共查询到20条相似文献,搜索用时 62 毫秒
1.
A. A. ?u?ulovi? D. Veselinovi? S. S. Miljani? 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(9):1547-1549
Desoprtion of 137Cs from samples of Cetraria islandica lichen using HCl (A) and HNO3 (B) acid solutions with pH values from 2.00 to 3.75 was investigated. After five consecutive desorptions lasting 24 h it was
shown that between 52.2% (solution B pH 3.28) and 72.2% (solution A pH 2.00) of 137Cs was desorbed from the lichen and the initial desorptions were the most successful. Lichen desorbed with the stated solutions
did not undergo structural changes. The amount of absorbed water from solutions A and B, used for desorption from lichen, in relation to the starting volume (expressed in %) showed that solution concentration
did not take place. Lichen act as neutralizing agents because the pH of the lichen thallus is higher than the pH value of
the solution used
The article is published in the original. 相似文献
2.
Lichens, sampled around Chernobyl in 1990 and in Slovenia in 1992, were analyzed for radionuclides and elements, including Cs. Data were processed by Monte Carlo aided Target Transformation Factor (MCTTFA). The resulting factors indicate environmental accumulation routes. 40K : K and 210Pb : Pb ratios tested the procedure, showing fully mixed 40K and K, while for 210Pb and Pb the expected variability in specific radioactivity was confirmed. 137Cs showed a large factor-specific variability in 137Cs : Cs ratios. For the 1990 data, MCTTFA singled-out 137Cs in a separate factor, suggesting that the overall behavior of 137Cs cannot be derived from that of Cs: source (route)-related specific radioactivity makes that all individual transport-components should be taken into account. 相似文献
3.
For source identification, measurement of 135Cs/137Cs atomic ratio not only provides information apart from the detection of 134Cs and 137Cs, but it can also overcome the application limit that measurement of the 134Cs/137Cs ratio has due to the short half-life of 134Cs (2.06 y). With the recent advancement of ICP-MS, it is necessary to improve the corresponding separation method for rapid and precise 135Cs/137Cs atomic ratio analysis. A novel separation and purification technique was developed for the new generation of triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-MS/MS). The simple chemical separation, incorporating ammonium molybdophosphate selective adsorption of Cs and subsequent single cation-exchange chromatography, removes the majority of isobaric and polyatomic interference elements. Subsequently, the ICP-MS/MS removes residual interference elements and eliminates the peak tailing effect of stable 133Cs, at m/z 134, 135, and 137. The developed analytical method was successfully applied to measure 135Cs/137Cs atomic ratios and 135Cs activities in environmental samples (soil and sediment) for radiocesium source identification. 相似文献
4.
R. M. Anjos M. Rizzotto N. Sanches H. Velasco D. L. Valladares K. D. Macario 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(1):7-10
Distribution of 40K and 137Cs in tissues of the Citrus aurantifolia was measured by gamma spectrometry. A simple theoretical model is also proposed to describe the temporal evolution of 40K activity concentration in such tropical woody fruit species. This model exhibits close agreement with the 40K experimental results, in the leaf growing and fruit ripening processes of lemon trees. 相似文献
5.
Chih-Yu Chiu Shu-Yin Lai Chih-Jung Wang Yu-Ming Lin 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(3):511-515
The distribution of137Cs in an undisturbed, multistoried, subtropical wet montane forest ecosystem surrounding Yuanyang Lake (lake surface level
ca. 1670m, in northeastern Taiwan), was investigated. The mossy forest here represents a currently-rare perhumid temperate
environment in subtropical region. The radioactivity concentration of137Cs was determined by γ-spectroscopy with a Ge(Li) detector. Although the soil is extremely acidic (pH 3.3 to 3.6) and the
rainfall is high,137Cs is evidently retained in the organic layer. The radioactivity concentration of137Cs in surface soil ranges from 28 to 71 Bq·kg−1. The concentrations of137Cs in the ground moss layer and litter were much lower than that in the soil organic layer, this suggests that137Cs detected is not from the newly deposited radioactive fallout. The radioactivity concentration and transfer factor (TF)
of137Cs varied with plant species. Shrubs and ferns have higher values than a coniferous tree (Taiwan cedar). The TF in this ecosystem
is as high as 0.21 to 1.88. The high values of TF is attributed to the abundance of the organic matter in the forest soils.
