查看文章

The long-term behaviour of ¹³⁷Cs activity concentrations in air and fallout has been studied in the city of Zagreb for the post-Chernobyl period (1986–2006) as a part of an extended monitoring program of radioactive contamination of human environment in Croatia. Annual mean ¹³⁷Cs activity concentrations in air and annual total deposition fluxes (wet plus dry) decreased from 2.8 × 10⁻⁴ Bq m⁻³ in September 1986 to 3.0 × 10⁻⁶ Bq m⁻³ in last quarter of 2006 and from 6,410 Bq m⁻² year⁻¹ in 1986 to 2 Bq m⁻² year⁻¹ in 2006 respectively. By fitting the measured ¹³⁷Cs activity concentrations to the theoretical curve the ecological half-lives of ¹³⁷Cs in air and fallout were estimated with respective values of 0.46 and 0.54 years for immediate post-Chernobyl period, increasing to 5.52 and 3.97 years afterwards. Using the data on ¹³⁷Cs activity concentrations in air and fallout total caesium deposition …