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.     

131I,134Cs and137Cs concentrations in 1986 for some Roumanian foodstuffs

Results of post-Chernobyl measurement on some foodstuff samples /eggs, meat, fruit, honey, medicinal herbs/ from South-Eastern Roumania are presented. Gamma-ray spectrometry was used; the radioactive concentration values are given in nCi.kg^–1 wet weight. A strong decrease in concentrations for eggs from 6–7 May /3.0–7.4 nCi for¹³¹I, 0.25–0.40 nCi for¹³⁴Cs, 0.40–0.85 nCi for¹³⁷Cs per one egg, mainly in the yolk/ to 19–25 May /0.3–1.0 nCi for¹³¹I, 0.15–0.25 nCi for¹³⁴Cs, 0.25–0.40 nCi for¹³⁷Cs/ was observed. The mean values for lamb meat /joint muscle/ were 500 nCi.kg^–1 for¹³¹I, 12 nCi.kg^–1 for¹³⁴Cs, 22 nCi.kg^–1 for¹³⁷Cs /18–25 May/. Relatively reduced values were found for fruits, e.g. compared to dairy products¹. In May–June 1986, the food consumption in Roumania was strictly limited and controlled by competent authorities.     

Elevated rice 137Cs concentrations near the water inlet in paddy fields after the Fukushima nuclear accident

Journal of Radioanalytical and Nuclear Chemistry - The reasons why rice 137Cs concentrations increase near the water inlet were investigated using rectangular experimental plots settled in paddy...     

Distribution of3H,137Cs and239,240Pu in the surface seawater around Korea

The concentrations of³H,¹³⁷Cs and^239,240Pu were determined in surface seawaters collected at 21 sampling stations around Korea from October of 1994 to May of 1995. The results were consistent with the past data observed in the North Pacific. The concentrations of³H and¹³⁷Cs did not show much difference no matter where the samples were taken. Due to the limited distribution of sampling points, no systematic change in³H and¹³⁷Cs levels with latitude was observed. On the other hand,^239,240Pu concentration in the East Sea (Japan Sea) was somewhat higher than that in the South and the Yellow Seas, although the data on^239,240Pu concentration were not enough to explain the reason. The activity ratios of^239,240Pu/¹³⁷Cs in surface seawater ranged from 0.13% to 0.44% with a mean of 0.25±0.08%. The activity ratios were lower than those of the global fall-out level, 1.1%. This result presumably arose from the different behavior of the two radionuclides in seawater.     

Distribution of137Cs and239,240Pu in the sediment of the Seto Inland Sea

The contents and distribution patterns of¹³⁷Cs and^239,240Pu in the sediments of the Seto Inland Sea were determined. In most of the sediment columns, approximately uniform concentrations were found to a depth of around 20 cm, probably due to bioturbation. Total amounts of¹³⁷Cs in the sediment column are considerably lower than the global fallout inputs. It is suggested that a significant portion of¹³⁷Cs input was removed from the Seto Inland Sea to the open ocean. Large excess inventories of^239,240Pu over fallout input were observed in the investigated sediment columns.     

131I and137Cs in the environment following the chernobyl reactor accident

The measured¹³¹I and¹³⁷Cs radioactivity in air, on the ground, and in milk at different places throughout the world were compared. It was found that the measured radioactivity can be explained assuming that the radioactive material released during the Chernobyl accident was transported primarily in two segments. The first part was transported at low altitudes, contaminated areas around Chernobyl and extended up to 2000–3000 km. The second part was injected into the troposphere. The radionuclides carried at high altitudes by the west-to-east winds traveled over continental Asia, Japan, Pacific Ocean, and North America. The time integrated radioactivity concentrations in nearground air particulates, the integral ground deposition densities and milk concentrations can be described by an exponential decrease as a function of the distance from Chernobyl. The intercept (values near the damaged reactor) and the slopes (describing dispersion conditions) were calculated. The deposition velocities for¹³¹I and¹³⁷Cs transported with the two altitude air masses are given.This work was supported in part by the Computer Center of the University of Maryland.     

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.     

239,240Pu,241Am and137Cs in soils from several areas in China

This paper gives the first data on^239,240Pu and²⁴¹Am in Chinese soils. Surface soil samples with a set of 0–5 cm and 5–20 cm depth were collected from Beijing, Taiyuan, Shijiazhuang and Jinang of China in 1990, and^239,240Pu,²⁴¹Am and¹³⁷Cs, including naturally occurring radionuclides, in these samples were measured to evaluate their present levels and distributions. From these results, the average accumulated depositions were estimated roughly to be 24±13 MBq/km² for^239,240Pu, 10±5 MBq/km² for²⁴¹Am and 1.2±0.7 GBq/km² for¹³⁷Cs. The activity ratios of^239,240Pu/¹³⁷Cs and²⁴¹Am/^239,240Pu ranged from 0.016 to 0.026 with a mean value of 0.020±0.004 and 0.35 to 0.49 with a mean value of 0.43±0.05, respectively.     