The rapid recycling of137Cs through the soil-plant system of this undisturbed multistoried ecosystem suggests the existence of an internal cycling
that help the accumulation of137Cs in this ecosystem. 相似文献
6.
Contamination of ground level air at Lublin town was studied by measurements of radioactive isotope and heavy metal contents in Parmeliaceae lichens exposed during six months on the area of the town. The concentration of the elements studied was compared with these ones measured in unexposed (blank) samples of lichens. The highest increase of radioactivity was noticed for 232Th, 226Ra and 40K. The contamination by 137Cs does not increased markedly, ranging from 2 to 107 Bq/kg of the dry lichen sample. Nearly half of the exposed samples do not reveal any increase of cesium radioactivity. Heavy metal concentrations in analyzed lichens were low. From the results obtained, one may conclude that concentration of these metals in ground air level does not reach appreciable values. 相似文献
7.
Barbara Kubica Katarzyna Szarlowicz Marcin Stobinski Stefan Skiba Witold Reczynski Janusz Gołas 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(3):1313-1320
The aim of the study is to present the results of determination of radioactivity of artificial 137Cs and natural 40K and certain heavy metals in soil samples collected from the eastern part of the Main Ridge of Carpathians, including the Beskid Niski Mts and the Bieszczady Mts. The evaluation of level of radionuclides was based on the bulk density analysis of the soil. A valuable finding of the study was a good linear correlation between the level of 137Cs concentration and bulk density of the soil as well as an inverse correlation between radioactivity of natural 40K and tested soil density. This might indicate though a high competitiveness of these elements between each other. Moreover, a good correlation between the concentrations of artificial element 137Cs and Pb has been also observed in soil samples collected from the Beskid Niski Mts. In most cases, the level of artificial 137Cs was lower comparing to an average 137Cs concentration established for soils in Poland. 相似文献
8.
D. Mascanzoni 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(2):427-431
The radioactive contamination following the Chernobyl accident resulted in high concentrations of 137Cs in several mushrooms species. Mushroom samples were collected in a forest environment between 1986 and 2007 and the transfer
of 137Cs to two edible species, Suillus variegatus and Cantharellus spp., was investigated. The 137Cs uptake by the collected samples did not decrease over time and in Cantharellus spp. a significant increase was observed. Most of the 137Cs in soil still appears to be available for uptake and radioactive decay of the radionuclide is likely the main factor for
the reduction of 137Cs in a forest ecosystem. 相似文献
9.
S. Chibowski J. Solecki J. Bystrek 《Journal of Radioanalytical and Nuclear Chemistry》1998,230(1-2):319-322
The results of investigations of the level of contamination by γ-radioactive isotopes of lichens fromParmeliaceae family, collected in the years 1949–1996 are presented. The most important isotope, occurring in significant amount was137Cs. From the natural isotope group also40K,226Ra,210Pb,234Th and214Bi were found in few samples. Starting from 1956, the137Cs isotope is detected in all collected samples with two distinct maxima in 1963 and 1989. Taking into accunt the age of the
collected lichens, their activity and the level of the radioactivity fall-out, the full correlation of the obtained results
with the amount of the radioactive fall-out is observed. 相似文献
10.
