Atmospheric deposition of cosmogenic 7Be and 137Cs from fallout of the Chernobyl accident

Title: Atmospheric deposition of cosmogenic 7Be and 137Cs from fallout of the Chernobyl accident

Author: C. Papastefanou, A. Ioannidou, S. Stoulos, M. Manolopoulou

Reference: Science of The Total Environment, Volume 170, Issues 1–2, 18 August 1995, Pages 151-156

DOI: http://dx.doi.org/10.1016/0048-9697(95)04608-4

Keywords: Atmospheric depositional flux; Cosmogenic radionuclides; Chernobyl accident

Abstract: Atmospheric (tropospheric) depositional fluxes of the naturally occurring ⁷Be of cosmogenic origin and ¹³⁷Cs from fallout of the Chernobyl accident were measured over a 7-year period (January 1987–December 1993) at Thessaloniki, Greece (40° 38′N, 22° 58′E). The annual total deposition fluxes of ⁷Be varied between 854 Bq/m² (1987) and 1242 Bq/m² (1992), showing a minimum in the years 1988–1989. The annual total deposition fluxes of ¹³⁷Cs varied between 183 Bq/m² (1987) and 16.4 Bq/m² (1992), showing a significant decrease as expected for natural removal and radioactive decay and no new releases from nuclear facilities or weapons testing. The annual average total deposition velocity for ⁷Be was from 0.3 cm/s (1988) up to 0.8 cm/s (1991), while for ¹³⁷Cs the corresponding values were much higher, hence ¹³⁷Cs was associated with larger atmospheric particles. High ⁷Be concentrations in air were related to the very little solar activity (1987–1988 and 1993–1994), while low ⁷Be concentrations in air related to the high solar activity (1989–1991). Maximum ¹³⁷Cs concentrations in air were registered during the spring 1991 and 1992, reflecting some stratospheric inputs. An unusual highly elevated value of ¹³⁷Cs concentration in air, reaching 0.25 mBg/m³, was observed during the summer 1990.

URL: http://www.sciencedirect.com/science/article/pii/0048969795046084