rääf) and University of Gothenburg (prof. M. Isaksson) were commissioned by SSM in 2008 to elaborate an educational programme on a Master’s level. After some years of conceiving and launching new courses in radiation protection for national professional development (CPD) of medical physicists this Master programme started in fall 2012, with two courses at the Sahlgrenska Academy at the University of Gothenburg that were adapted from the CPD programme. “National emergency preparedness for radiation protection” focuses on the role of various authorities and stakeholders in the society. The course was given as a distance course with six mandatory meetings. During three days the students meet representatives from the authorities engaged in the emergency preparedness as lecturers. During these days, the course is run together with the medical physicists following the CPD-course of the same topic. “Radiation protection and environmental impact of the nuclear fuel cycle” was given later during fall 2012, also as a distance course, including three days combined with a CPD-course. Both courses on the master level were examined by calculation exercises and essays. During fall 2013 two more courses will be given: “Detectors and measurement methods in radiation protection and emergency preparedness” and “Radiation protection in medical emergency preparedness”, with the same structure as the courses above. Plans for the future involve making the courses in this Master programme in English, and thus open for international participants. There are also plans of running fragments of these courses together with the national specialist training of radiation protection staff within the nuclear industry, in order to provide them with lectures and seminars on an academic level as a part of their professional development. In return, such a collaboration would expand the Master programme into nuclear safety and reactor physics.
|
|
