共查询到20条相似文献,搜索用时 15 毫秒
1.
J. W. Mietelski B. Kubica P. Gaca E. Tomankiewicz S. Błażej M. Tuteja-Krysa M. Stobiński 《Journal of Radioanalytical and Nuclear Chemistry》2008,275(3):523-533
Activity concentrations and inventory for 238Pu, 239+240Pu, 241Am, 90Sr, and 137Cs in soil from Tatra Mountains of Poland are presented. Soil samples were collected using 10 cm diameter cores down to 10
cm and sliced into 3 slices. Details of the applied procedure are described with the quality assurance program. The maximum
activity concentrations found for various samples were: 1782±13 Bq/kg, 17.4±0.9 Bq/kg, 3.4±0.3 Bq/kg and 84±7 Bq/kg for 137Cs, 239+240Pu, 241Am and 90Sr, respectively. The maximum cumulated deposition of 239+240Pu is 201±8 Bq/m2. The origin of radionuclides is discussed, based mostly on the observed isotopic ratio of Pu. Significant correlations were
found between 239+240Pu, 241Am and 137Cs. The effective vertical migration rate seems to be in the order of: 90Sr≫Pu>Am>Cs. 相似文献
2.
L. Sha M. Yamamoto K. Komura K. Ueno 《Journal of Radioanalytical and Nuclear Chemistry》1991,155(1):45-53
This paper gives the first data on239,240Pu and241Am in Chinese soils. Surface soil samples with a set of 0–5 cm and 5–20 cm depth were collected from Beijing, Taiyuan, Shijiazhuang and Jinang of China in 1990, and239,240Pu,241Am and137Cs, including naturally occurring radionuclides, in these samples were measured to evaluate their present levels and distributions. From these results, the average accumulated depositions were estimated roughly to be 24±13 MBq/km2 for239,240Pu, 10±5 MBq/km2 for241Am and 1.2±0.7 GBq/km2 for137Cs. The activity ratios of239,240Pu/137Cs and241Am/239,240Pu ranged from 0.016 to 0.026 with a mean value of 0.020±0.004 and 0.35 to 0.49 with a mean value of 0.43±0.05, respectively. 相似文献
3.
D. Desideri S. Giuliani C. Testa C. Triulzi 《Journal of Radioanalytical and Nuclear Chemistry》2003,258(2):221-225
During the last 14 years the Radioecology Laboratory of Parma University and the General Chemistry Institute of Urbino University collaborated on a radioecological programme having the aim to observe the evolution of antropogenic radioactivity in Antarctica in the period 1987-2001. The artificial radionuclides considered were 90Sr, 137Cs, 239+240Pu,238Pu and 241Am. The contamination seems to be higher in the continental environment rather than in the marine one. Mosses, algae and lichens showed the highest values for all radionuclides analyzed. The results prove that the Antarctic continent is interested by radioactive pollution. As far as 137Cs is concerned, a progressive decrease was observed. 相似文献
4.
J. W. Mietelski J. LaRosa A. Ghods 《Journal of Radioanalytical and Nuclear Chemistry》1993,170(1):243-258
Strontium-90, plutonium and americium activity concentrations in a few samples of forest soils, some species of mushrooms and fern leaves have been determined. These results are compared with cesium activity concentrations in the same materials obtained in a previous work. Radiochemical procedures are described. The origin of the contamination (Chernobyl accident or nuclear test explosion release) is discussed. The90Sr activity concentration ranges from 0.6 Bq/kg (mushroom samples) to 48.4 Bq/kg (fern leaves). For239+240Pu, it ranges from not detected above background (mushrooms, fern) to 10.8 Bq/kg (humus layer of forest soil). The maximum concentration of241Am is found to be 2.4 Bq/kg (humus sample) and for238Pu it is 0.85 Bq/kg (also in the humus sample). 相似文献
5.
