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.     

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/.     

90Sr and137Cs in fallout from Chernobyl in the Bucharest-Măgurele area during 1986–1987

This work shows the variation of⁹⁰Sr and¹³⁷Cs in atmospheric fallout in the Bucharest-Mgurele area during 1986–1987. The amount of⁹⁰Sr in the fallout was estimated to be about 900 Bq.m^–2 in 1986 and about 9.2 Bq.m^–2 in 1987. The amount of¹³⁷Cs was estimated to be 13300 and 615 Bq.m^–2 in 1986 and 1987, respectively.     

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.     

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.     

Simultaneous determination of some long-lived semivolatile radionuclides in environmental samples

A radiochemical method is presented to determine simultaneously the long-lived semivolatile radionuclides⁷⁹Se,⁹⁹Tc,¹⁰⁶Ru,¹²⁵Sb,^125mTe,^127mTe,¹³⁴Cs and¹³⁷Cs in environmental samples. The pure -emitters⁷⁹Se and⁹⁹Tc are counted in a low-level gas flow counter, the -emitters in a -spectrometer with a high purity well-type Ge detector. The procedure was tested using environmental samples with known concentrations of⁹⁹Tc,¹⁰⁶Ru,¹²⁵Sb,¹³⁴Cs and¹³⁷Cs.     

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.     

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.     

Comparison of DSC and optical transmission measurements of polymorphic transitions

Using optical measurements on single crystals, the speed of first order transitions (K₂Cr207, KNO₃, AgNO₃) was determined and compared with the strongly smeared DSC signals. Such optical measurements are proposed to select materials which are suitable for the determination of the DSC apparatus function.

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Zusammenfassung Mit Hilfe von optischen Messungen wird die Geschwindigkeit von polymorphen Phasenumwandlungen 1. Ordnung (K₂Cr₂O₇, KNO₃, AgNO₃) bestimmt und mit entsprechenden stark verschmierten DSC-Signalen verglichen. Derartige optische Messungen erscheinen geeignet, um Substanzen zu suchen, welche für die Bestimmung der DSC-Apparatefunktion geeignet sind.

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K₂Cr₂O₇, KNO₃ AgNO₃ $ , $ . , $ .

     

Environmental radioactivity level in the Ceranavodă area /Romania/ between 1981 and 1983

The environmental factors considered are: surface water, ground water, drinking water, soil, sediment and spontaneous vegetation. The analyses performed showed a low level of radioisotopes. The mean values recorded were: 4.22×10^–3 Bq dm^–3 for¹³⁷Cs, 2.97×10^–3 Bq dm^–3 for⁹⁰Sr, 14.9 Bq dm^–3 for³H and 1.07 g dm^–3 for U, in the Danube waters. The -spectrometric analysies revealed lines corresponding to⁴⁰K and the to the natural decay series of U and Th. There have been also identified the artificial radionuclides¹³⁷Cs and⁶⁰Co in sediment,⁹⁵Zr and⁹⁵Nb in the 1981 vegetation. All artificial isotopes resulted from atmospheric fallout.     

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.     

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.     

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.     

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.     

Radioactivity in the highly contaminated area near the Chernobyl site

Field measurements of radioactivity were performed in highly contaminated areas around Chernobyl in the summer of 1990. Six radionuclides including the most dominant¹³⁷Cs have been identified in soil samples through -ray spectrometry. The relation between the -ray dose rate above the ground and the radioactivity density in soils has been investigated. The external dose from deposited radiocesium for the period of 70 years after the deposition has been evaluated to be about 5 mSv per 1 and 0.5 Ci km^–2 of¹³⁷Cs and¹³⁴Cs deposition, respectively.     

On the limits of low level measurements of137Cs as a natural radiotracer

Study of¹³⁷Cs in rivers implies knowledge of its adsorption behaviour towards particulate matter and sediments and the possibility of low-level counting of water and solids. As the adsorption isotherms and kinetics will be discussed separately, this text focuses on the low level counting of¹³⁷Cs. The use of flat-ended Ge(Li) detectors is compared to that of an anticoincidence array after preconcentration of the cesium ions into a 0.5 ml solid aliquot. The lower limits of determination at a relative standard deviation of 10% are 10 Bq · kg^–1 for as received aliquots on a flat Ge(Li) detector and 10 mBq in case of preconcentration from water and counting in the anticoincidence facility. The eventual improvement of the accuracy by applying moving average and smoothing procedures are considered.     

