Average Activity Concentrations Of 137Cs Research Articles

137Cs, 40K and 210Po in abiotic components of aquatic ecosystems two rivers in the Can Gio biosphere reserve, Vietnam

Determination of 137Cs, 40K and 210Po in water, bottom sediments and suspended matter of river systems of the Can Gio Biosphere Reserve, Vietnam was carried out. The average activity concentration of 137Cs in waters of Ca Gau and Long Tau was 0.89 ± 0.14 and 1.08 ± 0.15 Bq m−3 and was comparable to the levels of this radioisotope in waters of the East Sea. The activity concentration of 137Cs in bottom sediments was 2.23 ± 0.81 and 3.63 ± 1.24 Bq kg−1. The activity concentration of 137Cs in water and bottom sediments could be characterized as low. So, the water areas of the Ca Gau and Long Tau rivers could be attributed to areas with insignificant pollution by technogenic radionuclides. The 210Ро activity concentration in bottom sediments of the Ca Gau and Long Tau rivers ranged from 9.2 ± 1.2 to 25.5 ± 2.1 Bq kg−1, which is typical for river bottom sediments. Such values indicate the absence of anthropogenic enhancement of the entry of this radionuclide into the Can Gio river systems. The 40K activity concentration varied within 467 ± 42–651 ± 39 Bq kg−1 and represented typical values of potassium content in the bottom sediments of coastal water bodies, subject to a significant influence of the lithogenic component of suspended matter.

On the 30th anniversary of the Chernobyl Nuclear Power Plant Accident, assessment of the activity concentrations and the radiological hazard parameters of soil samples collected from Rize province and districts

Uranium, thorium and potassium are the main terrestrial sources of radiation that are located at different levels in the soil depending on the geographical and geological conditions and contribute to increase of the natural radiation levels of the regions. In addition to the natural radiation sources, Cesium-137 which can spread from nuclear tests and accidents such as Chernobyl Nuclear Power Plant Accident is also an important artificial radiation source of that contributes to the increase of radioactivity in the soil. Determination of both natural and artificial radioactivity levels of soil is important in terms of assessing people's possible exposure to the internal radiation and ensuring that people can be protected from the harmful effects of the external radiation. In this study, on the 30th anniversary of the Chernobyl Nuclear Power Plant Accident, soil samples were collected from Rize province which was affected by the Chernobyl Nuclear Power Plant Accident in 1986 and the activity concentrations of natural and artificial radionuclides were measured and radiological hazard parameters were calculated. Radioactivity measurements were caried out with gamma spectrometry system with a high purity germanium detector. The activity concentrations were measured in range of 4.45 ± 0.39 to 32.19 ± 0.78 Bq kg−1 with an average of 17.68 ± 0.68 Bq kg−1 for 226Ra, 5.58 ± 0.65 to 43.61 ± 1.67 Bq kg−1 with an average of 22.53 ± 1.26 Bq kg−1 for 232Th, 28.82 ± 1.37 to 773.19 ± 12.14 Bq kg−1 with an average of 277.14 ± 6.24 Bq kg−1 for 40K and 1.99 ± 0.17 to 376.85 ± 2.52 Bq kg−1 with an average of 110.11 ± 0.98 Bq kg−1. The average activity concentrations of 226Ra, 232Th and 40K were found below the world median activity concentrations of 35, 30 and 400 Bq kg−1, respectively. Despite the high 137Cs activity concentrations were determined in present study compared to similar works being done in Turkey and other countries, the average activity concentration of 137Cs in investigated samples was significantly found lower than the 137Cs values in soil samples from Rize in 1990 carried out by TAEA. In present study, the average radium equivalent activity (Raeq), external hazard index (Hex) and internal hazard index (Hin) values were below the recommended limits by UNSCEAR. The average absorbed dose rate in air (D) and annual effective dose equivalent (AEDE) values were found lower than the world median values. The calculated excess lifetime cancer risk (ELCR) values for soil samples were obtained less than the precautionary limit of 0.29 × 10−3.

