Determination of131I,134Cs,137Cs in plants and cheese after Chernobyl accident in Roumania

Various samples from the south-east region of Roumania/greens, fodder, cheese/were analyzed for¹³¹I,¹³⁴Cs and¹³⁷Cs concentrations in May and July 1986 by -ray spectrometry. The concentrations are reported in nCi. kg^–1 wet weight. For greens, a considerable decrease was observed for¹³¹I/to 3.0–7.0 nCi. kg^–1/,¹³⁴Cs/to 0.5–2.0 nCi.kg^–1/ and¹³⁷Cs /to 1.0–4.0 nCi. kg^–1/ from the first half /5–15 May/ till the end of May 1986. For cheese, maximum values were measured between 5 and 15 May /sheep cottage cheese: 500–800 nCi.kg^–1 for¹³¹I, 25–50 nCi. kg^–1 for¹³⁴Cs, 40–80 nCi. kg^–1 for¹³⁷Cs/; at the beginning of July a considerable decrease /to 5–10 nCi. kg^–1 for¹³¹I, 1.2–2.0 nCi.kg^–1 for¹³⁴Cs, 2.2–3.0 nCi. kg^–1 for¹³⁷Cs/ was observed. In autumn 1986 a small increase up to 2.0–3.0 nCi. kg^–1 for¹³⁴Cs and 3.4–5.0 nCi. kg^–1 for¹³⁷Cs /in November/ was reported. The population's internal possible contamination was strongly limited by the authorities' severe control of the food-stuff.     

Determination of131I,134Cs,137Cs in grass and cheese after Chernobyl accident in Austria

Various samples from Styria /grass/ and Salzburg /cheese/ were analyzed for¹³¹I,¹³⁴Cs and¹³⁷Cs concentration during April–July 1986 by -ray spectrometry. The concentrations are reported in nCi kg^–1 wet weight. The concentration values found for¹³¹I 0.2–17.2 nCi kg^–1 /grass/, 0.1–0.5 nCi kg^–1 /cheese/, for¹³⁴Cs 1.1–6.2 nCi kg^–1 /grass/, 0.2–1.3 nCi kg^–1 /cheese/, for¹³⁷Cs 1.6–15.7 nCi kg^–1 /grass/, 0.3–2.2 nCi kg^–1 /cheese/. While radioactivity of¹³¹I,¹³⁴Cs and¹³⁷Cs in cheese samples increases from May to June, it decreases in grass samples from May to July 1986.     

Determination of137Cs and134Cs radioisotopes in various mushrooms from Austria one year after the Chernobyl incident

Many mushrooms from Austria collected between May 25 and September 21, 1987 were analyzed for¹³⁷Cs and¹³⁴Cs by -spectroscopy one year after the reactor accident at Chernobyl. The following concentrations /nCi kg^–1 wet weight/ were found:¹³⁷Cs 0.4–43.2 nCi kg^–1,¹³⁴Cs 0.1–16.4 nCi kg^–1. The concentration of cesium isotopes in Cantharellus cibarius /Klagenfurt/ and Xerocomus badius /Upper-Austria, Mühlviertel/ were considerably higher than the tolerance level /5 nCi kg^–1/.     

Accumulation of103Ru,137Cs and134Cs in fruitbodies of various mushrooms from Austria after the Chernobyl incident

Various mushrooms from Austria were analyzed for¹⁰³Ru,¹³⁷Cs and¹³⁴Cs after the reactor accident at Chernobyl /19.6.–26.10. 1986/ by -spectroscopy. The following concentration (nCi/kg wet weight) values were found:¹⁰³Ru 0.1–4 nCi/kg,¹³⁷Cs 0.5–104 nCi/kg,¹³⁴Cs 0.3–42 nCi/kg. The concentration of cesium isotopes in Cantharellus cibarius /lower Austria/, Leccinum scabrum /lower Austria/ and Xevocomus badius /lower Austria/ was considerably higher than in other mushroom samples.     