Cesare Triulzi Silvia Giuliani Guogang Jia Marina Vaghi 《International journal of environmental analytical chemistry》2013,93(6-7):505-512
The primary objective of this study was to observe the evolution of anthropogenic radioactivity contamination in the Antarctic continent throughout the period 1997–1999. Moreover, results have been compared with those obtained for previous expeditions, starting from 1987. As far as 137Cs is concerned, interesting considerations could be made due to the great amount of available data. On the whole, radioactive contamination seems to be higher in continental than in marine environments. For lake algae, contamination seems to decrease gradually in the order: Tarn Flat, Edmondson Point, Carezza Lake. Focusing on 137Cs activity data, a clear temporal decreasing trend was observed in all samples: for sea water, values decreased from mean values of 0.9?Bq/m3 in 1987 to 0.5?Bq/m3 in 1999, a 56% decrease (20% of the total is due to natural decay of 137Cs). For lake waters and lake algae, the decreases are higher (80 and 30%, respectively) and the same can be assessed for sediments and soils, even if the resulting distributions are more complicated. The highest values for all radionuclides analysed were detected in terrestrial organisms (mosses, lake algae, and lichens). As a consequence, these matrices appear to be good bioindicators of radioactive contamination. Finally, although the Antarctic continent is affected by some degree by anthropogenic radioactive pollution, our results for 137Cs show that we are facing a progressive decrease. Moreover, contamination in other parts of the world is much higher: from 6–10 times in the Mediterranean Sea and 20–50 times in the North Sea and Black Sea. 相似文献
11.
M. G. Bettoli L. Cantelli M. Cecchini L. Tositti O. Tubertini S. Valcher 《International journal of environmental analytical chemistry》2013,93(1-4):253-260
Abstract 137 Cs activity in samples from lacustrine areas around the Italian base in Antarctica is reported as an integration of a previous work. Preliminary data of cosmogenic 7 Be activity determined in snowfalls, total atmospheric depositions, soil and air particulate collected during the 1990–91 and 1991–92 Italian expeditions in Antarctica is presented. The results obtained point out the efficiency of snow in the processes of air particulate scavenging and provide useful information for the development of research in Antarctica in the study of air/snow transfer processes by means of natural radionuclides. 相似文献
12.
Ayşegül Kahraman Gökay Kaynak Gizem Akkaya Orhan Gürler Sezai Yalçın 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):1057-1066
Activity concentrations of gross-β, naturally occurring 226Ra, 232Th, 210Pb, 7Be and anthropogenic 137Cs in epiphytic lichens collected from Uluda? Mountain are presented and discussed with the aim of evaluating potential usability of lichens as a biomonitor. The activity concentrations of gross-β, 137Cs, 40K, 226Ra, 232Th, 210Pb and 7Be in the lichen samples were found to be in the range of 177–707, 4.05–94.26, 86–211, below detection limit (BDL)—19.2, BDL—14.0, 229–872, and 72.1–220.7 Bq kg?1 in dry weight, respectively. 137Cs content in collected epiphytic lichens was in descending order: Parmelia sulcata > Lobaria pulmonaria > Pseudevernia furfuracea > Usnea filipendula. The best biomonitor for 137Cs among the lichen species used in this study was determined as Parmelia sulcata. Pearson’s correlation coefficient was calculated between 137Cs and 40K activity concentrations using a statistical package program (SPSS ver. 17.0) and a negative correlation value (R = ?0,323, p = 0,222) was obtained. The highest 226Ra and 232Th activity concentrations were found in Bo?azova Yaylas? which has a geological structure including granitic rocks. It was found that 137Cs and 7Be activity concentrations in species demonstrated an inverse behaviour. The effect of mean annual precipitation and temperature on 7Be activity concentration was determined using multi regression analysis. Also, correlations between the 137Cs and 7Be, and 40K and 7Be were investigated. 相似文献
13.
M. A. El-Absy M. A. El-Amir M. Mostafa A. A. Abdel Fattah H. M. Aly 《Journal of Radioanalytical and Nuclear Chemistry》2005,266(2):295-305
Summary Ruthenium-106 and 137Cs have been separated from thermal-neutron irradiated UO3 targets aged for ~2.5 years by distillation and surface interactions in nitrate media of controlled chemical composition.
