Plutonium traces in atmospheric precipitation and in aerosols from Krakow and Bialystok

Abstract

The appearance of plutonium isotopes in the environment was connected with the human activity, mainly: nuclear weapon tests (global fallout), nuclear accident in Chernobyl (1986), disintegration of satellite SNAP 9 (1963) and releases from nuclear reprocessing factories. At present, the concentration of plutonium in the atmosphere is very small but still observable.The aim of the study is to report and to discuss the results of plutonium alpha-emitters determination from sampling aerosols in air (Krakow 1990–1998, 2001–2002 and Bialystok 1996–1998, 2001) and in precipitation (Krakow 2005–2006). Plutonium activity concentration in air samples (in Krakow and Bialystok) varied in range: 0.22±0.04 nBq/mOne of the mechanisms responsible for the airborne plutonium is resuspension but on the other hand the main source of plutonium in the air seems to be marines aerosols from North See. This new hypothesis will be checked during the future research. The most interesting finding is the seasonal variation of plutonium air concentration. The conclusion from calculated ratio of plutonium isotopes (

Cosmogenic 22Na, 7Be and terrestrial 137Cs, 40K radionuclides in ground level air samples collected weekly in Kraków (Poland) over years 2003–2006

“…It cannot be the cosmogenic component, as for cosmogenic radionuclides the minimum is observed in cold seasons, so the emission from burned biomass, namely wood, seems to be the most likely explanation [ 52 ]. We know from other studies [ 55 ] that in Kraków winters display the lowest activity concentration for plutonium in air, with relatively highest 238 Pu/ 239+240 Pu ratio, which might suggest sea-spray from the North Sea (or other spent nuclear fuel) to be an important source of radionuclides in winter. However, the massive sea spray should increase 40 K, what is not observed.…”

Sources of plutonium in the atmosphere and stratosphere-troposphere mixing

“…It has been pointed out that sea spray may be another potential source of plutonium in the atmosphere7374. However, the contribution of plutonium from sea salt to atmospheric plutonium deposition is much lower than that from soil (<0.3%)4.…”

Rapid method for plutonium-241 determination in soil samples

“…According to the literature data, the typical global fallout ratio 238 Pu/ 239+240 Pu is ranged 0.03–0.05, and for Chernobyl fallout is 0.3–0.65 [19]. The observed ratio indicates that the upper soil layer is contaminated mainly with Chernobyl fallout and the lower rather with a global one.…”