R. C. L. Figueira E. S. B. G. Saraiva I. I. L. Cunha 《Journal of Radioanalytical and Nuclear Chemistry》2001,248(3):801-804
Methodologies for simultaneous analysis of 137Cs, 90Sr, 238Pu and 239+240Pu were developed and applied to seawater samples. 137Cs levels in Brazilian coastal seawater ranged from 0.12 to 4.7 Bq·m-3, for 90Sr from 2.0 to 8.6 Bq·m-3, for 239+240Pu from 0.8 to 4.5 mBq·m-3 and for 238Pu it was of 1.9 mBq·m-3. The artificial radioactivity levels in Brazilian seawater are typical values due to fallout deposition. 相似文献
6.
P. I. Mitchell W. R. Schell A. McGarry T. P. Ryan J. A. Sanchez-Cabeza A. Vidal-Quadras 《Journal of Radioanalytical and Nuclear Chemistry》1992,156(2):361-387
Six peat cores taken from three unmodified blanket and raised bogs in Ireland were sectioned and analyzed for a range of radionuclides including134Cs,137Cs,238Pu,239Pu,241Am, and210Pb.134Cs and137Cs were measured by high resolution gamma-spectrometry, while the transuranium nuclides were determined after chemical separation by alpha-spectrometry.241Pu, present on the electroplated discs together with Pu(), was measured directly by low-level liquid scintillation counting. Core chronologies were established by measuring the unsupported210Pb component using low energy photon spectrometry (LEPS). From the resulting profiles, relaxation depths and migration rates for the above mentioned radionuclides have been determined and differences in the values of these parameters interpreted.238Pu/239,240Pu and241Pu/239,240Pu ratios have been examined carefully and are discussed in some detail. Finally, the contribution from Chernobyl to the total radiocaesium inventory in each core has been established using the134Cs/137Cs ratio observed in the initial fallout from Chernobyl. 相似文献
7.
The cumulative depositions of137Cs,90Sr and fallout Pu in the volcanic ash soil of Korea were determined. The average accumulated depositions of137Cs,90Sr and fallout Pu in the volcanic soil were much higher than those in other forest sites of Korea. From depth profiles, it
was found that137Cs,90Sr and239,240Pu in the volcanic soil are more mobile than those in other forest sites of Korea, and that the downward movement of90Sr is faster than137Cs and239,240Pu. A significant correlation was found between the concentration of137Cs and those of90Sr and239,240Pu. The activity ratios of238Pu/239,240Pu and241Pu/239,240Pu in soils are close to those observed in the cumulative deposit from the global fallout of nuclear weapon testings. 相似文献
8.
J. Moreno N. Vajda P. R. Danesi J. J. Larosa E. Zeiller M. Sinojmeri 《Journal of Radioanalytical and Nuclear Chemistry》1997,226(1-2):279-284
A combined procedure for sequential determination of low level activity concentrations of90Sr,241Am and Pu radionuclides is described. The analysis of -emitters is performed by isotope dilution -spectrometry using242Pu or236Pu and243Am tracers. Strontium-90 is analyzed by liquid scintillation counting using the double energetic windows method. The method combines the well established, procedure for Pu analysis based on anion exchange, the powerful and selective method for Sr isolation based on extraction chromatography using Sr-Spec resin and finally it includes the application of the TRU-Spec column for separation and purification of the Am fraction. The radiochemical procedure was tested using IAEA reference and intercomparison materials. Major parameters of the procedure as well as advantages and drawbacks are discussed in detail. 相似文献
9.
Bio-availability of radionuclides in soil is influenced by their chemical form and association with different geo-chemical phases. The solid phase speciation of aged90Sr,137Cs,239Pu and241Am in three common agricultural soil types was investigated using separate extractions with seven reagents. Six of these are commonly used to determine radionuclide association with readily exchangeable forms, carbonates, iron and manganese oxides and organic phases. Trimethyl-chlorosilane was also included because of its ability to extract radionuclide-humate complexes from soil. The extract from this part of the study was subsequently subjected to ultra-filtration to determine the association of radionuclides with different molecular size fractions. The results from this speciation study are discussed in terms of availability for plant uptake. 相似文献
10.
