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1.
P. Jurček V. Jedináková-Křížová P. Ivanová 《Journal of Radioanalytical and Nuclear Chemistry》1996,208(2):519-527
Retardation mechanisms of134Cs and85Sr have been investigated. Batch determination of distribution coefficientK
d
have been carried out for various values of factors affecting retardation such as solid-liquid ratio, particle size, composition of solid phase. Various types of bentonites and mixtures of bentonites with sand have been also studied. 相似文献
2.
A. C. Andrello C. R. Appoloni E. A. Cassol F. L. Melquiades 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(3):761-765
Summary Cesium-137 methodology has been successfully used to assess soil erosion. Seven erosion plots were sampled to determine the
137Cs profile and to assess the erosion rates. Cesium-137 profile for native pasture plot showed an exponential decline below
5 cm depth, with little 137Cs activity in the superficial layer (0-5 cm). Cesium-137 profile for wheat-soybean rotation plot in conventional tillage
showed a uniform distribution with depth. For this plot, the soil loss occurs more in middle than upper and lower level. Cesium-137
profile for wheat-soybean rotation and wheat-maize rotation plots in no-tillage showed a similar result to the native pasture,
with a minimum soil loss in the superficial layer. Cesium-137 profile for bare soil and cultivated pasture plots are similar,
with a soil erosion rate of 229 t ha-1 year -1 . In the plots with a conventional tillage a greater soil loss occur in middle than upper and lower level. In no-tillage
cultivation plots occurs soil loss in lower level, but no sign of soil loss neither gain in the upper level is observed. Cesium-137
methodology is a good tool to assess soil erosion and the 137Cs profile gives possibility to understand the soil erosion behavior in erosion plots. 相似文献
3.
Distribution coefficients Kd for the sorption of Cs and Sr on mixtures of a clay mineral (Ca-saturated bentonite) and humic material (Ca-humate) have been measured and were compared with calculated values obtained from the Kd-values observed for the pure components. The concentration of Sr and Cs in the solution was varied between 1·10–6 and 0.01N and the distribution of the elements determined by using radioactive tracers. All experiments were carried out in pure water as well as in the presence of a supporting electrolyte (0.01N CaCl2). It was found that the differences between the observed and calculated Kd-values were, if present, always negative if Cs was sorbed, and positive if Sr was sorbed. 相似文献
4.
The vertical migration of 85Sr, 137Cs and 131I in some arable and undisturbed single-contaminated soils was studied by gamma-spectrometry measurements under lysimetric laboratory conditions during irrigation of the soil profiles with wet atmospheric precipitation for about one year, except 131I. A new simple exponential compartment (box) model was derived, which makes it possible to calculate the migration rate constants and migration rates in the individual soil layers (vertical sections) as well as the total vertical migration rate constants and total vertical migration rates of radionuclides in the bulk soil horizon. The relaxation times of radionuclides in respective soil horizons can also be evaluated. 相似文献
5.
M. M. El-Dessouky A. N. Sharaf El-Deen 《Journal of Radioanalytical and Nuclear Chemistry》1988,125(2):481-484
Separation of Cs, Sr and Ca from their mixture was studied using solvent extraction and ion exchange techniques. More than 90% separation efficiency was achieved for Ca–Sr separation using ion exchange resin (Doulite C-20) while solvent extraction amounted to 88%. A proposed technique for determination of137Cs and89Sr in milk (after removal of organic matter) showed more than 80% accuracy for89Sr determination and more than 90% for137Cs determination. 相似文献
6.
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
7.
8.
Investigation of adsorption and vertical migration of137Cs in three kinds of soil at Lublin vicinity
S. Chibowski J. Zygmunt Z. Klimowicz 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(2):287-295
The results of field, column and laboratory studies carried out on three types of mineral soils are encloses presented. Based
on the field tests, average migration rates of137Cs were calculated. The highest rate was found for the brown soil (FAO/UNESCO—Cambisol). Cesium migrated with the lowest rate
in the podzol soil (FAO/UNESCO—Cambic Podzol). The column experiments confirmed the above observation. In laboratory tests
the adsorption and desorption isotherms of Cs were determined on samples taken from 0–2 cm layers of each soil profile. It
was found from the calculated partition coefficients that Cs is always irreversibly bonded to some extent, but it appears
to be completely and irreversibly immobilized on the podzol soil. The permanent retention of cesium in the podzol soil was
also confirmed by microcalorimetric studies. The desorption energy was negligibly small and amounted to −0.21 mJ/g. In the
brown soil, containing prevailing amounts of loamy minerals, the desorption energy was found to be 106.89 mJ/g. The investigations
are supplemented by the sorption kinetics measurements. These indicate that the adsorption equilibrium is reached after a
dozen, up to twenty or so minutes. 相似文献
9.
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
10.
P. Jurček V. Jedináková-Křižová 《Journal of Radioanalytical and Nuclear Chemistry》1998,229(1-2):57-60
Sorption and diffusion processes with134Cs and85Sr in natural bentonites have been investigated. The distribution coefficients (K
d
) have been determined by a batch method. Various factors affecting theK
d
value as water-to-bentonite ratio, concentration of the competitive cations in the aqueous phase or bentonite-to-sand ratio
in the mixed sorbents have been evaluated. A comparison of the sorption and diffusion data has been made. 相似文献
11.