Radionuclide concentration in sewage sludge at several location in Austria after the Chernobyl accident

The concentration of the radionuclides¹⁰³Ru,¹³⁴Cs and¹³⁷Cs in sewage sludge samples which were collected between July and September 1986, were measured by -ray spectrometry. High concentration of¹⁰³Ru,¹³⁴Cs and¹³⁷Cs were found in sewage sludge samples from Lower-Austria /Scheibbs, Zwettl/ and Styria /Eisenerz, Leoben/. the radioactivity concentration of¹³⁷Cs was two times higher than that of¹³⁴Cs. Following concentration values were found:¹⁰³Ru 0.1–63.0 nCi kg^–1,¹³⁴Cs 0.3–41.6 nCi kg^–1, and¹³⁷Cs 0.3–83.3 nCi kg^–1. The activity of these nuclides decreased from July 1986 to September 1986.     

Determination of137Cs and134Cs in air samples collected near Belgrade /Yugoslavia/ following the Chernobyl accident

This paper presents the results of measurements of¹³⁷Cs and¹³⁴Cs content in air sampled during May 1986. Maximum concentrations:¹³⁷Cs 2.94±0.01 Bq m^–3 and¹³⁴Cs 1.38±0.01 Bq m^–3 were registered on May 3. Several other long lived radionuclides having -energies in the region 33 keV to 1365 keV were registered in the same samples two years later. The results of measurements of the total -activity in air for the same period are also presented.     

Activities evolution of Chernobyl103Ru,134Cs and137Cs in Cluj fallout

The evolution of Chernobyl¹⁰³Ru,¹³⁴Cs and¹³⁷Cs in accumulated fallout is rigorously followed. The¹⁰³Ru activity of about 12 kBq.m^–2 in the middle of May 1986 became insignificant at the end of 1986, while the levels of¹³⁴Cs and¹³⁷Cs have changed during 3 years from 2.5 kBq.m^–2, respectively, 5 kBq.m^–2 to about 0.9 kBq.m^–2, respectively 4.7 kBq.m^–2 according to their proper half-lives.     

Distribution of 131I, 134Cs, 137Cs and 239,240Pu concentrations in Korean rainwater after the Fukushima nuclear power plant accident

Radionuclides such as ¹³¹I, ¹³⁴Cs, ¹³⁷Cs, and ^239,240Pu in Korean rainwater have been analyzed by Korea Research Institute of Standards and Science (KRISS) since the Fukushima nuclear power plant accident in March 2011 to investigate the activity level, distribution pattern, and temporal variation and to assess the radiation dose the public is exposed to. The concentration of ¹³¹I in the Korean rainwater samples varied between 0.033 (minimum detectable activity; MDA) and 1.30 Bq kg^?1 and the concentrations tended to decrease exponentially with time. The concentrations of ¹³⁴Cs and ¹³⁷Cs in rainwater ranged from 0.01 to 334 ± 74 and 0.29 ± 0.01 to 276 ± 1 mBq kg^?1, respectively. The mean activity ratio of ¹³⁷Cs/¹³⁴Cs in the rainwater samples collected from April 18 to May 12 was estimated to be 0.44 ± 0.21, and this value is lower than that (ca. 1) observed in Fukushima, Japan, when there was an escape from the nuclear reactors. When an attempt was made to analyze Pu isotopes in rainwater samples, no Pu isotopes were detected above the MDA in any of the rainwater samples. Although the locations investigated were different from Asia to Europe, the concentrations of ¹³¹I, ¹³⁴Cs and ¹³⁷Cs in the rainwater are comparable, which suggests a global contamination of ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs occurred because of the Fukushima nuclear power plant accident.     

A simple preparation of calibration curve standards of134Cs and137Cs by serial dilution of a standard reference material

Two sets of calibration standards for¹³⁴Cs and¹³⁷Cs were prepared by small serial dilution of a natural matrix standard reference material, IAEA-154 whey powder. The first set was intended to screen imported milk powders which were suspected to be contaminated with¹³⁴Cs and¹³⁷Cs. Therefore the concentration range of the calibration standards were about 40–400 Bq/kg. The precision of the preparation of the standard with about 7 Bq/kg of¹³⁴Cs and 39 Bq/kg of¹³⁷Cs at measurement time was 7.4% and 3.2%, respectively. The preparation of a similar standard by spiking the matrix with radioisotope solutions resulted in a poorer precision, about double that of the former technique. The other set of calibration standards was prepared to measure the environmental levels of¹³⁷Cs in commercial Venezuelan milk powders. Their concentration ranged from 3–10 Bq/kg of¹³⁷Cs. The accuracy of these calibration curves was checked by using IAEA-152 and A-14 milk powders. Their measured values were in good agreement with their certified values. Finally, it is shown that these preparation techniques by serial dilution of a standard reference material were simple, rapid, precise, accurate and cost-effective.This work was partly funded by a research contract PC-075 from the Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICIT).     

