hrvatski

Radioaktivnost mahovine pokazatelj radiološkog onečišćenja

Mosses, characterised by a slow growth, are able to efficiently accumulate different radionuclides from the environment to a much higher degree than other vegetation. Consequently, mosses are sensitive bioindicators of radioactive contamination in various ecosystems. Radioactivity released into air after the accident in the Fukushima Dai-ichi nuclear power plant has become part of atmospheric processes and the transport of matter in the biosphere. During the last five years, mosses were sampled at three selected locations: in the courtyard of the Institute for medical research in Zagreb (IMI), at an active gas well in Podravina (Molve) and near orchards and vineyards in Kloštar Ivanić. Moss samples were before analysis dried in an oven and after that usually ashed. All the samples were analysed by means of gamma-ray spectrometry using HP GMX and/or Ge(Li) detectors connected with a data acquisition system. The obtained results show the following relations between 137Cs and 134Cs activity concentrations on selected locations: 137Cs: AKloštar < AIMI < AMolve 134Cs: AMolve < AKloštar < AIMI It is shown that the differences in 137Cs activity concentrations are statistically significant. There are at least two mechanisms present in mosses, one based on the transfer of metals (caesium) with dust uplifted from soil and the other one based on the diffusion in aqueous solution wetting a moss. We assume that the differences in the 137Cs activity concentrations are caused by the mosses growing at different locations with different fallout characteristics (wet and dry deposition). The 134Cs activity concentration is small everywhere, near the values of the detection limits. The study was conducted in the Radiation Protection Unit of the Institute for Medical Research and Occupational Health in Zagreb, as a part of an extensive monitoring program of the Croatian environment.

radioktivnost, mahovina, radiološko onečišćenje

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