M. S. Al-Masri A. Nashawati Y. Amin B. Al-Akel 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):289-295
Summary Transfer
of 226Ra, 85Sr and 137Cs from cow and sheep
milk to various Syrian dairy products has been evaluated. Dairy products
include Kashkivan cheese, braided cheese, Haloom cheese, Sircassian cheese,
liquid cheese, native cheese, cottage, thick yogurt, butter and milk cream. The
results showed that the percentage of 226Ra, 85Sr and 137Cs
transferred from cow milk to milk cream (Pt=food
processing retention factor′processing efficiency′100%) has reached 32%, 16% and 7%,
respectively. Butter and liquid cheese were found to have the lowest percentage
of transferred 226Ra, 85Sr and 137Cs.
Most of the obtained Pt values of the studied radionuclides
in thick yogurt were relatively low in spite of the high processing
efficiencies of thick yogurt. Moreover, the transfer, Pt, of
the studied radionuclides from cow milk to the prepared cheese was higher than
those values determined for sheep milk. This is due to differences in chemical
compositions of each type of milk. On the other hand, the treatment of Native
cheese, most commonly consumed cheese in Syria, with different concentrations
of NaCl solutions showed that 137Cs was completely removed from
cheese soaking in 5% NaCl solution (soaking time of 48 hours), while 40% of 226Ra
and 80% of 85Sr were also decontaminated using 0-2.5% NaCl solutions
and soaking time of 48 hours. Based on the obtained results, industrialization
processes of the dairy products that resulted the removal of radionuclides have
been identified.</p>
</p> 相似文献
12.
Due to the mismanagement of nuclear waste as well as heat exchanger degradation for the primary coolant of the one megawatt nuclear research reactor, the fission product137Cs has been leaking to the environment ever since 1969. In the past thirty years, the long-lived137Cs was accumulated and eventually trapped in the mud of the discharge pond right in front of the waste storage and the reactor facility. The distribution of137Cs in mud was measured and contour-mapped to reveal the migration of trace levels of137Cs in a period of three decades. 相似文献
13.
M. V. R. Prasad D. S. Surya Narayana R. K. Jeevanram 《Journal of Radioanalytical and Nuclear Chemistry》1995,197(2):281-293
A sequential method has been developed for the estimation of106Ru,137Cs, and90Sr in urine using beta counting. After completely destroying the organic matter in urine,106Ru is oxidized to volatile ruthenium tetroxide and allowed to reactin-situ with polyethylene powder;137Cs is concentrated on ammonium phosphomolybdate and estimated as tetraphenylborate;90Sr is coprecipitated as strontium sulphate and converted to carbonate. The recoveries have been found to be better than 83% for all of the radionuclides. The minimum detection limits are 0.16, 0.85, and 0.14 Bq/dm3 for106Ru,137Cs, and90Sr, respectively. Yttrium-90 fraction of90Sr is also estimated using sodium nitroprusside as reagent, after allowing it to grow for 14 days.This work forms part of the doctoral work of SRIM.V.R. PRASAD to be submitted to the University of Madras, under the supervision of DR. O.M. SREEDHARAN. 相似文献
14.
G. Lujaniene A. Plukis E. Kimtys V. Remeikis D. Jankünaite B.I. Ogorodnikov 《Journal of Radioanalytical and Nuclear Chemistry》2002,251(1):59-68
The vertical distribution of 137Cs, 90Sr, 239,240Pu, 238Pu and 241Am was determined in soil samples collected from the Chernobyl exclusion zone in 1994. The results show very close distribution profiles for all radionuclides, with about 90% of the total activity of each nuclide lying between the surface and the fourth centimeter. Sequential extraction methods were used to determine the association of radionuclides in soil. The data on vertical distribution of radionuclide species were used to calculate their vertical migration parameters. 相似文献
15.
Teramage Mengistu T. Sun Xinchao 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(1):233-244
Journal of Radioanalytical and Nuclear Chemistry - The ambient dose rate (ADR) in a coniferous forest floor contaminated by Fukushima-derived 137Cs was calculated for small temporal scale as a... 相似文献
16.
Zhiyuan Chang Lijun Diao Songsheng Jiang Anli Li Min Zhao 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(1):61-68
Vezetéknév
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
17.
Chunli Liu Xiangyun Wang Shushen Li Zhiming Wang Jinsheng Wang Bing Li Ling Jiang 《Journal of Radioanalytical and Nuclear Chemistry》2001,247(2):429-434
As part of a co-operative research project between the China Institute for Radiation Protection (CIRP) and the Japan Atomic Energy Research Institute (JAERI) on safety assessment method for shallow land disposal of low level radioactive wastes, the migration of 85Sr in unsaturated Chinese loess under natural and artificial rainfall conditions was in-situ investigated. 3H was used for obtaining the migration velocity of the moisture water in the test zone. The result of the 2-year test indicated that under natural rainfall conditions, the migration of 85Sr is a combination of downward and upward movements. It moves down in summer and moves up in winter. Under artificial rainfall conditions the migration of 85Sr is a velocity-change process. It migrates down faster in summer and slower in winter. This phenomenon is considered to be caused by the dry winter and relatively wet summer. 相似文献
18.
To ascertain the feasibility of using 137Cs and 210Pb in soil erosion models a Compton suppression system with a Be window was used to simultaneous detect both of the naturally occurring isotopes. In particular, the system allowed the use of only 20 g of soil material instead of the usual needed 0.5-1.0 kg in similar soil studies. 相似文献
19.
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