Levels Of 137Cs Research Articles

Особенности и возможность химической модификации поведенческих реакций в приподнятом крестообразном лабиринте хронически облученных мышей с различной генетически детерминированной радиочувствительностью

Structural elements of the central nervous system--neurons, along with the higher neuroendocrine structures and the hypothalamus centres, show high sensitivity to a chronic action of low doses of ionizing radiation (IR) in view of their extreme enrichment by phospholipids and intensive supply by oxygen, creating favorable conditions for the development of oxidizing stress. Stressful influences cause negative emotions in the behaviour of animals manifested as fear or uneasiness. The study represents the results of comparative research into the behavioral reactions characterized by uneasiness in the Balb/c and C57bl/6 mice exposed to a chronic irradiation at low doses. The chitin-melanin-glucan complex from fungi Fomes fomentarius (ChMG) was approved as an adaptive agent. It has been shown that under identical conditions, deposition levels of radionuclides 137Cs and 90Sr are raised in mice with IR hypersensitivity--line Balb/c, in comparison with less radio sensitive mice--line C57bl/6. Simultaneously, Balb/c mice were observed to exhibit the signs of a more anxious behaviour in the new environment. Chronic external and internal radiation exposure to rare ionizing radiation at low doses promotes strengthening of anxiety and phobic reactions in mice with IR hypersensitivity. The use of ChMG in animals neutralized the increase in anxiety and phobic reactions after a prolonged irradiation, thus indicating the presence in ChMG of the anxiolitic activity along with the above mentioned powerful radiosorbent, antioxidant, gene protective and immunomodulatory properties.

Radionuclide mapping of the Molise region (Central Italy) via gamma-ray spectrometry of soil samples: relationship with geological and pedological parameters

Radionuclide maps of the Molise region were created for the first time using gamma-ray spectrometry analysis of 205 soil samples. The geographical distributions of 40K, 232Th and 238U were within the world average values for soils. 40K was distributed homogeneously with a slight enhancement along the coastline. The decay chains of 238U and 232Th were in secular equilibrium with their daughters, also showing a homogeneous distribution except for localized areas of enhanced concentrations close to the borders with the Lazio and the Campania regions. Concentrations of all three radionuclides were correlated with geological and pedological characteristics of soils. The measured external gamma-dose rate in the air due to naturally occurring radionuclides in the soil, and the dose rate due to cosmic rays were in agreement with values measured in other Mediterranean regions. Increased 137Cs levels from atmospheric nuclear weapons tests and the Chernobyl fallout were found at sites above 1,000 m a.s.l.

Seasonal variation of the 137Cs level and its relationship with potassium and carbon levels in conifer needles

Seasonal variations in foliar 137Cs levels were examined in Norway spruce (Picea abies (L.) Karst.), and Scots pine (Pinus sylvestris L.) in western Finland. Our aim was to test the occurrence of seasonal variation in contents and concentrations of 137Cs, potassium and carbon in needles. The study focused on analysing levels of total 137Cs in the three youngest needle age classes and comparing them to the levels of potassium and carbon. Spruce and pine needles were collected from 50- and 65-year-old stands on 18 sampling occasions between April 1996 and February 1997. Phases of intensive growth, needle elongation and dormancy were apparent in the time series for the needle contents and activity concentration of 137Cs, both of which varied according to needle age class and tree species. The sequence of phases with a temporal fluctuation of needle contents, activity concentrations of 137Cs and concentrations of K and carbon varied occasionally, and the efficiency of their translocation revealed some differences in the dynamics of 137Cs, K and carbon in spruce and pine. The data clearly showed that the needles' K contents responded strongly to changes in K demand from other parts of the tree due to seasonal changes and that these responses were stronger than the associated retranslocations of 137Cs, particularly in Scots pine. During intensive growth, K was less mobile than 137Cs in the needles. The uptake of 137Cs by current-year needles is simultaneously affected by uptake from the soil via the roots and retranslocation from other internal sources, and both of these processes affect the observed transfer rates during the growth period. Our results provided information on the transfer rates and revealed differentiation of root uptake and retranslocation of 137Cs in needles. The study can support dynamic modelling of atmospheric 137Cs contamination in forests.

