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| 2. |
- Bengtsson, Stefan, et al.
(författare)
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Interception and retention of wet-deposited radiocaesium and radiostrontium on a ley mixture of grass and clover
- 2014
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 497-498, s. 412-419
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to assess the potential radioactive contamination of fodder in the case of accidental radionuclide fallout, and to analyse the relationship between interception and retention of radionuclides as a function of biomass and Leaf Area Index (LAI). The interception and the retention of wet deposited Cs-134 and Sr-85 in ley (a mixture of grass and clover) were measured after artificial wet deposition in a field trial in Uppsala (eastern central Sweden). The field trial had a randomised block design with three replicates. Cs-134 and Sr-85 were deposited at six different growth stages during two growing seasons (2010 and 2011) using a rainfall simulator. The biomass was sampled in the center of each parcel 2 to 3 h after deposition and at later growth stages (1 to 5) during the growing season. The above ground biomass and LAI were measured as well. The interception of radionuclides by the ley was largest at the late growth stages; the spike and tassel/flowering (code 5:6) in the 1st year, and at flowering/initial flowering (code 6:5) in the 2nd year. There was a correlation between radionuclide interception and above ground plant biomass, as well as with LAI, for both radionuclides in both years. The highest activity concentrations of both radionuclides were measured after deposition at the late growth stages and were found to be higher in the 2nd year. The weathering half-lives were shorter at the earlier growth stages than at the later growth stages for both radionuclides. For the magnitude of deposition chosen in our experiment, it can be concluded that the above ground biomass is a good predictor and the LAI a more uncertain predictor of the interception of radiocaesium and radiostrontium by ley grass and clover. (C) 2014 Elsevier B.V. All rights reserved.
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| 3. |
- Bengtsson, Stefan, et al.
(författare)
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Uptake and Retention of Simulated Fallout of Radiocaesium and Radiostrontium by Different Agriculture Crops
- 2015
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Ingår i: Radionuclides in the Environment. - Cham : Springer International Publishing. - 9783319221700 ; , s. 115-132
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Abstract: The contamination level in potato, oilseed rape and wheat in terms of tubers, seeds and foliage has been investigated after the foliar application of wet-deposited 134Cs and 85Sr at different growth stages in a microscale field experiment conducted over consecutive years. The results indicate that the application of radionuclides in the beginning of the growth season resulted in low 134Cs and 85Sr activity in both seeds of wheat, oilseed rape and potato tubers across sampling occasions. In the middle of the growth season during radionuclide fallout, 134Cs activity in potato tubers across sampling occasions was highest. The spraying of radionuclides at later stages resulted in even lower 134Cs activity in potato tubers but increased activity in seeds of wheat and oilseed rape.
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| 4. |
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| 5. |
- Rosén, Klas, et al.
(författare)
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137Cs in a raised bog in central Sweden
- 2009
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 100, s. 534-539
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Tidskriftsartikel (refereegranskat)abstract
- The vertical distribution of 137Cs activity in peat soil profiles and 137Cs activity concentration in plants of various species was studied in samples collected at two sites on a raised bog in central Sweden. One site (open bog) was in an area with no trees and only a few sparsely growing plant species, while the other (low pine) was less than 100 m from the open bog site and had slowly growing Scots pine, a field layer dominated by some ericaceous plants and ground well-covered by plants. The plant samples were collected in 2004–2007 and were compared with samples collected in 1989 from the same open bog and low pine sites. Ground deposition of 137Cs in 2005 was similar at both sites, 23 000 Bqm-2. In the open bog peat profile it seems to be an upward transport of caesium since a clear peak of 137Cs activity was found in the uppermost 1–4 cm of Sphagnum layers, whereas at the low pine site 137Cs was mainly found in deeper (10–12 cm) layers. The migration rate was 0.57 cmyr-1 at the open bog site and the migration centre of 137Cs was at a depth of 10.7, while the rate at the low pine site was 0.78 cmyr-1 and the migration centre was at 14.9 cm. Heather (Calluna vulgaris) was the plant species with the highest 137Cs activity concentrations at both sites, 43.5 k Bq-1 DM in 1989 decreasing to 20.4 in 2004–2007 on open bog and 22.3 k Bq kg-1 DM in 1989 decreasing to 11.2 k Bq-1 DM by the period 2004–2007 on the low pine site. 137Cs transfer factors in plants varied between 0.88 and 1.35 on the open bog and between 0.48 and 0.69 m2 kg-1 DM at the low pine site
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| 6. |
- Rosén, Klas, et al.