Activity Concentrations of <sup>137</sup>Cs and <sup>90</sup>Sr in Seawaters of East Sea, Korea

Background: This study was a long-term evaluation of 137Cs and 90Sr activity concentrations in seawater samples from the East Sea, Korea, in order to establish current activity levels. Results and long-term monitoring trends will be useful in the future monitoring of environmental radioactivity. Materials and Methods: Surface seawater samples were collected quarterly from Guryongpo and Jangho in the East Coast between 1998 and 2010 and the quarterly deep seawater samples were collected from three sites in the sea adjacent to Ulleung-do between 2012 and 2015. The activity concentrations of 137Cs were measured using a gamma-spectrometer. The activity concentrations of 90Sr and 90Y in a radioactive equilibrium state were measured using a gas flow proportional counter. Results and Discussion: We found the annual average activity concentrations of 137Cs in the surface seawater was 1.66-2.89 mBq∙kg-1 in Guryongpo and 1.68-2.43 mBq∙kg-1 in Jangho. The annual average activity concentrations of 90Sr in the surface seawater was 0.83- 1.98 mBq∙kg-1 in Guryongpo and 0.82-1.57 mBq∙kg-1 in Jangho. The annual average activity concentrations of 137Cs in the deep seawater sites were 1.51-1.73 mBq∙kg-1, 1.19-1.60 mBq∙kg-1 and 0.87-1.15 mBq∙kg-1 in TH, JD, and HP. The annual average activity concentrations of 90Sr in the same deep seawater sites were 1.00-1.94 mBq∙kg-1, 0.82-1.26 mBq∙kg-1, and 0.79-1.32 mBq∙kg-1. The effective half-life was calculated by analyzing change over time in the activity concentration in the surface seawater. The effective half-life of 137Cs was 15.3 ± 0.1 years in Guryongpo and 102 ± 3 years in Jangho. The effective half-life of 90Sr was 28.3 ± 4.3 years in Guryongpo and 16.6 ± 0.1 years in Jangho. The ratio of the average activity concentration (137Cs/90Sr) was 1.72 in the surface seawater, which is similar to the reported ratio of the global radioactive fallout. The ratio in the deep seawater was 1.24, which is somewhat low compared to the global ratio (1.6, 1.8). Conclusion: Activity concentrations of 137Cs and 90Sr in the seawaters of the East Sea were similar to the previously reported activity levels in the East Sea and northwestern Pacific as a result of global radioactive fallout following atmospheric nuclear weapon tests.

Radiocaesium activity concentrations in macrofungi from Galicia (NW Spain): Influence of environmental and genetic factors

Radiocaesium (137Cs) is an artificial radionuclide that can be captured from the soil through the mycelium of fungi. However, in Spain there are few data on its presence in edible mushrooms. 137Cs activity concentrations were determined using 54 samples of wild and cultivated mushrooms and 18 samples of soil, all of them collected in Galicia (NW Spain) during 2010. Samples were analyzed by gamma spectroscopy with a High-Purity Germanium (HPGe) detector. The average activity concentration of 137Cs in wild mushrooms was 249.2Bqkg−1 dry weight (dw) and about 24.9Bqkg−1 fresh weight (fw). Genetic factors (species) influenced the uptake of 137Cs, highlighting Hydnum repandum as the greatest accumulator of all wild species (1016.4Bqkg−1 dw), while cultivated species showed much lower levels (1.6Bqkg−1 fw). Accumulation was also favored by fungal mycorrhizal ecology, whose mycelium was distributed in contaminated soil horizons. The mean levels detected in soils were 14Bqkg−1 fw. Although some species behaved as bioexclusors of radiocaesium, the transfer factors (TF) suggest that mushrooms preferentially bioaccumulate 137Cs. No sample reached the limit of 600Bqkg−1 fw (about 6000Bqkg−1 dw) indicated in the European legislation. In conclusion, the consumption of mushrooms harvested from the investigated areas poses no toxicological risk to human health due to radiocaesium.

Radioactivity concentrations in mussel (Mytilus galloprovincialis) of Turkish Sea coast and contribution of 210Po to the radiation dose

Radionuclides levels were determined in indigenous and transplanted mussels (Mytilus galloprovincialis) collected from Turkish marine environment. Radioactivity concentrations of 137Cs, 40K, 226Ra, 228Ra, 210Po and 210Pb were determined in the soft tissues of the mussel samples collected in Bosphorus Strait, Coasts of Black Sea, Marmara Sea and Aegean Sea. Mussel transplantation was carried out by using mussel cages in Levantine Sea coast since M. galloprovincialis did not naturally adapt along the coast. The average activity concentrations of 137Cs, 40K, 226Ra, 228Ra, 210Po and 210Pb in the coastline of Turkey were found to be 0.7±0.1, 469±24, 0.9±0.1, 1.0±0.1, 122±4 and 10.9±0.9Bqkg−1 in dry weight (dw), respectively. The average of 210Po/210Pb ratio was found to be ∼14. Total annual effective 210Po dose was calculated to be in the range of 0.25–3.30 μSv due to mussel consumption. Radioactivity and dose levels were compared with those of similar studies carried out in Mediterranean countries.