Radiocesium concentration in milk after the Chernobyl accident in Japan

Radiocesium concentrations in cow's milk from two producing districts in Japan were measured monthly for three years following the Chernobyl accident. The Chernobyl contribution in¹³⁷Cs concentration was evaluated from the¹³⁴Cs concentration and the¹³⁷Cs/¹³⁴Cs ratio. The highest¹³⁷Cs concentration of 0.6 Bq l^–1 was observed in May 1986 and the Chernobyl contribution has decreased during three years to levels corresponding to the contribution from past nuclear weapons fallout. Annual values of child internal dose through milk consumption were estimated at 0.6, 0.3 and 0.1 Sv for the first, the second and the third year following the accident, respectively.     

Determination of40K and137Cs concentration in selected honey samples

Seventeen honey samples collected at different sites during 1992 have been measured using the method of -spectroscopy. Measurements were performed by a low background high purity germanium spectrometer of a relative efficiency of 14.5% and an energy resolution of 1.7 keV. Using natural -ray sources to determine efficiency, it has been shown that out of 17 samples of natural honey only two (of meadow type) have specific activity of¹³⁷Cs greater than 0.5 Bq kg^–1. The remaining samples have the same¹³⁷Cs concentrations as before May, 1986. Predominant activity in all samples comes from the⁴⁰K radionuclide, indicating natural honey.     

Depth distribution of239,240Pu and137Cs in soils of South Korea

Depth distribution of^239,240Pu and¹³⁷Cs in the soils of South Korea have been studied. The average accumulated depositions were estimated roughly to be 54.8±32.1 Bq·m^–2 for^239,240Pu, 1.6±1.0 Bq· ·m^–2 for²³⁸Pu and 1982.8±929.1 Bq·m^–2 for¹³⁷Cs. The activity ratios of^239,240Pu/¹³⁷Cs in soils were found to be in the narrow range of 0.0153 to 0.0364 with a mean value of 0.0230±0.006. The concentrations of^239,240Pu and¹³⁷Cs in soils decrease exponentially with increasing the soil depth. A significant correlation was found between the concentration of^239,240Pu and that of¹³⁷Cs. The activity ratios of^239,240Pu/¹³⁷Cs tend to increase slightly with increasing soil depth.     

Distribution of137Cs and228Ra in the sediments of Aswan High Dam lake

Sediment samples of the High Dam lake were investigated for their¹³⁷Cs,²²⁶Ra,²²⁸Th, and⁴⁰K content, using low-level -spectroscopy. The results show that at the begining of the lake (500 km from the High Dam), where sediments consist mostly of sand, the level of¹³⁷Cs is very low (0.1 Bq kg^–1). The maximum value (22.3 Bq kg^–1) was found 40 km from the wall of the High Dam, where the composition of the sediments is nearly 50% clays. The distribution of the natural nuclides²²⁶Ra,²²⁸Th, and⁴⁰K shows a different trend.     

Deposition of gamma-emitting nuclides in Japan after the reactor-IV accident at Chernobyl'

The wet and dry deposition of gamma-emitting nuclides are presented for Tsukuba and eleven stations in Japan following the nuclear reactor accident at Chernobyl'. In Japan fallout from the reactor at Chernobyl' was first detected on May 3, 1986, a week after the accident. Abruptly high radioactive deposition, which mainly consists of¹³¹I,¹³²I,¹⁰³Ru,¹³⁷Cs and¹³⁴Cs, was observed in early May. The cumulative amount of¹³¹I,¹⁰³Ru and¹³⁷Cs in May at Tsukuba were 5854±838 Bq·m^–2, 364±54 Bq·m^–2 and 130±26 Bq·m^–2 (decay was corrected to April 26), respectively. The monthly¹³⁷Cs deposition in May corresponds to 2.5% of the cumulative¹³⁷Cs deposition during the period from 1960 through 1982. Most of the Chernobyl' radioactivities, especially¹³¹I, are scavenged from the atmosphere by the wet removal process.     

