Andrzej Komosa

MIGRATION OF PLUTONIUM ISOTOPES IN FOREST SOIL PROFILES IN LUBLIN REGION (EASTERN POLAND)

The distribution of Pu isotopes in three profiles of forest soil in Lublin region was determined. The retention half-time and migration velocity of239,240Pu originated from global and Chernobyl fallouts was calculated. The average rate of migration of the global fallout plutonium was 0.4 cm/year and that of the Chernobyl one 0.7 cm/year. Good correlation between Pu concentration and organic matter contents was found only in the case of podzolic soil profile. In two profiles a good negative correlation between Pu activity and exchangeable pH of the soil layer was determined.

Study on plutonium isotopes determination in soils from the region of Lublin (Poland)

Abstract The concentration of 239+240 Pu and 238 Pu has been determined in surface soils (0–2 cm) of the Lublin region, eastern Poland. The concentration of 239+240 Pu in all samples ranged from 0.076 to 0.337 Bq/kg dry weight of soil, and of 238 Pu from 0.008 to 0.036 Bq/kg. The minimum detectable amount (MDA) of 239+240 Pu was calculated to be 5 ± 2 mBq/kg of soil, and of 238 Pu 3 ± 1 mBq/kg. The fraction of 239+240 Pu originating from the Chernobyl accident ranged from 0 to 35%.

Study on geochemical association of plutonium in soil using sequential extraction procedure

Three kinds of soil, collected in various places (in northwestern and southeastern Poland and near Chernobyl) were used as a subject of sequential extraction and plutonium distribution study. The modified method of Tessier was applied to separate readily available, carbonate, organic, Fe/Mn oxide and residual fractions. Plutonium isotope activity in soil as well as in particular separated fractions was determined by means of alpha spectrometry. The method of plutonium separation and purification for alpha-spectrometric measurements was modified according to the chemical properties of the extracted fraction. It was found that the major part (about 90%) of 239,240Pu is bound to organic and Fe/Mn oxide fractions (in uncultivated soil samples of northwestern Poland and Chernobyl). In soil samples coming from river valley (southeastern Poland) almost equal amounts of plutonium are distributed between the available, organic and residual fractions.

Determination of plutonium in ground-level air aerosols collected on Petrianov filters

Determination of plutonium in air filters as modification of the procedure applied to soil samples is presented. The Petrianov filter with collected air aerosol and dust was submitted to direct leaching with 6M HCl. Co-precipitation with Fe(OH)3 and calcium oxalate, anion exchange separation and electrodeposition, and finally alpha spectrometry was used to determine the plutonium concentration in the samples. Mean activity of 239,240Pu in the air was 9.1 nBq/m3 (in 1998 and 1999). The problem of the radon progeny, 210Po, appearing on the alpha plutonium spectra is discussed. The correlation of plutonium concentration with mass of the collected dust was better than with an air volume passed through the filter.

Radon concentration in basements of old town buildings in the Lublin region, Poland

Radon concentration in basements of old buildings in the oldest towns of Lublin region (Zamość, Chelłm and Sandomierz) was determined. Two techniques were applied: passive (Pico-rad) and alpha-spectrometry for radon progeny concentration measurement (SILENA). It was found that only 7% of results exceeded a dose limit of 400 Bq·m-3, established for old buildings. Radon concentration levels ranged from 0.2 to 5150 Bq·m-3. Distribution of the results satisfied a log-normal relationship. Applying these two methods at the same time, the radioactive equilibrium factor of radon and its progeny was determined. In the underground ways, open for visitors, no higher radon concentration was observed.

Rapid method for plutonium-241 determination in soil samples

A simple and rapid procedure for the determination of plutonium isotopes in the environment is presented. The procedure combines alpha spectrometry, solvent extraction and liquid scintillation measurements to ensure that both alpha- and beta-emitting isotopes are determined. Of five tested extractants, bis-(2-ethylhexyl) phosphoric acid was found to be the best choice. The procedure was applied to soil samples contaminated with Chernobyl fallout.

Study on the Horizontal Transport of Some Radionuclides in the Wieprz River Valley

A horizontal transport of radionuclides was studied by the analysis of the radioactivity of the surface soil samples from valleys of Wieprz river and its bottom sediments. Natural gamma-isotopes (40K, 238U and 232Th series) antropogenic (134Cs and 137Cs) and alpha-isotopes 238Pu and 239,240Pu were measured. The different kind of bed rock and terrain configuration, influenced the radionuclide transportation from the soil to river bottom sediments. Radioactivity of the sediment samples is definitely lower than the soils. Very strong adsorption of isotopes in soil hinders their horizontal migration. Calculated 238Pu/239,240Pu ratio is characteristic for global fallout and about 90% of the 137Cs comes from Chernobyl.