Environmental radioactivity measurements in north–western Greece following the Fukushima nuclear accident

The impact of the Fukushima nuclear accident in north–western Greece was assessed through an environmental monitoring programme activated by the Nuclear Physics Laboratory of the University of Ioannina. Measurements of 131I were carried out in atmospheric particulate, ovine milk and grass samples. In daily aerosol samplings, radioiodine was first detected on March 25–26, 2011 and reached maximum levels, up to 294 μBq m−3, between April 2 and April 4, 2011. In ovine milk samples, 131I concentrations ranged from 2.0 to 2.7 Bq L−1 between April 2 and April 6, 2011, while an average activity of 2.7 Bq kg−1 was measured in grass samples on April 4, 2011. The 134,137Cs isotopes were below detection limits in all samples and could only be determined in the air, by analysis of multiple daily filters. A maximum average activity concentration of 137Cs amounting to 24 μBq m−3 was measured during the period from April 5 to April 9, 2011, with the 134Cs/137Cs activity ratio being close to unity. Activity concentrations were consistent with measurements conducted in other parts of the country and were well below those reported in May 1986 after the Chernobyl accident. The committed effective dose to the whole body and to the thyroid gland from inhalation of 131I was estimated for the adult and infant population and was found to be of no concern for the public health.

Transport and distribution of artificial gamma-emitting radionuclides in the River Yenisei and its sediment

Discharges from the Krasnoyarsk Mining and Chemical Industrial Complex (KMCIC) near Krasnoyarsk resulted in radioactive contamination of sediments of the River Yenisei. Between 1999 and 2006, 16 sediment cores were collected at different positions 15–1500 km downstream from the discharge point. The concentration of artificial gamma-emitting radionuclides ( 137Cs, 60Co, 152Eu, and 241Am) was determined with the objective to analyze the migration processes leading to the transport of these radionuclides along the river and to their vertical distribution within the sediment. In cores taken in the vicinity of the reactors, the average activity concentration of 137Cs, 152Eu, and 60Co was about 1000 Bq kg −1, and the activity concentration of 241Am was about 20 Bq kg −1. Contamination levels of artificial radionuclides were decreasing with increasing distance downstream the KMCIC: The fastest decrease of average activity by a factor of 10 over a distance of 300 km was observed for 241Am, whereas for 137Cs this decrease occurred over a distance of 1100 km. Sequential extraction experiments revealed that in all depths and at all distances the studied radionuclides were tightly bound to the sediment. To investigate the mechanisms of transport of the 137Cs and 60Co contamination, mathematical models have been used to describe the contamination in the river water and within the sediments.

Radioactivity concentrations and dose assessment in surface soil samples from east and south of Marmara region, Turkey

The activity concentrations of 137Cs, 40K, 232Th, 238U and 226Ra were measured in surface soil samples from East and South of Marmara region, Turkey. The physico-chemical parameters (organic matter, CaCO3 contents and pH-value) of the soil samples were determined in the samples collected from 100 sampling stations. The average activity concentrations of 137Cs, 40K, 232Th, 238U and 226Ra were found to be 27.46+/-21.84, 442.51+/-189.85, 26.63+/-15.90, 21.77+/-12.08 and 22.45+/-13.31 Bq kg(-1), respectively. The mean value of total annual external gamma radiation dose equivalent for the natural radionuclides was calculated to be 54.86 microSv. The current data were compared with those found in the other locations of Turkey and different countries.

Contamination of the southern Baltic Sea with 137Cs and 90Sr over the period 2000–2004

Changes of the 137Cs activity concentrations in the southern Baltic Sea waters were investigated over the period 2000–2004 and distribution of the 90Sr concentrations was determined in 2004. In the discriminated period further decrease of 137Cs concentrations was observed. The average activity concentration of 137Cs declined from 59.4 Bq/m 3 in 2000 to 45.1 Bq/m 3 in 2004. The greatest changes of 137Cs activities occurred in 2003 as a consequence of the medium-size inflow of a saline waters from the North Sea. This inflow affected 137Cs activities as well as its distribution in the Baltic Sea. Changes in 90Sr activity concentrations proceeded at much slower rate. The average activity concentration of 90Sr was equal to 8.7 Bq/m 3 in 2004. The annual fluvial 137Cs fluxes from the Vistula river were also estimated. In 2000, the 137Cs load from Vistula was of an order of 0.15 TBq/year, and in 2004 0.05 TBq/year.

Activity levels of 137Cs and 40K in the skin and the cutaneous organs of a cow.

