Influence of nuclear reactor accident at Chernobyl' on the environmental radioactivity in Toyama

The environmental radioactivity caused by the reactor accident at Chernobyl' was investigated from May 7 to May 31 of 1986 in Toyama. Measurement of radioactivities in airborne particles, rain water, drinking water, milk, and mugwort are carried out by gamma-ray spectrometry (pure Ge detector; ORTEC GMX-23195). Ten different nuclides (103Ru, 106Ru, 131I, 132Te-I, 134Cs, 136Cs, 137Cs, 140Ba-La) are identified from samples of airborne particles. In the air samples, a maximum radioactivity concentration of each nuclide is observed on 13th May 1986. The time of the reactor shut-down and the flux of thermal neutron at the reactor were calculated from 131I/132I and 137Cs/134Cs ratio. The exposure dose in Toyama by this accident is given as follows: internal exposure; [thyroid] adult-59 microSv, child-140 microSv, baby-130 microSv, [total body] adult-0.2 microSv, child, baby-0.4 microSv, external exposure; 7 microSv, effective dose equivalent; adult-9 microSv, child-12 Sv, baby-11 microSv.     

Chemical fraction of radiactive cesium in atmospheric aerosol in Prague after the Chernobyl accident

Aerosol filters exposed during the period of direct contamination after the NPP accident at Chernobyl have been analyzed with the aim to determine the physicochemical forms of¹³⁷Cs. A modified sequential analysis of solubility according to Tessier was used. It was shown that the content of water-soluble radiocesium fraction (about 45%) was substantially lower when compared with the analysis results of aerosols collected in the U.K. Another marked difference was found in the case of undissolved residue, where, on the contrary, the¹³⁷Cs content was higher. No significant differences were found in the composition of samples collected during the time period of, May 1–May 6, 1986. In a sample collected in a later period a lower percentage of water soluble¹³⁷Cs fraction and a higher percentage of¹³⁷Cs in the undissolved residue was found.     

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.     

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.     

Chernobyl radioactivity on the Black Sea coast of Turkey

After the Chernobyl reactor accident, Eastern Black Sea coast was one of the heavily contaminated regions of Turkey. Clouds loaded with radioactive isotopes arrived the region on May 1986 and emptied their contents with the heavy rains that are frequently seen in the region. In order to asses the current level of contamination, several different samples, moss, lichen, litter, surface soil and soil cores were collected on August 1994. Samples were brought to the laboratory and their moisture, pH and organic matter contents were determined. Gamma-ray spectra of the samples were collected with a HpGe detector. (137)Cs was the major isotope observed. Activity of most litter samples were below 1000 Bq/kg, while most of the moss samples had activities below 5000 Bq/kg, there were a few with higher (137)Cs activities. Surface soil samples generally had activities less than 2000 Bq/kg and depth profiles of cesium activities in the soil cores showed regional variations.     

The reactor accident at Chernobyl': identification of radionuclides in fallout in Niigata City

The fallout caused by the accident of Chernobyl' nuclear reactor has been monitored in Niigata City (April 30-June 3, 1986). Twelve nuclides (131I, 132I, 129Te, 129mTe, 132Te, 134Cs, 136Cs, 137Cs, 103Ru, 99mTc, 140La, 140Ba) were identified in aerosol samples. The same nuclides plus 7Be were identified in rain-water. Gaseous and particle-bound 131I were separately trapped on a glass filter and a charcoal filter, respectively. Results indicate 50-60% of atmospheric 131I is gaseous and the rest is particle-bound. Chloroform extraction of rain-water revealed that 40-60% of 131I in the rain-water sample exists in the form of IO3- and 131IO3- (131IO4-)/131I- seemed to increase with the lapse of time after the accident.     

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.     

Chernobyl radioactivity on the Black Sea coast of Turkey

After the Chernobyl reactor accident, Eastern Black Sea coast was one of the heavily contaminated regions of Turkey. Clouds loaded with radioactive isotopes arrived the region on May 1986 and emptied their contents with the heavy rains that are frequently seen in the region. In order to asses the current level of contamination, several different samples, moss, lichen, litter, surface soil and soil cores were collected on August 1994. Samples were brought to the laboratory and their moisture, pH and organic matter contents were determined. Gamma-ray spectra of the samples were collected with a HpGe detector. ¹³⁷Cs was the major isotope observed. Activity of most litter samples were below 1000 Bq/kg, while most of the moss samples had activities below 5000 Bq/kg, there were a few with higher ¹³⁷Cs activities. Surface soil samples generally had activities less than 2000 Bq/kg and depth profiles of cesium activities in the soil cores showed regional variations.     

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.     

Concentration and behavior of radiocesium in higher basidiomycetes in some Kanto and the Koshin districts, Japan

Concentration of 137Cs, 134Cs and potassium were measured in several higher fungi and in substrates, soils, woods and litters in some Kanto and the Koshin districts, Japan, following the Chernobyl accident during October to November 1989. 137Cs concentrations in fungi were in the range of 0.7-101 Bq kg-1.fresh. Maximum 137Cs level in them was observed in Boletopsis leucomelas (Pers.: Fr.) Fayod. Significnatly higher levels of concentration ratios of 137Cs in fungi to substrates (e.g.; 137Cs concentration.fresh in fungus/137Cs concentration.dry in soil), 10(-1) to 10 x 10(-1), were found nearly 10 to 1000 times as much as leaf vegetables, root crops and potatoes to substrates. It was confirmed that levels of concentration ratios of potassium were similar to those of 137Cs. In all fungi, 134Cs which released from the Chernobyl accident and is not present in nuclear weapons fallout was not detected.     