After digestion of the aged targets with their aluminum wrapper in 2M NaOH solution, nitric acid was added to complete dissolution
of the formed residue. The prepared fission product solution was separated from 129I and 91.8% 106Ru by sequential distillation from 20% and 40% HNO3 solutions containing H2O2 and KMnO4, as oxidants, and by boiling for 4 and 2.5 hours, respectively. The recovery yield of 106Ru collected in 0.1M NaOH solution was ~68.2% with a radionuclidic purity of 399.99%. Thereafter, the fission product solution
was brought to pH 9.5 by addition of NaOH solution to precipitate Al(OH)3, MnO2, and Na2U2O7 which selectively retained the remaining fission products leaving, mainly, 137Cs in the supernatant solution. The recovery yield of 137Cs was ≥97.3% with ~99.75% radionuclidic purity. The gamma-ray emitter contaminants which could be detected and identified
in the recovered 137Cs solution, were ~0.25% 134Cs and ~1.4 . 10-3% 152,155Eu. 相似文献
14.
The transfer of 137Cs and 40K from soil to vegetation was studied in an Atlantic blanket bog ecosystem along the Atlantic coast of Ireland where the dominant
vegetation is a mixture of Calluna vulgaris, Eriophorum vaginatum and Sphagnum mosses. The impact of soil chemistry and nutritional status of vegetation on the uptake of both radionuclides was also examined.
Cesium-137 transfer factors values ranged from 1.9 to 9.6 and accumulation of 137Cs was higher in the leaves of C. vulgaris than in the stems. Transfer factors values for 137Cs in both C. vulgaris and E. vaginatum were similar indicating that for the vegetation studied, uptake is not dependent on plant species. The uptake of 137Cs in bog vegetation was found to be positively correlated with the nutrient status of vegetation, in particular the secondary
nutrients, calcium and magnesium. Potassium-40 transfer factors ranged from 0.9 to 13.8 and uptake was higher in E. vaginatum than in C. vulgaris, however, unlike 137Cs, the concentrations of 40K within the leaves and stems of C. vulgaris were similar. The concentration of both 137Cs and 40K found in moss samples were in general lower than those found in vascular plants. 相似文献
15.
Radiotracer batch ion‐exchange experiments were employed to investigate the uptake of 90Sr and 137Cs radioisotopes by various cation‐exchanged forms of a 30% cross‐linked macroporous 1‐vinyl‐2‐pyrrolidone–divinylbenzene cation‐exchange resin with 1.37 ml g?1 pore volume, 0.0232 µm pore diameter and 271.2 m2 g?1 surface area. The uptake of 90Sr and 137Cs was determined by taking liquid aliquots at various time intervals from solutions over solids. The volume‐to‐solid ratio was kept at 200. The results of kinetic experiments for the carrier‐free 90Sr and 137Cs were evident in all cationic forms of the resin. The percentage uptake and distribution coefficient Kd values with carrier (0.005 M SrCl2 and 0.01 M CsCl) concentrations were also determined, and the best results were obtained from the Li+ and H+ forms of the resin. Cerenkov counting (β?‐counting) was used to observe the initial and final radioactivity in the liquid phase. All the experiments were carried out at room temperature and the radioactivity in each case was corrected for the background counts. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
16.
G. N. Stradling P. G. Pellow A. Hodgson T. P. Fell A. Phipps M. Pearce M. Taskaeva I. Penev T. Guentchev 《Journal of Radioanalytical and Nuclear Chemistry》1997,226(1-2):7-14
The aim of this work was to provide an experimental basis for assessing intakes of an industrial actinide-bearing dust from measurements of60Co and137Cs in the body or urine. Whilst these radionuclides comprised 72% and 19% of the radioactivity present, greater than 90% of the committed effective dose will result from the low concentrations of the actinides present, 0.4%. To assess the dose coefficient for the dust and predict the biokinetics of60Co and137Cs in workers, absorption parameters for transfer from lungs to blood obtained from an animal study were combined with information on particle deposition and clearance from the ICRP human respiratory tract model and with tissue distribution and excretion data from the most recent systemic models. All other radionuclides were assumed to have Type M absorption characteristics. The dose coefficient for the dust, 1.29·10–7 Sv·Bq–1 was estimated to contain 113 kBq60Co, 29 kBq137Cs and 0.64 kBq of the actinides. The predicted retention and excretion characteristics of60Co and137Cs in workers after acute or chronic exposure to the dust suggested that measurements of these radionuclides in the body or urine could detect intakes equivalent to a few percent of an annual dose limit of 20 mSv·y–1. 相似文献
17.
