Back to Search
Start Over
Long-term investigations of post-Chernobyl radiocaesium in fallout and air in North Croatia
- Publication Year :
- 2009
-
Abstract
- The long-term behaviour of (137)Cs 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 (137)Cs activity concentrations in air and annual total deposition fluxes (wet plus dry) decreased from 2.8 x 10(-4) Bq m(-3) in September 1986 to 3.0 x 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 (137)Cs activity concentrations to the theoretical curve the ecological half-lives of (137)Cs 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 (137)Cs activity concentrations in air and fallout total caesium deposition velocity of (3.34 +/- 3.13) x 10(-2) ms(-1) was estimated with median value being 2.13 x 10(-2) ms(-1). Such relatively high (137)Cs deposition velocities compared with pre-Chernobyl ones, are characteristic for the post-Chernobyl period and, according to Stokes' settling law, indicate that the diameters of aerosol particles associated with (137)Cs originated from the Chernobyl accident are pretty large, i.e.1 microm. (134)Cs/(137)Cs activity ratio in fallout and in air has been found to be similar to the theoretically predicted values, initial value being about 0.5 and decreasing according to differential radioactive decay. The similar ratio has been observed in most of the other environmental samples.
- Subjects :
- Radioactive Fallout
Time Factors
Human environment
Croatia
chemistry.chemical_element
Management, Monitoring, Policy and Law
Atmospheric sciences
137Cs
134Cs
Chernobyl accident
deposition flux
deposition velocity
ecological half-life
Settling
Radiation Monitoring
Radioactive contamination
Humans
Soil Pollutants, Radioactive
General Environmental Science
Hydrology
General Medicine
Pollution
Monitoring program
Aerosol
Deposition (aerosol physics)
Chernobyl Nuclear Accident
chemistry
Air Pollutants, Radioactive
Cesium Radioisotopes
Caesium
Environmental science
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....aeb58e286869585a18cd4469dab556ce