Transfer factors and effective half-lives of (134)Cs and (137)Cs in different environmental sample types obtained from Northern Finland: case Fukushima accident.
The Fukushima NPP accident caused a small but detectable cesium fallout in northern Finland, of the order of 1 Bq/m(2). This fallout transferred further to soil, water, flora and fauna. By using modern HPGe detector systems traces of (134)Cs from the Fukushima fallout were observed in various samples of biota. In northern Finland different types of environmental samples such as reindeer meat, berries, fish, lichens and wolf were collected during 2011-2013. The observed (134)Cs concentrations varied from 0.1 Bq/kg to a few Bq/kg. By using the known (134)Cs/(137)Cs ratio observed in Fukushima fallout the increase of the Fukushima accident to the (137)Cs concentrations was found to vary from 0.06 % to 6.9 % depending on the sample type. The aggregated transfer factors (Tag) and effective half-lives (Teff) for (134)Cs and (137)Cs were also determined and then compared with known values found from earlier studies which are calculated based on the fallout from the Chernobyl accident. Generally, the Tag and Teff values determined in this study were found to agree with the values found in the earlier studies. The Teff values were sample-type specific and were found to vary from 0.91 to 2.1 years for (134)Cs and the estimates for (137)Cs ranged between 1.6 and 19 years. Interestingly, the ground lichens had the longest Teff whereas the beard lichen had the shortest. In fauna, highest Tag values were determined for wolf meat ranging between 1.0 and 2.2 m(2)/kg. In flora, the highest Tag values were determined for beard lichens, ranging from 1.9 m(2)/kg to 3.5 m(2)/kg.
Radiation and Nuclear Safety Authority - STUK, Regional Laboratory in Northern Finland, Lähteentie 2, FIN-96400 Rovaniemi, Finland.
Matias
M
Koivurova
Radiation and Nuclear Safety Authority - STUK, Regional Laboratory in Northern Finland, Lähteentie 2, FIN-96400 Rovaniemi, Finland. Electronic address: ari.leppanen@stuk.fi.
Ari-Pekka
AP
Leppänen
Radiation and Nuclear Safety Authority - STUK, Regional Laboratory in Northern Finland, Lähteentie 2, FIN-96400 Rovaniemi, Finland.
Antti
A
Kallio
D000818:Animals; D002588:Cesium Radioisotopes / Q000032:analysis / Q000378:metabolism*; D047852:Chernobyl Nuclear Accident; D005387:Finland; D005638:Fruit / Q000378:metabolism; D062406:Fukushima Nuclear Accident; D006207:Half-Life; D008011:Lichens / Q000378:metabolism; D008322:Mammals / Q000378:metabolism; D011834:Radiation Monitoring; D011847:Radioactive Fallout / Q000032:analysis*
D002588:Cesium Radioisotopes; D011847:Radioactive Fallout
(134)Cs; (137)Cs; Aggregated transfer factor; Effective half-life; Fukushima; Northern Finland