On peculiarities of vertical distribution of 239,240Pu, 238Pu and 137Cs activity concentrations and their ratios in lake sediments and soils

Distributions of ^239,240Pu, ²³⁸Pu and ¹³⁷Cs activity concentrations in the cores of sediments in the shallow lake, flooded and upland forest soils taken in the vicinity of Vilnius city were analyzed. The radiochemical, α-spectrometric and mass spectrometric methods were used for the plutonium evaluation and γ-spectrometry was used for the radiocesium evaluation. The only peak of enhanced radionuclide activity concentrations was determined for the lake bottom sediments, whereas vertical profiles of the radionuclide activity concentrations in flooded and upland forest soil cores were distinguished by two peaks. The obtained values of the activity concentration ratio ²³⁸Pu/^239,240Pu and the isotopic ratio ²⁴⁰Pu/²³⁹Pu indicated that the global fallout was a source of plutonium in the investigated environment. Chernobyl-derived radiocesium was detected solely in the surface layers (2–11 cm) of the studied sample cores. The contribution of the Chernobyl deposits amounted to about 2.26, 6.11 and 20.9 % of the total radiocesium inventory in the bottom sediments, the upland soil and flooded soil, respectively.     

Study of 137Cs, 90Sr, 239,240Pu, 238Pu and 241Am behavior in the Chernobyl soil

The vertical distribution of ¹³⁷Cs, ⁹⁰Sr, ^239,240Pu, ²³⁸Pu and ²⁴¹Am was determined in soil samples collected from the Chernobyl exclusion zone in 1994. The results show very close distribution profiles for all radionuclides, with about 90% of the total activity of each nuclide lying between the surface and the fourth centimeter. Sequential extraction methods were used to determine the association of radionuclides in soil. The data on vertical distribution of radionuclide species were used to calculate their vertical migration parameters.     

Geochemical association of137Cs and239,240Pu in the oligotrophic and mesotrophic lake sediments

Geochemical association of¹³⁷Cs and^239,240Pu in the surface sediments from two oligotrophic and mesotrophic lakes in Japan was studied by sequential chemical extractions. The fractions separated were exchangeable and bound to carbonate, bound to oxides, bound to organic mattersulfides, and residual. The¹³⁷Cs and^239,240Pu were mainly associated with the organic matter-sulfides and residual fractions but exhibited the different vertical profiles at both lakes. The differences in association patterns between the lakes may be controlled by transport of these nuclides by organic settling particles to the bottom sediments and decomposition of the organics in the sediments.     

Distribution of 137Cs and 134Cs in the North Pacific Ocean: impacts of the TEPCO Fukushima-Daiichi NPP accident

Impact of the TEPCO Fukushima-Daiichi NPP accident, FNPP1, to the North Pacific Ocean occurred through two pathways, namely direct release and atmospheric deposition to wide ocean surface. We collected more than 100 seawater samples in the North Pacific Ocean in April and May 2011 by seven commercial ships as VOS. Since the sample volume was 2 l each, we measured radiocaesium activity at Ogoya Underground Facility to obtain reliable activity. ¹³⁷Cs was detected at all stations and ¹³⁴Cs was detected at most of the stations in the North Pacific Ocean. The ¹³⁷Cs activity ranged from around 1 to 1,000 Bq m^?3 with activity ratios of ¹³⁴Cs/¹³⁷Cs close to 1 which is a signature of radiocaesium originated from the FNPP1 accident. At east of the International Date Line north of 40°N in the Pacific Ocean in April 2011, the ¹³⁴Cs activity ranged from 2 to 12 Bq m^?3.     

The reducing rate of radiocesium 137Cs in the North Pacific surface water after the TEPCO fukushima Dai-ichi nuclear power plant accident

Journal of Radioanalytical and Nuclear Chemistry - We started monitoring the radiocesium released from Fukushima in the North Pacific surface water from May 2011 after the accident soon to June...     

Low 137Cs retention capability of organic layers in Japanese forest ecosystems affected by the Fukushima nuclear accident

Journal of Radioanalytical and Nuclear Chemistry - Quantitative understanding of 137Cs retention behavior in organic layers in Japanese forest ecosystems is of primary importance in the assessment...