Land use effects on erosion and carbon storage of the Río Chimbo watershed, Ecuador

Soil carbon storage is an important component of global carbon cycling. Andean Andisols have high carbon content and are vulnerable to erosion because of agricultural intensification and deforestation. This study examines the effects of land use on erosion and soil carbon storage in the Rio Chimbo watershed of Ecuador. Soil carbon content, age, and erosion estimated from 137Cs inventories was measured along an elevational transect under annual cropping, natural forest, paramo, pasture, and tree plantations. Land use, particularly annual cropping, affected 137Cs levels in the upper soil layers, but did not have an impact on total carbon storage to a depth of 1 m. Relative erosion rates estimated from 137Cs inventories at sites under annual cropping averaged 27 t ha−1 y−1 over the erosion rate of non-cultivated sites. A linear relationship was observed between soil carbon age (determined by 14C levels) and 137Cs levels, where pasture sites had lower 137Cs and older carbon compared to natural forest sites. The effects of land use on soil loss in the Rio Chimbo watershed suggest a loss and/or removal of soil carbon, particularly under annual cropping.

Radioactivity levels and radiation hazard of healing mud from San Diego River, Cuba

Healing mud core samples were collected in the San Diego River (Southwest Cuba), in order to determine the behaviour of the radioactivity levels of 226Ra, 137Cs, 232Th and 40K and to evaluate their possible radiological impact on peloide therapeutic uses. The radionuclide concentration ranges in healing mud profiles on Bq kg−1 dry weight varied as follows: 226Ra = 22–26, 137Cs = 4.6–33.0, 232Th = 18–31 and 40K = 208–433. The calculated average radium equivalent activity (82 Bq kg−1), total absorbed dose rate (40 nGy h−1), external hazard index (0.23), annual gonadal dose equivalent (280 μSv h−1) and annual effective dose equivalent (48.5 μSv y−1) are less than international recommended values. Hence, the levels of radioactivity in healing muds from San Diego River are not an impediment for its use for medical proposes.

Spatial distribution and accumulation of 226Ra, 228Ra, 40K and 137Cs in bottom sediments of Mumbai Harbour Bay

The present work shows the activity levels of 226Ra, 228Ra, 40K and 137Cs in bottom sediments collected from eight locations of Mumbai Harbour Bay. The study has shown that 40K and 228Ra concentration is nearly uniform throughout the studied area while 226Ra and 137Cs are more concentrated in the southern regions of the bay. The significant variation in the activity levels of radionuclides within the study site might be due to their sorption/desorption processes onto the surface of sediment materials. The low mean value of 226Ra/228Ra ratio (0.72) in the sediments indicates that 238U has relatively greater solubility and mobility than 232Th. Similarly, low activity ratio (0.18) for 137Cs/40K reflects the presence of very high content of 40K in sediment due to presence of primary minerals in sediment. Silt and clay were reported to dominate the composition of the sediment. A significant positive correlation between 226Ra and 228Ra and 137Cs and 40K suggest a similar origin of their geochemical sources and identical behavior during transport in the sediment system.

Pre- and post-Chernobyl accident levels of 129I and 137Cs in the Southern Baltic Sea by brown seaweed Fucus vesiculosus

129I is a very long-lived radionuclide (T1/2 = 15.7 × 106 years) that is present in the environment both because of natural and anthropogenic sources. In this work 129I concentration and 129I/127I ratio have been determined in seaweed Fucus vesiculosus collected in the Southern Baltic Sea during 1982 and 1986 (post-Chernobyl accident). The resulting data were evaluated in terms of 129I concentrations, 129I/127I and 129I/137Cs ratios. 129I concentrations were found to be in the order of (0.82–5.89) × 109 atoms g−1 in 1982 and (1.33–38.83) × 109 atoms g−1 in 1986. The 129I/127I ratios ranged from (22.7–87.8) × 10−10 for seaweed collected in 1982 and from (26.1–305.5) × 10-10 for seaweed collected in 1986. Also a linear relationship was established for 127I concentrations in seawater and salinity in this area, enabling the estimation of concentration factors for 127I in F. vesiculosus.The high levels of 129I and 129I/127I in the Kattegat and their gradually decreasing trend to the Baltic Sea indicates that the most important contribution to the 129I inventory in the Baltic Sea area comes from Sellafield and La Hague reprocessing plants. With respect to Chernobyl accident, 129I concentrations in samples collected in 1986 were not much higher than those expected in less contaminated samples from 1982. This supports the view that the contribution of the Chernobyl accident to 129I in the Baltic region was not significant.