(författare)
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Accumulation of Cs-137 after potassium fertilization in plant organs of Salix viminalis L. and in combusted ash
- 2011
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 35, s. 2765-2772
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Tidskriftsartikel (refereegranskat)abstract
- The effect of potassium (K) application at a common rate on Cs-137 uptake and distribution within basket willow (Salix viminalis L.) and Cs-137 activity in willow ash was studied in a three-year field experiment on a sandy soil. Experimental plots fertilized with 60 kg N and 48 kg K per ha were compared with a control with similar N but no K fertilization. There was no significant difference in Cs-137 activity concentrations in plants growing on plots with or without fertilizer K. Higher concentrations of Cs-137 activity were found in roots and leaves of willow than in stems and cuttings. The highest Cs-137 activity concentration was detected in the fine roots (size 0-1 mm). The transfer factor (TFg) of Cs-137 in different plant organs varied between 0.1 x 10(-3) and 2.6 x 10(-3) m(2) kg (1). After combustion, Cs-137 activity concentrations in ash produced from wood chips from K-fertilized plots were significantly lower than those in ash originating from plots without K fertilization. Fly ash had higher Cs-137 concentrations than bottom ash and all ash samples had Cs-137 concentrations that were well below the 10 000 Bq kg(-1) Swedish limit for spreading on land. (C) 2011 Elsevier Ltd. All rights reserved.
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| 7. |
- Rosén, Klas, et al.
(författare)
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Interception and transfer of wet-deposited Cs-134 to potato foliage and tubers
- 2016
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 151, s. 224-232
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Tidskriftsartikel (refereegranskat)abstract
- Contamination levels on potato foliage and tubers were investigated by repeated sampling after multiple foliar contaminations of wet-deposited Cs-134 at five different growth stages in a micro-plot field experiment in three successive years. Application of the radionuclide early in the growing season (deposition date 19-27 June, growth stage II = plant establishment) resulted in low Cs-134 activity concentration in potato tubers across sampling occasions (mean 60, 25 and 115 Bq kg(-1) dry weight (D.W.) for years 1,2 and 3, respectively). Following radionuclide deposition in the middle of the growing season (15-24 July, growth stage III = tuber initiation), Cs-134 activity concentration in tubers across sampling occasions was found to be highest (mean 150, 850 and 660 Bq kg(-1) D.W. for years 1, 2 and 3, respectively). When the radionuclide was sprayed on at later stages (5-7 August, growth stage IV = tuber bulking), Cs-134 activity concentrations in tubers across sampling dates decreased (mean 75, 310 and 395 Bq kg(-1) D.W. for years 1, 2 and 3, respectively). Deposition in the second half of August (15-28 August, late growth stage IV and beginning of growth stage V = tuber maturation) resulted in yet lower Cs-134 activity concentration in tubers. Potato tubers may concentrate as much as up to 2 times more Cs-134 than foliage depending on deposition date of radionuclide. (C) 2015 Elsevier Ltd. All rights reserved.
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| 8. |
- Rosén, Klas, et al.
(författare)
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Long-term effects of single potassium fertilization on Cs-137 levels in plants and fungi in a boreal forest ecosystem
- 2011
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 102, s. 178-184
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Tidskriftsartikel (refereegranskat)abstract
- We examined the long-term effects of a single application of potassium (K) fertilizer (100 kg K ha(-1)) in 1992 on Cs-137 uptake in a forest ecosystem in central Sweden. Cs-137 activity concentrations were determined in three low-growing perennial shrubs, heather (Calluna vulgaris), lingonberry (Vaccinium vitis-idaea) and bilberry (Vaccinium myrtillus), and in four wild fungal species (Cortinarius semisanguineus, Lactarius rufus, Rozites caperata and Suillus variegatus). Uptake of Cs-137 by plants and fungi growing on K-fertilized plots 17 years after application of the K fertilizer was significantly lower than in corresponding species growing in a non-fertilized control area. The Cs-137 activity concentration was 21 -58% lower in fungal sporocarps and 40-61% lower in plants in the K-fertilized area compared with the control. Over the study period, this decrease in Cs-137 activity concentration was more consistent in plants than in fungi, although the effect was statistically significant and strongly pronounced in all species. The effect of K fertilization in reducing Cs-137 activity concentration in fungi and plants decreased over time but was still significant in 2009,17 years after fertilization. This suggests that application of K fertilizer to forests is an appropriate and effective long-term measure to decrease radiocaesium accumulation in plants and fungi. (C) 2010 Elsevier Ltd. All rights reserved.