We have performed an extensive study to determine the activity distributions of radiocesium (137Cs) and of the radioisotope 40K of potassium in the whole body of a cow. ICRP assumes that cesium and potassium are distributed homogeneously throughout the whole body of an organism. The current investigation measured concentrations of 137Cs and 40K in components of the skin, horns, and hooves of a cow. Activity levels of 137Cs were caused by the long-term ingestion following the Chernobyl fallout, whereas the naturally occurring potassium (40K) is an essential part of cow's normal diet. The cow was born at the time of the fallout following the Chernobyl accident and had ingested heavily contaminated forage during its entire lifetime. Activities of 137Cs and 40K were determined simultaneously by gamma spectrometry. All activities are related to the day of slaughter and include also corrections for self attenuation of photons caused by the different densities of the samples. Radionuclide concentrations in samples were corrected for moisture losses incurred during freezing and sample preparation. Surface contamination on the skin was estimated by rinsing it in heated water followed by removal of the epidermis and hair. In comparison with the activities of the components of the skin we observed a considerable amount of external contamination on the surface of the skin. But with respect to whole body countings of the animal this amount of external contamination appears to be negligible. It was found that activity ratios of 137Cs to 40K are greater than 1 in all measured components. The average activity concentrations of 137Cs and 40K in the common integument are 23.3 Bq kg(-1) and 13.3 Bq kg(-1), respectively. The highest activity concentrations of 137Cs and 40K were measured in clean hair and hypodermis. Despite being its largest organ, the cow's skin contains probably less than 1% of the animal's whole body 137Cs activity.

Body burden and distribution of 137Cs in reindeer

The whole body was collected from 6 reindeer that had been grazing contaminated pasture and from 6 reindeer that had been fed uncontaminated feed the last weeks before slaughter. The body was emptied from in-gesta and weighed. Samples were taken from skeletal muscle, kidneys, heart, liver, lungs, rumen wall, bone and blood. The total activity of 137Cs in the ingesta-free body and the acitivity concentration of l37Cs in the different tissues were determined. The highest acitivity concentrations of l37Cs were found in skeletal muscle and in kidneys. Activity concentrations in kidneys, heart, liver, lungs and rumen wall, relative to skeletal muscle, were lower in reindeer with decreasing radiocaesium levels, compared to reindeer with continuous intake of radiocaesium, indicating a more rapid elimination in these tissues than in muscle. The ratios between average activity concentration of 137Cs in whole body and acitivity concentration in muscle from the same animal, ranged from 0.51 to 0.62. A factor of 0.57 is suggested for calculating average body activity concentration of radiocaesium from known activity concentration in muscle.

Statistical characteristics of the activity concentration in the surface layer of the atmosphere in the 30 km zone of Chernobyl

Series of measurements of the daily average activity concentrations of 137Cs and 144Ce in the atmospheric surface boundary layer in the 30 km zone around the Chernobyl Nuclear Power Plant are discussed with regard to their statistical characteristics. A high level of fluctuation in the specific activity concentration was found with maxima exceeding the annual average by a factor of 10–20 and lasting up to 14 days. During the years 1987–1991 the absolute values of the fluctuations decreased with time. The decrease of the activity concentrations was found to be higher than that due to radioactive decay alone.

Estimate of the Dose Due to 90Sr to the Austrian Population After the Chernobyl Accident

In order to estimate the contribution of 90Sr to the exposure of the Austrian population, the ratio of 90Sr to 137Cs in 126 food samples and nine drinking water samples was determined. From this and the average activity concentration of 137Cs in each type of food as obtained by the measurement of some 100,000 food samples after the Chernobyl accident, a good estimate of the average activity concentration of 90Sr in these food items could be obtained. Samples were investigated at various times after the accident to take into account possible changes with time in the 90Sr-activity concentration and its ratio to 137Cs. Also, pre-Chernobyl samples were measured to estimate the relative contribution of the reactor accident and the fallout of the atomic bomb testing to the intake of 90Sr. Assuming average food consumption, the intake of 90Sr for an adult person amounted to 168 Bq in the first year and 115 Bq in the second year after the accident, resulting in an effective dose equivalent of 5.9 muSv and 4.0 muSv, respectively. This is a minor fraction of the dose due to the ingestion of Cs isotopes, which amounted to 360 muSv in the first year and 97 muSv in the second year. For the one-year-old infant, a 90Sr intake of 96 Bq (10.5 muSv) in the first year and 65 Bq (7.1 muSv) in the second year is estimated. Approximately 50% of the intake in the first year and 70% of that in the second year are due to 90Sr from nuclear weapons testing.