The ambient gamma dose-rate and the inventory of fission products estimations with the soil samples collected at Canadian embassy in Tokyo during Fukushima nuclear accident

In this study, soil samples were collected at Canadian embassy in Tokyo (about 300 km from Fukushima) on 23 March and 23 May of 2011 for purposes of estimating concentrations of radionuclides in fallout, the total fallout inventory, the depth distribution of radionuclide of interest and the elevated ambient gamma dose-rate at this limited location. Some fission products and actinides were analyzed using gamma-ray spectrometry, alpha spectrometry and liquid scintillation counting. The elevated activity concentration levels of 131I, 132I, 134Cs, 137Cs, 136Cs, 132Te, 129mTe, 129Te, 140Ba and 140La were measured by the gamma-ray spectrometer in the first sample collected on 23 March. Two months after the accident, the 134Cs and 137Cs became only detectable nuclides. A mass relaxation depth of 3.0 g/cm2 was determined by the activities on the depth distribution of 137Cs in a soil core. The total fallout inventory was thus calculated as 225 kBq/m2 on March sampling date and 25 kBq/m2 on May sampling date. The ambient gamma dose-rates in the sampling area estimated by the fallout fission products inventory and 137Cs depth distribution ranged from 184 to 38 nGy/h. There was no detectable americium or plutonium in the soil samples by alpha spectrometry. Although 90Sr or 89Sr were detected supposedly as a result of this accident, it was less than the detection limit, which was about 0.4 Bq/kg in the soil samples.

Radioisotopic and physicochemical background indicators to assess soil degradation affecting olive orchards in southern Spain

Soil degradation is a major agrienvironmental issue under Mediterranean climatic conditions. To assess soil erosion magnitude under orchard plantation, soils in an undisturbed area – located within an archaeological protected site in southern Spain – were analysed to establish its physicochemical status, the initial 137Cs fallout and the natural level of radioactivity taking into account the content of naturally occurring radionuclides (NOR). The vertical profiles of NOR mass activities confirmed its non-disturbance. 90% of the 137Cs content was concentrated in the top 20cm and the physicochemical parameters confirmed as well the undisturbed status of the site. The base-line level of 137Cs was established at 1925±250Bqm−2 with a coefficient of variation of 23% and an allowable error of 11%. This 137Cs background was used to assess soil erosion magnitude in a close orchard field using the 137Cs method. The maximum erosion rates reached 19t−1ha−1yr−1 and a sediment delivery ratio of 29% was evaluated, both values confirming an unsustainable soil loss magnitude due to the combination of water and tillage erosion processes since the 1950s. The radium equivalent activity and the absorbed dose rate results highlighted a difference between eroded and deposition sectors in the cultivated field confirming that these parameters could be used to some extend to assess pedologic processes.

Artificial and natural radioactivity in edible mushrooms from Sao Paulo, Brazil

Environmental biomonitoring has demonstrated that organisms such as crustaceans, fish and mushrooms are useful to evaluate and monitor both ecosystem contamination and quality. Particularly, some mushroom species have a high capacity to retain radionuclides and some toxic elements from the soil and the air. The potential of mushrooms to accumulate radionuclides in their fruit-bodies has been well documented. However, there are no studies that determine natural and artificial radionuclide composition in edible mushrooms, in Brazil. Artificial (137Cs) and natural radioactivity (40K, 226Ra, 228Ra) were determined in 17 mushroom samples from 3 commercialized edible mushroom species. The edible mushrooms collected were Agaricus sp., Pleurotus sp. and Lentinula sp. species. The activity measurements were carried out by gamma spectrometry. The levels of 137Cs varied from 1.45 ± 0.04 to 10.6 ± 0.3Bqkg−1, 40K levels varied from 461±2 to 1535 ± 10Bqkg−1, 226Ra levels varied from 14 ± 3 to 66 ± 12Bqkg−1 and 228Ra levels varied from 6.2 ± 0.2 to 54.2 ± 1.7Bqkg−1. 137Cs levels in Brazilian mushrooms are in accordance with the radioactive fallout in the Southern Hemisphere. The artificial and natural activities determined in this study were found to be below the maximum permissible levels as established by national legislation. Thus, these mushroom species can be normally consumed by the population without any apparent risks to human health.