M. K. Fasasi P. Tchokossa J. O. Ojo F. A. Balogun 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(3):949-952
The radioactivity of the Opa river — irrigated farmlands in the south western Nigeria was determined using an HpGe based,
low-level passive gamma-counting system. With the exception of two isotopes, the main radionuclides analysed in the sample
were the progenies of238U and232Th. The other two isotopes were the naturally occurring40K and the anthropogenic137Cs. The result obtained showed elevated levels of radioactivity from all detected radionuclides compared to the published
data for this area. Enhanced levels of naturally occurring radionuclides is attributed to the use of phosphatic fertilizers
for dry season vegetable cultivation along this river banks. The presence of the fission product137Cs could be traced to the fallouts occasioned by the various French nuclear tests in the Sahara desert, and probably, some
effect of the more recent nuclear reactor accident at Chernobyl in 1986. 相似文献
18.
Two sediment cores were recovered in San Simón Bay (NW Spain) in order to establish sediment accumulation rates by 210Pb and 137Cs dating and to reconstruct metal pollution history. Sediment composition was determined by X-ray Fluorescence. A main lithogenic
origin was shown up. Grain size conditions radionuclide activities and element concentrations. Fine grained sediments concentrate
pollutants and showed higher activities. Radionuclide profiles are affected by diagenetic processes and sedimentary disturbances,
but a temporal framework could be obtained for the intertidal area, where the anthropogenic inputs of Cu, Pb and Zn started
several decades ago. 相似文献
19.
Gye-Nam Kim Suk-Chol Lee Dong-Bin Shon Hye-Min Park Wang-Kyu Choi Jei-Kwon Moon 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(1):121-128
For the disposal of the high efficiency particulate air (HEPA) glass filter to environment, the glass fiber should be leached
to lower its radioactive concentration. To derive the optimum method for removal of Co and Cs from HEPA glass fiber, four
methods were applied in this study. Results of electrochemical leaching of glass fiber by 4.0 M HNO3–0.1 M Ce(IV) solution showed that the removal efficiency of 134Cs, 137Cs, and 60Cs from glass fiber after 5 h was 96.4, 93.6, and 93.8%, respectively. Results by 5 wt% NaOH solution showed that the removal
efficiency of 134Cs, 137Cs, and 60Cs after 30 h was 81.7, 82.1, and 10.0%, respectively. Results by repeat 2.0 M HNO3 solution showed that the removal efficiencies of 134Cs, 137Cs, and 60Cs after 2 h of three repetitions were 96.2, 99.4, and 99.1%, respectively. Finally, results by repeat 4.0 M HNO3 solution showed that the removal efficiencies of 134Cs, 137Cs, and 60Cs after 4 h of three repetitions were 100, 99.9, and 99.9%, respectively, and their radioactivities were below 0.1 Bq/g.
Therefore, the chemical leaching method by 4.0 M HNO3 solution was considered as an optimum one for removal of cesium and cobalt from HEPA glass fiber for self disposal. Also
the removal efficiencies of 60Co, 134Cs, and 137Cs from the waste-solution after its precipitation-filtration treatment for reuse of 4.0 M HNO3 waste-solution were 88.0, 95.0, and 99.8%. 相似文献
20.
To examine the radionuclide concentrations in the environment, seaweeds were collected once a year since 1976 at two different places. A marked change was observed in the number of radionuclides in seaweeds. The increase of radionuclides is attributed to contamination by radioactive fallout from Chinese nuclear explosion tests. The radionuclide concentrations were strongly dependent on the species of seaweeds. A gradual decrease of the137Cs/40K activity ratio was observed in spite of the input of additional137Cs fallout from Chinese nuclear tests. This implies that the amounts of137Cs introduced into seawater by these detonations were small in comparison with those already contained in seawater. The cesium content in seawater was estimated by using specific activities of137Cs in seaweeds and137Cs concentration in seawater. The results show good agreement with the reported values by direct analysis of seawater. 相似文献