Radioactivity of 137Cs in papers and migration of the nuclide in the environment

The 137Cs contents of papers such as magazines and newspapers printed in Japan were determined by gamma-ray spectrometry. The average 137Cs content of weekly general interest magazines was 0.95 Bq kg-1 and far higher than those of other kinds of samples. The result of pholorogluinol color test showed that the main printed pages of the weekly general interest magazines were chiefly made of mechanical pulp. Possibly the pages held 137Cs brought by wood, raw material of paper, and that accounted for the high 137Cs content of the magazines. The experimental result suggested that 137Cs was removed from wood into aqueous solution in the production of chemical pulp. Cesium-137 radioactivity removed during paper manufacturing in the year 2000 in Japan was estimated to be 15 GBq, and the influence of paper manufacturing on the migration of 137Cs in the environment was discussed. (author)