Spatial distributions of 137Cs in surface soil in Jing-Jin-Ji Region, North China

Artificial Radiocaesium (137Cs) has been widely deposited over global soils. In this study, we measured 137Cs activity concentrations in the soil samples taken from Jing-Jin-Ji Region, North China, during 2007–2008. The surface soil (0–20cm) samples were collected from 452 sites in this region. The activity concentration of 137Cs in the samples was measured using a GEM series HPGe (high-purity germanium) coaxial detector system (ADCOM-100). The main findings are as following. (1) The activity concentration of 137Cs in surface soils in the region of study fluctuates within 0.3±0.1 to 12.9±0.4Bq/kg with mean value of 3.7Bq/kg. Compared to other regions located at roughly the same latitude, the 137Cs activity is relatively low. The results indicate that there are no new inputs of the radionuclides into the area at that time and the data obtained could serve as baseline levels of 137Cs in Jing-Jin-Ji Region. (2) Considering land use types, surface soil in woodland mostly shows high 137Cs activities with rare natural erosion and anthropogenic activities, and the surface soil with relatively low 137Cs activities appears in the areas of intensive anthropogenic activities, especially in the cities, river banks, reservoirs and the strongly eroded areas. The findings suggest that the varying distribution of 137Cs activities in surface soil corresponds with land use types.

Resuspension processes controll variations of 137Cs activity concentrations in the ground-level air

The 137Cs activity concentration in the surface air between 1977 and 2007 was decreasing with an ecological half-life of 3.4 years, however, during 2007–2010 the yearly averaged 137Cs activity concentrations were almost constant. The increased atmospheric 137Cs and 40K levels observed during the winter may be due to surface soil resuspension and radionuclide transport by winds, particularly from open agricultural areas, as confirmed by high correlation coefficient between 137Cs and 40K atmospheric levels (R = 0.84), and similar 137Cs/40K activity ratios in aerosols (0.07) and soils (0.05).

Long-term simulations of the 137Cs dispersion from the Fukushima accident in the world ocean

The LAMER calculation code was used for simulation of the distribution of 137Cs released after the Fukushima accident into the Pacific and Indian Oceans. The maximum 137Cs concentration predicted for surface waters of the open NW Pacific Ocean in 2012 (21Bq/m3 at 38°N, 164°E) will be comparable to that observed during the early 1960s after atmospheric nuclear weapons tests. The 137Cs in surface waters of the Pacific Ocean will reach the US coast 4–5y after the accident, however, the levels will be low (<3Bq/m3). All the North Pacific Ocean will be labeled with Fukushima 137Cs 10y after the accident with concentrations below 1Bq/m3. Thirty years after the accident the 137Cs levels in the Pacific and Indian Oceans will be below 0.1Bq/m3, i.e. undetectable on the present global fallout background. The effective dose commitment with ingestion of marine biota found in 2012 in the open NW Pacific Ocean was estimated to be 1.7μSv/y, mostly delivered by 134,137Cs. The estimated dose is by about a factor of 500 lower than the present dose limit for the public.

Low levels of 134Cs and 137Cs in surface seawaters around the Japanese Archipelago after the Fukushima Dai-ichi Nuclear Power Plant accident in 2011

