2001 Chemical availability of 137Cs and 90Sr in.pdf (original) (raw)
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RAD Conference Proceedings, 2016
In this study we investigated artificial (137 Cs, 90 Sr) and natural (40 K) radioisotopes' vertical distribution in different usage soils. Soil samples were collected in Lithuanian territory, which was, after the nuclear weapons and the Chernobyl Nuclear Power Plant (ChNPP) accident, contaminated with artificial radionuclides. For the study, three places were selected, taking into account human activities and radioactive environmental contamination (Neris Regional Park, a field near the Ignalina nuclear power plant and a field in a village in Ukmergė district). In addition, we analysed the soil organic matter, which determines the amount of nutrients, water infiltration, ion exchange, adsorption of pollutants. Studies show that in those places the predominant soil type is sandy loam, with soil mineralization rate close to 1. In the village place and the regional park place (respectively Jogvilai and Paaliosė areas), 137 Cs specific activity decreases exponentially. However in the village place (Paaliosė), at 10-15 cm soil depth, there is a noticeable increase in the specific activity of 137 Cs, associated with the former nuclear weapons test contamination. 40 K changes the specific activity of the soil samples taken from the depth in all areas. In the village place (Paaliosė), and the field near the Ignalina nuclear power plant (Stabatiškės), 40 K specific activity decrease with the increase of depth was observed, and in the field in the village in Ukmergė district (Jogvilai) it was vice versawith the increase of depth, 40 K specific activity increases. The average 90 Sr radionuclides in the soil are 6,4±1,1 Bq/kg (in the village place (Paaliosė)) 6,4±2,0 Bq/kg (field near Ignalina nuclear power plant) and 11,3±1,7 Bq / kg (the field in the village in Ukmergė district).
Eurasian Soil Science, 2020
Concurrent with the Chernobyl accident along the explosions caused by nuclear tests and advances in nuclear sciences, researchers around the world have been trying to examine the potential of fallout radionuclides for accurate estimation of soil erosion and redistribution. The inadequacy of the existence of radionuclides and the complexity of factors affecting the amount of these elements in soil are among the important limiting factors in usage of radionuclide materials in soil erosion studies. As the most widely used radionuclides in soil erosion studies, 137 Cs and 210 Pb come from two different origins of anthropogenic and geogenic, respectively. Since the 137 Cs and 210 Pb excess reach the soil surface mainly through precipitation, the climate and latitude play important roles on the existence of radionuclides in the soil. Due to the location of the point sources of 137 Cs, the coordinates of the site under consideration and the wind regimes can also be very important to affect the precipitation and consequently, the inventories of 137 Cs. Awareness of the range of possible changes of 137 Cs and 210 Pb excess in undisturbed soil is an important step to improve and validate soil erosion estimation results. Accordingly, the present research reviews the data of the mean annual precipitation and inventory of 137 Cs and 210 Pb excess in undisturbed soil and presents some regression equations for different climates and latitudinal zones of the world. Based on the results, the inventory of 137 Cs in undisturbed soil can be estimated statistically acceptable only in two latitudinal zones of 16°-25° N and 26°-35° N. While due to the small amount of data and the impossibility of data separation for different zones and climates, the inventory of 210 Pb excess can be estimated statistically acceptable given all the data without considering the latitudinal zones. The estimations of the inventories of 137 Cs and 210 Pb excess in undisturbed soil is statistically acceptable in two temperate and continental climates and only temperate climate, respectively.
Scientific Reports
the aims of this study were to investigate the vertical distributions of natural radionuclides 232 Th, 226 Ra and 40 K as well as anthropogenic radionuclide 137 cs in soil samples and to analyze the correlation among the radioactivity of these radionuclides and the physiochemical characteristics of soil samples namely pH, grain size, carbonate content and organic matter. Risk assessment of the radiological hazard has also been estimated. forty-four soil samples were collected from eleven locations in Qatar at four depth levels from 0 to 16 cm. The average concentrations of 232 Th, 226 Ra, 40 K and 137 cs in the soil depth of 16 cm were 10, 17, 201 and 4 Bq/kg, respectively, which were within the reported world mean. The external absorbed gamma dose rate, the annual effective dose, the mean radium equivalent activity, the external hazard index and the lifetime cancer risk were 22 nGy/h, 0.027 mSv/y, 47 Bq/ kg, 0.125 and 0.096 × 10 −3 , respectively. These values were far below the minimum recommended international values. The level of radioactivity concentrations in the soil was affected by the physiochemical characteristics of the soil. the positive correlation with highest R 2 value was found among the radioactivity concentrations of 232 th and 40 K and the soil clay content. total organic carbon was also positively correlated for 226 Ra and 137 Cs activity concentrations, whereas, carbonate content was negatively correlated with the radioactivity concentrations of 232 th and 40 K. As far as soil moisture content is concerned, the positive correlation with highest R 2 value was obtained for 226 Ra activity concentrations. Radioactivity has become an issue of major concern over the years due to its association with human health 1,2. Natural and artificial radioactive isotopes are host in the environment. Radionuclides, with different biogeochemical processes and important movability, can influence the environment through bioaccumulation and are hazardous for the environment and human health. The radioactive isotopes in the environment cause the external radiation dose to human organisms, while the isotopes integrated by inhalation and ingestion are the origin of the internal radiation dose. Studies about dose-effect relationships of radioactive materials have helped to increase knowledge about the risks associated with radiations and have played an important role in developing radiation protection regulations. Characteristic of soil is instantaneously concerned to the essence of life 3. The risk from Cs-137 varies with its diffusion rates in soil. If Cs-137 migrate slowly in soil, the internal irradiation will be higher due to higher absorption by plants roots especially from the top surface of 5 cm depth. However, if Cs-137 diffuse rapidly, the external radiation will be less as in this case, the uppermost soil surface acts as a shield against radioactivity found in deeper soil layers 4. Therefore, assessment of the diffusion of natural and artificial radionuclides in soil is important to protect human and environment 5. Naturally Occurring Radioactive Materials (NORM) refers to the natural origins of radiations i.e. from naturally occurring radioisotopes 6. Natural radioactivity can result from cosmogenic radioactive isotopes which are continuously produced by the effect of cosmic radiation (e.g.