N. Hayashi J. Ishida A. Yamato M. Iwai M. Kinoshita 《Journal of Radioanalytical and Nuclear Chemistry》1987,115(2):369-376
An accurate and reliable method has been developed and routinely carried out for the sequential determination of239,240Pu and241Am in environmental samples. After suitable pretreatment.239,240Pu and241Am are separated from other elements by means of the anion exchange resin method. Americium-241 is purified by coprecipitation with calcium oxalate and then ion exchanged in mixed media of the mineral acid-methanol. In the analysis,242Pu (or236Pu) and244Cm are used as chemical yield monitors. The recoveries of the yield monitors in the analyses of some kinds of environmental samples were 7080% for plutonium and 7686% for curium. The concentration of239,240Pu in the coastal sea water were 7.022 Bq/l and that of241Am was 1.26.3 Bq/l. The mean concentrations of239,240Pu in the edible parts of the marine products ranged from 0.22 to 7.4 mBq/kg · fresh and those of241Am ranged from 0.11 to 2.6 mBq/kg · fresh. 相似文献
11.
Nevenka M. Antovic Perko Vukotic Nikola Svrkota Sergey K. Andrukhovich 《Journal of Radioanalytical and Nuclear Chemistry》2012,293(1):299-302
Plutonium-238 (238Pu) activity concentrations in soil samples from Montenegro (six samples from three localities) have been measured for the first time. The 238Pu/137Cs activity ratio was determined on the basis of alpha and gamma-spectrometric measurements, and found to be with an average of 0.0006 and standard deviation of 0.0003. By using the activity ratios determined in the present study, 238Pu activity concentrations were estimated for three localities in the central: one in the northern, and two in the eastern part of Montenegro. 相似文献
12.
Host phases of fallout239,240Pu and241Am were studied in the surface sediments obtained in 1994 from abyssal basins of relatively small area of the western North
Pacific. An analytical procedure involving sequential chemical extraction was employed for partitioning the host phases of
the nuclides in sediment into five fractions: (1) exchangeable (2) bound to carbonate, (3) bound to hydrous Fe-Mn oxides,
(4) bound to organic matter and (5) residual. Decrease of total239,240Pu concentration with decreasing association of239,240Pu with organic matter, high241Am/239,240Pu activity ratio in carbonate phase and somewhat high proportion of oxidized239,240Pu in leachable phases suggest a possibility of post-depositional diagenetic remobilization of Pu from sediment to water column. 相似文献
13.
D. Desideri S. Giuliani M. A. Meli C. Testa C. Triulzi M. Vaghi 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(1):9-12
During the last ten years, the Italian Universities of Parma and Urbino collaborated on a special radioecological program
having the aim to study the levels and the distribution of long-lived radionuclides in different marine and terrestrial matrixes.
This paper summarizes the results concerning the concentrations of 239+240Pu and 238Pu, 241Am and 137Cs in sediments collected in the Ligurian and South Tyrrhenian Seas (Rapallo Harbour, Vado Ligure Canyon, Eolie Islands).
Superficial sediments and sediment cores were collected. For cores the vertical distribution was calculated and the sedimentation
rate obtained. 137Cs was determined directly by gamma-spectrometry, while 239+240Pu, 238Pu and 241Am were separated by extraction chromatography, electroplating and determined by alpha-spectrometry.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
D. Mascanzoni 《Journal of Radioanalytical and Nuclear Chemistry》1992,161(2):483-488
After the Chernobyl accident high concentrations of radionuclides were found in Sweden in mushrooms and the contents of90Sr and137Cs were measured. The level of90Sr was generally low and, in proportion to137Cs, 2–3 orders of magnitude lower than in the fallut. The contents of137Cs varied among species and extreme local variations occurred. The ratio134Cs/137Cs diverged from other biological samples leading to the conclusion that old fallout was involved in the uptake. 相似文献
15.
R. F. Payne S. B. Clark J. T. Elliston 《Journal of Radioanalytical and Nuclear Chemistry》2008,277(1):269-274
The simultaneous determination of multiple actinide isotopes in samples where total quantity is limited can sometimes present
a unique challenge for radioanalytical chemists. In this study, re-determination of 238Pu, 239+240Pu, and 241Am for soils collected and analyzed approximately three decades ago was the goal, along with direct determination of 241Pu. The soils had been collected in the early 1970’s from a shallow land burial site for radioactive wastes called the Subsurface
Disposal Area (SDA) at the Idaho National Lab (INL), analyzed for 238Pu, 239+240Pu, and 241Am, and any remaining soils after analysis had been archived and stored. We designed an approach to reanalyze the 238Pu, 239+240Pu, and 241Am and determine for the first time 241Pu using a combination of traditional and new radioanalytical methodologies. The methods used are described, along with estimates
of the limits of detection for gamma-and alpha-spectrometry, and liquid scintillation counting. Comparison of our results
to the earlier work documents the ingrowth of 241Am from 241Pu, and demonstrates that the total amount of 241Am activity in these soil samples is greater than would be expected due to ingrowth from 241Pu decay. 相似文献
16.