Accumulation of137Cs by mushrooms from Rogozno area of Poland over the period 1984–1988

The concentration of naturally occurring⁴⁰K and¹³⁷Cs from fallout were determined in various mushrooms as well as in a few samples of forest soil from the same region over the period of 1984–1988. The¹³⁷Cs content in mushrooms before the reactor accident at Chernobyl was generally below 500 Bq kg⁻¹ dry matter, except Paxillus involutus /2700 Bq kg⁻¹/. A remarkable increase of the¹³⁷Cs activity /up to ten times/ was observed in 1986. For almost all examined species this activity remained basically at the same level for the next two years. No correlation between⁴⁰K and¹³⁷Cs in mushrooms has been found.     

Micellar enhanced microfiltration of strontium

Gamma-ray spectroscopy has been widely used in many areas of applied science. We have used the method to compare the¹³⁷Cs contamination in fungi collected in central Sweden, Ukraine (Kiev region) and southern Ontario, Canada. Mean activities were comparable for Sweden and Ukraine, but were much lower in the North American samples. Many European mushroom species which are considered as prized edibles, contained unacceptably high levels of¹³⁷Cs (1 kBq/kg) and should not be sold for human consumption. By contrast, no activity in mushrooms collected in Ontario or northern Michigan exceed 1 kBq/kg. The excessive contamination in European mushrooms is primarily due to the Chemobyl reactor accident of 1986. However, our observations suggest that about 20% of the¹³⁷Cs contamination in the Ukraine is not due to this accident.     

Long-term 137Cs contamination of mushrooms following the Chernobyl fallout

In the aftermath of the Chernobyl accident high concentrations of ¹³⁷ Cs were found in mushrooms in several European countries and inSweden. Two edible mushrooms species were selected for a long-term investigationin order to evaluate the ¹³⁷Cs contamination over a long time.Samples of Suillus variegatus and Cantharellus spp. were collected from 1986to 1998 and their ¹³⁷ Cs contents assessed. The results show thatthe activity of ¹³⁷Cs remained more or less constant in Suillusvariegatus, while it increased in Cantharellus spp. This reflects the forestecosystem of the mushrooms, where nutrient-poor substrates, rich in organicsubstance and with high pH maintain ¹³⁷Cs available for uptake.A decay-correction of the time distribution shows that radioactive decay appearsto be the main factor affecting the content of ¹³⁷Cs in mushrooms,at least in the medium term.     

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.     

Fat tissue is not a reservoir for radiocesium in wild boars

Meat of wild boars is not only known for high ¹³⁷Cs activity concentrations but also for the remarkable constancy of these levels. Even decades after the Chernobyl accident, the ¹³⁷Cs levels in wild boar meat in Central Europe have not declined but even partly increased. In the present study, we investigated an unusual hypothesis for this very unusual phenomenon: may the boars’ fat tissue act as a reservoir for radiocesium? We investigated fat and muscle tissues of four wild boars in Western Germany and found that the ¹³⁷Cs concentrations in fat were in the range of 10–30% of the respective activities in muscle tissue. Hence, the hypothesis was refuted.

     

Long-term transfer of <Superscript>137</Superscript>Cs from soil to mushrooms in a semi-natural environment

The radioactive contamination following the Chernobyl accident resulted in high concentrations of ¹³⁷Cs in several mushrooms species. Mushroom samples were collected in a forest environment between 1986 and 2007 and the transfer of ¹³⁷Cs to two edible species, Suillus variegatus and Cantharellus spp., was investigated. The ¹³⁷Cs uptake by the collected samples did not decrease over time and in Cantharellus spp. a significant increase was observed. Most of the ¹³⁷Cs in soil still appears to be available for uptake and radioactive decay of the radionuclide is likely the main factor for the reduction of ¹³⁷Cs in a forest ecosystem.     

Some aspects of radioactive contamination after Chernobyl accident in Romania

After the Chernobyl disaster, the radioactive cloud passage over Romania beginning with the April 30th, 1986 caused fall-out of different intensities in different regions.. The principal contributors to the radioactive exposure during the month of May and rest of 1986 were the short and medium half-live radionuclides: ¹³²Te+¹³²I, ¹³¹I, ¹⁴⁰Ba+¹⁴⁰La, ¹⁰³Ru+¹⁰³Rh, ¹⁰⁶Ru+¹⁰⁶Rh, ⁹⁵Zr+⁹⁵Nb, ¹³⁶Cs, ¹³⁴Cs, ¹⁴¹Ce, ¹⁴⁴Ce and ¹²⁵Sb. After four-five years only ¹³⁷Cs and ⁹⁰Sr remained significant radioactive contaminants. During May 1986 the grass was the mostly affected component of the environment and it contaminated rapidly the majority of foods. Measurements made on the daily gathered pollen samples and eggs during May 1986 clearly indicated that these samples can be used as bioindicators of radioactive contamination of the atmospheric air and, respectively, for soil and grass. Regarding soil contamination, the higher ^134+137Cs deposits in Romania following the northeast-southwest direction were measured, some of these being above 80 kBq/m². This direction is the same with the cloud passage over Romania during the first week of May 1986 and it was confirmed by measurements in the former Yugoslavia, Albania, Greece, and south of Italy.     

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 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/.     

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.