Time dependence of the transfer factor of 137Cs from surface soil to plants
The Science of The Total Environment, 1993
The time dependence of the availability of 137Cs in soil for root uptake by plants was studied. This was accomplished by taking advantage of the prolonged droug~ t in Greece during the years 1986-1990 in order to simulate the chemical evolution of caesiu~n in soil. Several measurements of the soil to plant transfer factor were performed on a lake bottom, exposed due to the drought since 1986. T.te transfer factor for caesium to vegetation growing on recently exposed lake bottoms was found to be three to five times higher than the transfer factor to vegetation growing on areas that had dried up for more than 2 years. These results support the premise that with the passage of time radiocaesium from nuclear fallout is trapped in surface soil and thus becomes less available for uptake by vegetation.
Accumulation and translocation peculiarities of 137Cs and 40K in the soil – plant system
Journal of Environmental Radioactivity, 2015
Cs 40 K System soil-plant Different ecotopes a b s t r a c t Long-term investigations (1996e2008) were conducted into the 137 Cs and 40 K in the soil of forests, swamps and meadows in different regions of Lithuania, as well as in the plants growing in these media. The 137 Cs and 40 K activity concentrations, the 137 Cs/ 40 K activity concentration ratio and accumulation, and translocation in the system, i.e. from the soil to plant roots to above-ground plant part of these radionuclides, were evaluated after gamma-spectrometric measurements using a high purity germanium (HPGe) detector.
Transfer of 137Cs from soil to vegetative crops
The researches for the transfer of radio-nuclides from the soil to the plant have great importance in terms of assessment of radiation risk, for formation of preventive measures in accidents as well as for eventual decontamination of the land by growing certain plants.Taking into consideration the importance of the distribution and the transfer of radionuclides from the soil to the vegetative crops, in this work an attempt was made to calculate the transfer factor of l37Cs from soil to plant.Data have been used about concentrations of activities of soil from certain locations in the surrounding area of Skopje, their mean value has been taken, while the values of the transfer factors of radio-nuclides from soil to plant have been taken from international scales, for grain and corn. It is assumed that in Macedonia they represent most commonly used vegetative crops, so the grain and the stem of the plant have been separately analyzed. The radiometric analysis of these samples were performed by using of gamma spectrometer supplied with germanium of high purity (HPGe), detector with 30% relative efficiency and energetic resolution (FWHM) of 1.8 keV for 1.33 MeV reference point of 60Co. The software applied for obtaining data is Canberra software package, Genie-2000, including search of maximal value and modules for identification of nuclides. The results indicate that 137Cs is accumulated more in the root than in the grain which would imply control of the radioactivity in the agricultural land. Also these data may represent a basis for assessment of a dose that the population receives by ingestion of produced food, which required knowledge about the average annual intake for every plant separately.
2020
Radioactive cesium (137Cs) in distinct soil fractions provides key information to its bioavailability, and therefore determining the effect of soil characteristics and land use types on existing fractions of 137Cs in soils is important for predicting future 137Cs mobility in Fukushima. Thus, the objective of this study was to investigate the influence of soil characteristics and land use types on sequentially extracted fractions of 137Cs in Fukushima. In this study, five coniferous forest soils, eight arable soils, and eight paddy rice soils were sampled in 2012 and 2013. The 137Cs in the soils were separated into four fractions; water-soluble, exchangeable, organic matter-bound and residual fractions. More than 90% of the soil 137Cs fraction for arable and paddy rice soils was found in the residual fraction, implying significantly reduced bioavailable 137Cs with higher fixation. In contrast, forest soils measured higher exchangeable and organic matter-bound fractions of 5%–33% and ...
Journal of environmental radioactivity, 2015
We monitored the vertical distribution of (137)Cs in soil profiles under eight different land uses for the 2 y after the Fukushima Dai-ichi Nuclear Power Plant accident, and discussed the temporal changes in the early-stage of the migration and the determinants of the initial distribution. The soil samples were collected for four surveys using a scraper plate at each study site, which consisted of three forests (mixed forest, mature cedar, and young cedar), two grasslands (pasture and meadow) and three abandoned agricultural fields (farm land, tobacco field, and paddy field). The land use patterns have a large influence on some soil properties and the migration processes of (137)Cs above ground, resulting in different distribution of (137)Cs in those soil profiles. Specifically, the secondary deposition of (137)Cs from the coniferous canopy, retention of (137)Cs by litter layer, and the homogenization of (137)Cs concentrations in surface soil by natural soil mixing such as the distu...