Distribution of pre- and post-Chernobyl radiocaesium with particle size fractions of soils

Title: Distribution of pre- and post-Chernobyl radiocaesium with particle size fractions of soils

Author: Pasquale Spezzano

Reference: Journal of Environmental Radioactivity, Volume 83, Issue 2, 2005, Pages 117-127

DOI: http://dx.doi.org/10.1016/j.jenvrad.2005.02.002

Keywords: Chernobyl fallout; Weapons fallout; Soil; Radiocaesium; Particle size distribution

Abstract: The association of radiocaesium with particle size fractions separated by sieving and settling from soils sampled eight years after the Chernobyl accident has been determined. The three size fractions were: 63 μm. ¹³⁷Cs in the soil samples was associated essentially with the finer size fractions, which generally showed specific activities 3–5 times higher than the bulk samples.

Activity ratios of ¹³⁴Cs/¹³⁷Cs in the clay-sized fractions appear to be lower with respect to the corresponding values in bulk soil samples. This result indicates that some differences still exists in the particle size distribution between ¹³⁷Cs originating from nuclear weapons, which has been in the soil for decades after fallout, and ¹³⁷Cs coming from the Chernobyl accident, eight years after the deposition event. This behaviour could be related to “ageing” processes of radiocaesium in soils.

URL: http://www.sciencedirect.com/science/article/pii/S0265931X05000548

Seasonal 7Be and 137Cs activities in surface air before and after the Chernobyl event

Title: Seasonal 7Be and 137Cs activities in surface air before and after the Chernobyl event

Author: A. Kulan

Reference: Journal of Environmental Radioactivity, Volume 90, Issue 2, 2006, Pages 140-150

DOI: http://dx.doi.org/10.1016/j.jenvrad.2006.06.010

Keywords: ⁷Be; ¹³⁷Cs; Atmosphere; Aerosols; Chernobyl fallout; Nuclear weapons fallout; Sweden; Europe

Abstract: Seasonal fluctuations of cosmogenic ⁷Be (T_1/2 = 53.4 days) and anthropogenic ¹³⁷Cs (T_1/2 = 30 years) activities in surface air (aerosols) have been extracted from a long data record (1972–2000) at high latitude (56°N–68°N, Sweden). Normalization to weekly average values was used to control long-term trends so that cyclical trends could be investigated. Enhanced ⁷Be activity was observed in spring and summer seasons and likely relates to the seasonal thinning of the tropopause. Variations in the ¹³⁷Cs activity record seem to reflect how the isotope was injected in the atmosphere (stratospheric from bomb tests and tropospheric from the Chernobyl accident) and subsequent transport mechanisms. Accordingly, until 1986, the surface air ¹³⁷Cs activity was strongly related to nuclear weapons test fallout and exhibits temporal fluctuations resembling the ⁷Be. Conversely, since 1986 the Chernobyl-produced ¹³⁷Cs dominates the long-term record that shows annual cycles that are strongly controlled by atmospheric boundary layer conditions. Additionally, short-term data within the post-Chernobyl period suggest subtle intrusion of air masses rich in ¹³⁷Cs that may occur throughout the year, and differences resulting from spatial occurrence at these latitudes. This is an important observation that may have to do with year-to-year variation and calls for caution when interpreting short-term data records.

URL: http://www.sciencedirect.com/science/article/pii/S0265931X06001032

Seasonal 7 Be and 137 Cs activities in surface air before and after the Chernobyl event

Title: Seasonal 7 Be and 137 Cs activities in surface air before and after the Chernobyl event

Author: Kulan, A.

Reference: Journal of Environmental Radioactivity, 90 (2), p.140-150, Jan 2006

DOI: 10.1016/j.jenvrad.2006.06.010

Keywords: ⁷Be; ¹³⁷Cs; Atmosphere; Aerosols; Chernobyl fallout; Nuclear weapons fallout; Sweden; Europe

Abstract: Seasonal fluctuations of cosmogenic ⁷Be (T_1/2 = 53.4 days) and anthropogenic ¹³⁷Cs (T_1/2 = 30 years) activities in surface air (aerosols) have been extracted from a long data record (1972–2000) at high latitude (56°N–68°N, Sweden). Normalization to weekly average values was used to control long-term trends so that cyclical trends could be investigated. Enhanced ⁷Be activity was observed in spring and summer seasons and likely relates to the seasonal thinning of the tropopause. Variations in the ¹³⁷Cs activity record seem to reflect how the isotope was injected in the atmosphere (stratospheric from bomb tests and tropospheric from the Chernobyl accident) and subsequent transport mechanisms. Accordingly, until 1986, the surface air ¹³⁷Cs activity was strongly related to nuclear weapons test fallout and exhibits temporal fluctuations resembling the ⁷Be. Conversely, since 1986 the Chernobyl-produced ¹³⁷Cs dominates the long-term record that shows annual cycles that are strongly controlled by atmospheric boundary layer conditions. Additionally, short-term data within the post-Chernobyl period suggest subtle intrusion of air masses rich in ¹³⁷Cs that may occur throughout the year, and differences resulting from spatial occurrence at these latitudes. This is an important observation that may have to do with year-to-year variation and calls for caution when interpreting short-term data records.

URL: http://www.sciencedirect.com/science/article/pii/S0265931X06001032