Chemical fraction of radiactive cesium in atmospheric aerosol in Prague after the Chernobyl accident

Aerosol filters exposed during the period of direct contamination after the NPP accident at Chernobyl have been analyzed with the aim to determine the physicochemical forms of¹³⁷Cs. A modified sequential analysis of solubility according to Tessier was used. It was shown that the content of water-soluble radiocesium fraction (about 45%) was substantially lower when compared with the analysis results of aerosols collected in the U.K. Another marked difference was found in the case of undissolved residue, where, on the contrary, the¹³⁷Cs content was higher. No significant differences were found in the composition of samples collected during the time period of, May 1–May 6, 1986. In a sample collected in a later period a lower percentage of water soluble¹³⁷Cs fraction and a higher percentage of¹³⁷Cs in the undissolved residue was found.