Extraction-chromatographic separation of137mBa from137Cs

The possibilities of extraction-chromatographic separation of^137mBa from¹³⁷Cs in genetic succession were studied, using columns filled with support beads loaded with the extractant H⁺[)–(3)–1,2–B₉C₂H₁₁]₂Co^–, further referred to as dicarbolide-H⁺, in nitrobenzene. The dependence of the amount of separable activities on experimental conditions was established. Optimal conditions were selected for the separation process. The effects of isotopic and nonisotopic carriers of^137mBa on the separation and the degree on saturation of extraction-chromatographic column with Ba²⁺ ions were evaluated. The effects of acidity of the elution solutions, of flow-through velocity, the amount of elution solution and the quality of carrier beads on the separation process were assessed. The extraction-chromatographic yield was calculated and the number of possible repeated elution cycles for^137mBa with saline and some other eluents was determined.     

The biological half-life of137Cs in snails

The biological half-life of¹³⁷Cs in snails Helix pomatia after a single administration of contaminated diet has been investigated. The calculation was based on the retention of¹³⁷Cs in snails in vivo. It was found that loss of cesium from snails can be explained by a two-exponential retention curve leading to biological loss constants _{B 1}=0.27 d^–1 and _{B 2}=0.024 d^–1, which correspond to biological half-lives of T_{B 1}=2.5 d and T_{B 2}=28.5 d respectively. The equation describing the retention of¹³⁷Cs in snails is also presented.     

Distribution of137Cs,40K,238U and232Th in soils from Northern Venezuela

More than one hundred undisturbed soil samples from Northern Venezuela and the islands of Margarita and Los Roques have been analyzed for¹³⁷Cs,⁴⁰K,²³⁸U and²³²Th by -ray spectroscopy. The specimens were taken from between 5–10 cm below the earth's surface. Thus, they are valid not only for the¹³⁷Cs deposition studies but also for the estimation of the natural -ray dose from primordial radionuclides that form the terrestrial component. The concentration of⁴⁰K was directly determined from its 1461 keV -ray, while those of¹³⁷Cs,²³⁸U and²³²Th were performed using a -ray from one of their daughter radionuclides: the 661 keV -ray of^137mBa for¹³⁷Cs, the 1760 keV -ray of²¹⁴Bi for²³⁸U and the 2620 keV -ray of²⁰⁸Tl for²³²Th. Finally, the concentration values were compared with those of global estimates.     

Modes of137Cs desorption from marine sediments by sea water

Sea water is observed to be a good desorbing agent for¹³⁷Cs from marine sediments. Investigations on the sites of¹³⁷Cs binding and their abundance by desorption over extended periods indicated that, whatever the time of contact of sorption,¹³⁷Cs has three modes of desorption: fast component with desorption half-time of 30–50 min, medium component with desorption half-time of 25–50 h and slow component with desorption half-time of 31–112 days. These are expected to be sites of ion exchange, slower exchange and trapped Cs in the clay mineral layer lattices.     

Uptake of134Cs by plants from three different types of soil

In¹³⁴Cs uptake by the roots of orchard grass and beans planted in three different lands of soil has been studied. For this purpose, a¹³⁴Cs radionuclide solution having 0.3086 Ci/pot radioactivity was added to Ando, Serpentine and Alluial and Clay soil which were fertilized by Standard, –K, +Ca, Water limited and Control for both orchard grass and bean groups. Thus, the above mentioned groups have been harvested and left to dry. The contamination levels these plants have been detected and measured by using an HPGe detector interactively working with MCA. Finally, it has been determined that the¹³⁴Cs uptakes depend primarily on soil characteristics. Besides the decrease in the¹³⁴Cs activity for the plants grown in soils to which the stable cesium or potassium was added 0.011–1.38 per cent activity for the root of plants grown in free K soils was observed. Moreover, highest¹³⁴Cs activity has been determined for the plants grown in –K fertilized soil with respect to the other soil samples.     

90Sr and137Cs in atmospheric precipitations during 1980–1985 in the Bucharest area

Samples of precipitations were collected quarterly and analyzed for⁹⁰Sr and¹³⁷Cs. The values obtained ranged from 0.001 to 0.004 Bq dm^–3, with a maximum of 0.010 Bq dm^–3 for⁹⁰Sr;¹³⁷Cs values ranged from 0.001 to 0.005 Bq dm^–3, with a maximum of 0.070 Bq dm^–3. The highest values were observed during the 2nd and 3rd quarters of 1981.