A radiochemical procedure is described for the simultaneous determination of238Pu,239+240Pu,241Pu,241Am,242Cm,244Cm,89Sr, and90Sr in vegetation samples. The method was applied for the determination of these, radionuclides in grass, collected near Munich after the fallout from the reactor accident at Chernobyl, USSR. The specific activities observed were (in Bq kg–1 dry weight):238Pu, 0.077;239+240Pu, 0.15;241Pu, 3.9;241Am, 0.031;242Cm, 3.0;244Cm, 0.008;89Sr, 2000;90Sr, 99. 相似文献
17.
Energy straggling in pulse height distributions of plastic scintillation counters of 4 and 10 cm in thickness was measured for 1 GeV/c pions and studied by Monte Carlo simulations. Calculated energy loss distributions are in good agreement with the experimental data and also with the prediction by the Landau straggling function. 相似文献
18.
B. Lukšienė E. Maceika N. Tarasiuk E. Koviazina V. Filistovič Š. Buivydas A. Puzas 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(1):277-286
Distributions of 239,240Pu, 238Pu and 137Cs activity concentrations in the cores of sediments in the shallow lake, flooded and upland forest soils taken in the vicinity of Vilnius city were analyzed. The radiochemical, α-spectrometric and mass spectrometric methods were used for the plutonium evaluation and γ-spectrometry was used for the radiocesium evaluation. The only peak of enhanced radionuclide activity concentrations was determined for the lake bottom sediments, whereas vertical profiles of the radionuclide activity concentrations in flooded and upland forest soil cores were distinguished by two peaks. The obtained values of the activity concentration ratio 238Pu/239,240Pu and the isotopic ratio 240Pu/239Pu indicated that the global fallout was a source of plutonium in the investigated environment. Chernobyl-derived radiocesium was detected solely in the surface layers (2–11 cm) of the studied sample cores. The contribution of the Chernobyl deposits amounted to about 2.26, 6.11 and 20.9 % of the total radiocesium inventory in the bottom sediments, the upland soil and flooded soil, respectively. 相似文献
19.
Rzemek Katarzyna Czerwiński Andrzej Ośko Jakub Tymińska Katarzyna Dymecka Małgorzata Pliszczyński Tomasz 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(2):1271-1276
The aim of this work is to present the method for sequential plutonium and americium activity determination in air filters using chromatographic radionuclide separation and alpha spectrometry measurement. The developed method may be employed for the purposes of workplace monitoring and as an indicator of the need of introducing the individual monitoring as well as a useful complementation of individual monitoring. Basic parameters describing the developed method such as values of chemical recoveries and minimum detectable activities for plutonium and americium isotopes have been determined. Applied counting efficiency was obtained using Monte Carlo calculation method.
相似文献20.
M. H. Lee C. W. Lee K. H. Hong Y. H. Choi B. H. Boo 《Journal of Radioanalytical and Nuclear Chemistry》1996,204(1):135-144
Depth distribution of239,240Pu and137Cs in the soils of South Korea have been studied. The average accumulated depositions were estimated roughly to be 54.8±32.1 Bq·m–2 for239,240Pu, 1.6±1.0 Bq· ·m–2 for238Pu and 1982.8±929.1 Bq·m–2 for137Cs. The activity ratios of239,240Pu/137Cs in soils were found to be in the narrow range of 0.0153 to 0.0364 with a mean value of 0.0230±0.006. The concentrations of239,240Pu and137Cs in soils decrease exponentially with increasing the soil depth. A significant correlation was found between the concentration of239,240Pu and that of137Cs. The activity ratios of239,240Pu/137Cs tend to increase slightly with increasing soil depth. 相似文献