Copyright © 2012 by The Geochemical Society of Japan. and mixing. While the 134Cs and 137Cs concentrations of highly contaminated surface seawater samples around the FDNPP have been studied extensively (Tsumune et al., 2012; Honda et al., 2012), relatively little information is available on radionuclide concentrations in seawater for other sea areas around the Japanese Archipelago. We previously reported low levels of 134Cs and 137Cs concentrations in surface water samples from the Pacific Ocean side of northeastern Japan, the Japan Sea, and the southwestern Okhotsk Sea before and after the FDNPP accident; however, the scope of these studies was somewhat cursory (Inoue et al., 2012a, b). Nonetheless, these studies illustrated the need for more extensive temporal and spatial investigations to assess the oceanic behaviors and fate of Fukushima-derived radionuclides around the Japanese Islands. We therefore used low-background γ-spectrometry to characterize the lateral variations of 134Cs and 137Cs concentrations in surface waters around the Japanese Archipelago in June and October 2011. These data were combined with 134Cs deposition data (Ministry of Education, Low levels of 134Cs and 137Cs in surface seawaters around the Japanese Archipelago after the Fukushima Dai-ichi Nuclear Power Plant accident in 2011

Radioactive fallout in the United States due to the Fukushima nuclear plant accident

The release of radioactivity into the atmosphere from the damaged Fukushima Daiichi nuclear power plant started on March 12th, 2011. Among the various radionuclides released, iodine -131 ((131)I) and cesium isotopes ((137)Cs and (134)Cs) were transported across the Pacific Ocean and reached the United States on 17-18 March 2011. Consequently, an elevated level of fission products (131)I, (132)I, (132)Te, (134)Cs and (137)Cs were detected in air, water, and milk samples collected across the United States between March 17 and April 4, 2011. The continuous monitoring of activities over a period of 25 days and spatial variations across more than 100 sampling locations in the United States made it possible to characterize the contaminated air masses. For the entire period, the highest detected activity values ranged from less than 1 m Bq m(-3) to 31 m Bq m(-3) for the particulate (131)I, and up to 96 m Bq m(-3) for the gaseous (131)I fraction.

Preliminary assessment of ecological exposure of adult residents in Fukushima Prefecture to radioactive cesium through ingestion and inhalation

ObjectiveThis study aims to estimate the ecological exposure of adult residents of Fukushima Prefecture to 134cesium (Cs) and 137Cs through ingestion and inhalation between July 2 and July 8, 2011.MethodsFifty-five sets of meals with tap water, each representing one person’s daily intake, were purchased in local towns in Fukushima Prefecture. Locally produced cow’s milk (21 samples) and vegetables (43 samples) were also purchased. In parallel, air sampling was conducted at 12 different sites using a high-volume sampler. Nineteen sets of control meals were collected in Kyoto in July 2011. 134Cs and 137Cs levels in the samples were measured using a germanium detector.ResultsRadioactivity was detected in 36 of the 55 sample meals from Fukushima, compared with one of 19 controls from Kyoto. The median estimated dose level (μSv/year) was 3.0, ranging from not detectable to 83.1. None of the cow’s milk (21) or vegetable (49) samples showed levels of contamination above the current recommended limits (Bq/kg) of 200 for milk and 500 for vegetables. The total effective dose levels by inhalation were estimated to be <3 μSv/year at nine locations, but samples at three other locations close to the edge of the 20-km radius from the crippled nuclear power plant showed higher levels of contamination (μSv/year): 14.7 at Iitate, 76.9 at Namie, and 27.7 at Katsurao.ConclusionsLevels of exposure to 134Cs and 137Cs in Fukushima by ingestion and inhalation are discernible, but generally within recommended limits.Electronic supplementary materialThe online version of this article (doi:10.1007/s12199-011-0251-9) contains supplementary material, which is available to authorized users.

Impacts of the Fukushima Nuclear Power Plants on Marine Radioactivity

The impacts on the ocean of releases of radionuclides from the Fukushima Dai-ichi nuclear power plants remain unclear. However, information has been made public regarding the concentrations of radioactive isotopes of iodine and cesium in ocean water near the discharge point. These data allow us to draw some basic conclusions about the relative levels of radionuclides released which can be compared to prior ocean studies and be used to address dose consequences as discussed by Garnier-Laplace et al. in this journal. The data show peak ocean discharges in early April, one month after the earthquake and a factor of 1000 decrease in the month following. Interestingly, the concentrations through the end of July remain higher than expected implying continued releases from the reactors or other contaminated sources, such as groundwater or coastal sediments. By July, levels of (137)Cs are still more than 10,000 times higher than levels measured in 2010 in the coastal waters off Japan. Although some radionuclides are significantly elevated, dose calculations suggest minimal impact on marine biota or humans due to direct exposure in surrounding ocean waters, though considerations for biological uptake and consumption of seafood are discussed and further study is warranted.

