Chernobyl fallout measurements in some Mediterranean biotas

Abstract

The radioactivity of various terrestrial vegetation leaves characteristic of Mediterrenean countries has been measured after the Chernobyl accident. In addition, we paid particular attention to lichens and seaweed which are considered as bioindicators of radioactive contamination. The measurements were performed by non-destructive way using both coaxial and planar HPGe detectors. For odd mass radionuclides having low energy lines, such as¹²⁵Sb or¹⁴¹Ce the sensitivity of the planar HPGe detector is better than the coaxial detector. The concentration of long lived fission nuclides remaining three months after the accident were found to be enhanced in needle form leaves and in lichens. The seaweed Sphaerococcus exhibits a strong specific activity for iodine and ruthenium and poor concentration for cesium nuclides. The activity ratios of different isotopes of the same element, measured in vegetation samples agree well with the values found by other authors in airborne aerosols. The activation nuclide¹¹⁰Ag^m is found in all samples with the same ratio¹¹⁰Ag^m/¹³⁷Cs=/1.0±0.2/×10⁻², as in the soil deposition.