Naturally occurring radionuclides of paper ashes and their effect in the environment

The concentrations of naturally occurring radionuclides (226Ra, 228Ra, 228Th, and 40K) in ashes of papers such as magazines and newspapers were determined from the nuclide concentrations in the papers and the ash contents of the papers. The average 226Ra, 228Ra, 228Th, and 40K concentrations in the 34 ashes were respectively 27, 68, 75, and 75Bq kg-1. The radium equivalent activities of the ashes were calculated to evaluate the hazard of γ-ray radiation from the ashes in the environment. A copying paper sample showed a high radium equivalent activity of 602Bq kg-1. However, the average radium equivalent activity was 140Bq kg-1 and was lower than the level that causes an environmental health problem. (author)