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  • Author or Editor: N. Păunescu x
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Abstract  

Uranium and thorium have been determined in natural water samples by concentration on a cation-exchange resin, separation on an anionexchange resin and by measuring spectrophotometrically the compounds formed by U/IV/ and Th/IV/ with Arsenazo III. The recovery yield is higher than 90% for Th and about 80% for U.

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Abstract  

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.

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Abstract  

89Sr and90Sr were determined in the fallout of May 1986. The maximum values of 335 Bq/(m2.6 h) and 110 Bq/(m2.6 h) were observed on May 2 and 5. Throughout May 1986 a quantity of 860 Bq/m2 of90Sr, deposited from the fallout in the Bucharest-Mgurele area, was estimated.

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Abstract  

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.

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Abstract  

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.

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Abstract  

In Romaia, CANDU Nuclear Power Plant with five reactors of 600 MWe is under construction at Cernavoda town and in 1996 the first reactor was put in operation. The background level of tritium concentration was determined in preoperational stage. The mean values determined are: (7.4±5.5) Bq/l in air humidity, 3.1±1.0) Bq/l in water, (3.5±0.7) Bq/l in tissue water from vegetable and (4.9±1.7) Bq/l in tissue water from cereals. The transfer parameters for deposition from atmosphere on forage and crops (P14), and the contamination of land and vegetation by spray irrigation water, (P24) were evaluated at (29–49) and (0.90±0.27), respectively.

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Abstract  

The dynamics of137Cs soil-to-plant transfer has been studied for 21 vegetal species in an agricultural area not far from Bucharest, during a two year experiment started one year after the Chemobyl nuclear accident. The results, generally fitting in the value ranges found in literature, are discussed in the strict sense of the definition for soil-to-plant transfer of radionuclides.

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Abstract  

This paper presents the results of radioactivity studies of environmental factors such as surface water, sediment, aquatic vegetation and soil. The concentrations of137Cs,90Sr,3H, U, Ca, and Mg in water samples were determined by radiochemical and chemical methods. Gamma-spectrometric analyses were performed for all the samples. The analysis showed a decrease in concentrations of137Cs in water, aquatic vegetation and sediment, but a constant level of137Cs activity in soil (0–5 cm depth). The average concentrations of90Sr,3H, U, Ca and Mg were about 7 mBq/l, 11 Bq/l, 0.6 g/l 60 mg/l and 11 mg/l, respectively.

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