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

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作者：

C Papastefanou，A Ioannidou，S Stoulos，M Manolopoulou

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摘要：

Atmospheric (tropospheric) depositional fluxes of the naturally occurring 7 Be of cosmogenic origin and 137 Cs 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 7 Be varied between 854 Bq/m 2 (1987) and 1242 Bq/m 2 (1992), showing a minimum in the years 1988–1989. The annual total deposition fluxes of 137 Cs varied between 183 Bq/m 2 (1987) and 16.4 Bq/m 2 (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 7 Be was from 0.3 cm/s (1988) up to 0.8 cm/s (1991), while for 137 Cs the corresponding values were much higher, hence 137 Cs was associated with larger atmospheric particles. High 7 Be concentrations in air were related to the very little solar activity (1987–1988 and 1993–1994), while low 7 Be concentrations in air related to the high solar activity (1989–1991). Maximum 137 Cs concentrations in air were registered during the spring 1991 and 1992, reflecting some stratospheric inputs. An unusual highly elevated value of 137 Cs concentration in air, reaching 0.25 mBg/m 3 , was observed during the summer 1990.

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关键词：

Atmospheric depositional flux Cosmogenic radionuclides Chernobyl accident

DOI：

10.1016/0048-9697(95)04608-4

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年份：

1995