Food safety regulations: what we learned from the Fukushima nuclear accident

On 11 March 2011, the magnitude-9.0 earthquake and a substantial tsunami struck off the northeast coast of Japan. The Fukushima nuclear power plants were inundated and stricken, followed by radionuclide releases outside the crippled reactors. Provisional regulation values for radioactivity in food and drink were set on 17 March and were adopted from the preset index values, except that for radioiodines in water and milk ingested by infants. For radiocesiums, uranium, plutonium and transuranic α emitters, index values were defined in all food and drink not to exceed a committed effective dose of 5 mSv/year. Index values for radioiodines were defined not to exceed a committed equivalent dose to the thyroid of 50 mSv/year, and set in water, milk and some vegetables, but not in other foodstuffs. Index values were calculated as radioactive concentrations of indicator radionuclides (131I for radioiodines, 134Cs and 137Cs for radiocesiums) by postulating the relative radioactive concentration of coexisting radionuclides (e.g., 132I, 133I, 134I, 135I and 132Te for 131I). Surveys were thence conducted to monitor levels of 131I, 134Cs and 137Cs. Provisional regulation values were exceeded in tap water, raw milk and some vegetables, and restrictions on distribution and consumption began on 21 March. Fish contaminated with radioiodines at levels of concern were then detected, so that the provisional regulation value for radioiodines in seafood adopted from that in vegetables were additionally set on 5 April. Overall, restrictions started within 25 days after the first excess in each food or drink item, and maximum levels were detected in leafy vegetables (54,100 Bq/kg for 131I, and a total of 82,000 Bq/kg for 134Cs and 137Cs). This paper focuses on the logic behind such food safety regulations, and discusses its underlying issues. The outlines of the food monitoring results for 24,685 samples and the enforced restrictions will also be described.

Long-term variations of 14C and 137Cs in the Bratislava air – implications of different atmospheric transport processes

This study summarizes measurements of atmospheric 14C and 137Cs in the Bratislava air since 1976. Higher 14C levels observed in spring and early summer months until the 1980’s confirm injection of the stratospheric air into the troposphere. Later, deep winter minima were observed in 14C concentrations, probably due to the depletion of the atmospheric 14C levels in winter months by the injection of large quantities of fossil CO2. Presently observed 14C maxima in summer and minima in winter were caused by the depletion of the atmospheric 14C in winter months, amplified by temperature inversions during winter, rather than by the injection of the stratospheric air into the troposphere. The observed 137Cs activity concentrations also showed an impact of the stratospheric air on the 137Cs levels until the early 1980’s, documented by typical spring/early summer maxima and winter minima. The global fallout 137Cs record was then disturbed by the Chernobyl accident (1986) when large quantities of 137Cs were released to the atmosphere. The recent 137Cs variations observed in the atmosphere, characterised by winter maxima and summer minima, are assumed to be mainly due to the resuspension of 137Cs from the soil. A correlation was found between the 137Cs activity concentration and the dust level in the air (the correlation coefficient r = 0.74), as well as an anticorrelation with the temperature (r = −0.56).

Airborne radionuclides in mosses collected at different latitudes

Terrestrial mosses are a promising medium for investigation and monitoring of airborne radionuclide depositions due to their widespread occurrence, ease of sampling, and the possibility of high-resolution gamma spectrometry measurements without preparatory chemical treatment of samples. The overall objective of the present study was to compare 7Be, 210Pb and 137Cs activity concentrations (in Bq/kg) in moss samples collected at two different climate zones: the south of Thailand (7 °N) and in Serbia (∼45 °N) in order to examine deposition of airborne radionuclide in these distant areas. Significant difference of the 210Pb content (almost a factor of 2) in mosses was observed. The mean value of 7Be activity in samples from Serbia was almost 40% higher than activity of those collected in Thailand. Level of 137Cs in Thailand mosses was below the detection limit. It was shown that air transport of water droplets in the area of waterfalls and strong turbulence can deposit U and Th daughter nuclei.