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| 9. |
- Rosén, Klas, et al.
(författare)
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Potassium fertilization and Cs-137 transfer from soil to grass and barley in Sweden after the Chernobyl fallout
- 2014
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 130, s. 22-32
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Tidskriftsartikel (refereegranskat)abstract
- Fertilization of soils contaminated by radionuclides with potassium (K) and its effect on Cs-137 transfer from soil to crops is well studied in field conditions; however experiments over many years are few.The effects of potassium fertilization on cesium-137 (Cs-137) transfer to hay, pasture grass, and barley growing on organic rich soils and mineral sand and loam soils in a number of field experimental sites situated in different environments in Sweden are summarized and discussed. The basic experimental treatments were control (no K fertilizers were applied), 50, 100, and 200 kg K ha(-1). In the experiment, which lasted over 3-6 years, Cs-137 transfer factors in control treatments ranged between 0.0004 m(2) kg(-1) (barley grain on sand soil) and 0.07 m(2) kg(-1) (pasture grass on organic rich soil). Potassium application on soils with low clay content i.e. mineral sand and organic rich soils was effective at the 50-100 kg ha(-1) level. Application of 200 kg K ha(-1) resulted in a five-fold reduction in Cs-137 transfer for hay and up to four-fold for barley grain. The effects of potassium application were generally greater on sand than organic rich soil and were observed already in the first cut. After K application, the reduction in Cs-137 transfer to crops was correlated with Cs-137:K ratios in plant material. Additional application of zeolite caused a 1.4 reduction of Cs-137 transfer to hay on sand and 1.8-fold reduction on organic rich soil; whereas, application of potash-magnesia and CaO had no effect. (C) 2013 Elsevier Ltd. All rights reserved.
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| 10. |
- Rosén, Klas, et al.
(författare)
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Transfer of radionuclides and dose assessment to ants and anthills in a Swedish forest ecosystem
- 2018
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 190, s. 97-104
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Tidskriftsartikel (refereegranskat)abstract
- In forest ecosystems soil organisms are important for immobilization, translocation and recycling of radionuclides. Still, there is a lack of studies on the role of insects such as ants in the turnover of radionuclides and how radioactivity affects an ant community. In this study seven anthills were sampled in an area that was heavily contaminated after the fallout from the Chernobyl accident. Samples of ant and anthill materials were taken from different depths of the anthills as well as from the surrounding soil and the activity concentrations of Cs-137 were determined. In addition, a radiation dose assessment was performed for ants and anthills using the ERICA tool. The deposition of Cs-137 in 1986 in the study area was calculated back to be on average 110,500 Bq m(-2). The averaged data for all the seven locations investigated indicate that the level of Cs-137 activity concentrations in the anthill's material increased with depth of the anthill being highest at the depth 50-65 cm. The concentration in the upper layers (0-2 cm) and of the ants showed significant correlations with the deposition upon multivariate analysis.The concentration ratio (CR) defined as the ratio between the mass activity for Cs-137 density in ants (Bq kg(-1) d.w.) and mass activity density in soil (Bq kg(-1) d.w.) was determined to be in the range of 0.04-0.14.Also, the transfer factor (TF) defined as the ratio between the mass activity for Cs-137 density in ant (Bq kg(-1) d.w.) and to the unit area activity density (in Bq m(-2) d.w.) was determined for Cs-137 to be 0.0015 m(2) kg(-1) d.w. The assessed radiation doses were found to be a 4.9 mu Gy h(-1) which is below international reference levels for non-human biota.
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