Fallout analysis of atmospheric water precipitations

Summary A rapid ion-exchange method for the determination of ¹³⁷Cs, ⁸⁹Sr, and ⁹⁰Sr in rain-, snow-, cistern-, and soft surface-waters is presented. The sorption of 2–30 l samples with a calcium content up to 300 mg is carried out on a specially shaped column filled with Dowex 50, X-8 or Dowex 50 W, X-8. Radiocaesium is washed from the column with 0,6 M ammonium glycolate/0.2 M NaCl, pH 5, radio-strontium with 1.0 M ammonium glycolate/0.3 M NaCl, pH 5. After their isolation from the respective eluates the radio-nuclides are counted on a low-background beta-counter: ¹³⁷Cs as Cs-dipicrylaminate, ⁸⁹Sr/⁹⁰Sr as SrCO₃, and ⁹⁰Y as Y₂O₃ in cases of indirect ⁹⁰Sr determination. The mean chemical recoveries of added carriers amount to 85% for caesium, 95% for strontium and 95% for yttrium. At levels of a few picocuries, in parallel determinations, the deviations of the results for ¹³⁷Cs and ⁹⁰Sr from respective mean values generally do not exceed ±5%. With a 30 l sample the limit of detection amounts to 0.006 Ci/l for ¹³⁷Cs and 0.005 Ci/l for ⁹⁰Sr.

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Zusammenfassung Für die Bestimmung von ¹³⁷Cs, ⁸⁹Sr und ⁹⁰Sr in Regen-, Schnee-, Zisternen- und weichem Oberflächenwasser wird eine schnelle Ionenaustausch-methode vorgeschlagen. Die Sorption von 2–30 l Wasserproben mit einem Calciumgehalt bis zu 300 mg wird mit einer besonders gestalteten, mit Dowex 50, X-8 oder Dowex 50 W, X-8, gefüllten Säule durchgeführt. Aus der Kolonne werden Radio-Caesium mit 0,6 M Ammoniumglykolat/ 0,2 M NaCl, pH 5 und Radio-Strontium mit 1,0 M Ammoniumglykolat/ 0,3 M NaCl, pH 5 eluiert. Nach ihrer Isolierung aus den entsprechenden Eluatsfraktionen werden die Radio-Nuklide in einem Beta-Antikoinzidenzzähler gemessen: ¹³⁷Cs als Cs-Dipikrylaminat, ⁸⁹Sr/⁹⁰Sr als SrCO₃, und ⁹⁰Y als Y₂O₃ im Fall der indirekten ⁹⁰Sr-Bestimmung. Die durchschnittliche Rückgewinnung der zugesetzten Träger beträgt 85% für Caesium, 95% für Strontium und 95% für Yttrium. In Parallelbestimmungen überschreiten bei Gehalten von einigen Ci/l die Abweichungen der ¹³⁷Cs- und ⁹⁰Sr-Werte von den entsprechenden Mittelwerten im allgemein nicht ±5%. Bei Anwendung einer 30 l-Wasserprobe beträgt die untere Nachweisgrenze 0,006 Ci/l für ¹³⁷Cs und 0,005 gmCi/l für ⁹⁰Sr.

     

137Cs,trace and toxic elements distribution in Austrian mushrooms

Various mushroom species have been analyzed for their elemental composition (i.e., Al, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn) by means of ICP-AES. The accuracy of the measurements was confirmed by analyzing a series of the same samples by short time activation analysis. The data were evaluated statistically including the values of¹³⁷Cs. The results denote that the distribution of these elements and their correlation of these elements and their correlation coefficients are highly distinctive for each mushroom species. K, Na and P were found to correlate negatively with¹³⁷Cs in most species. Suillus grevillei and Cantharellus cibarius show high Be values (0.27 and 0.30 g g^–1, respectively), while Pb was high in Suillus grevillei (16.3 g g^–1) and Amanita rubescens (9.3 g g^–1). Higher levels of Cd were found in Rozites caperata and Russula vesca with a mean of 9.2 and 16.1 g g^–1, respectively. Cluster analysis was applied to classify these samples according to their botanical species using their elemental composition. The concentrations of Al, Cr, Mn, Na and¹³⁷Cs have no influence on the classification of these samples.     

Activity of137Cs in some foodstuffs imported to the Slovak Republic

The results of radiocesium activity of some foodstuffs imported to the Slovak Republic in the period from January 1988 to July 1995 are presented. The analysed samples were homogenized, packed into 0.451 Marinelli beakers and then measured by direct semiconductor, -spectrometry for 10 000–50 000 seconds. The levels of¹³⁷Cs in various foodstuffs varied quite widely from Minimum Detectable Activity (MDA)=0.4 to 80.2 Bq/kg. Concentrations of¹³⁷Cs in fish and fish products were in general higher than those in beef and pork.