A Study of the Transfer of Radionuclides in the Environment by the Analysis of Plant Samples

Research Project

Project/Area Number	08680550
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Environmental dynamic analysis
Research Institution	the University of Tokyo
Principal Investigator	KOBASHI Asaya the University of Tokyo, School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (60114477)
Co-Investigator(Kenkyū-buntansha)	TANIKAWA Masashi the University of Tokyo, School of Science, Research Associate, 大学院・理学系研究科, 助手 (90251412)
Project Period (FY)	1996 – 1997
Project Status	Completed (Fiscal Year 1997)
Budget Amount *help	¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
Keywords	paper / newspaper / book / naturally occurring radionuclides / cesium-137 / radioactivity / filler / fallout
Research Abstract	The main constituent of paper is pulp produced from plant. In this research, we measured the radioactivity content of papers to investigate the transfer of radionuclides from plant to paper and from paper to the environment. The ^<137>Cs contents of printed pages and hardcovers of books printed during the 1960s in Japan were determined. The printed pages contained almost no ^<137> Cs (below 0.2 Bq/kg). The covers in which rice straw board was used as core showed high ^<137>Cs concentrations (1.0-5.7 Bq/kg), whereas ^<137>Cs was not detected in the cover with chip board core. The covers with board core made partly of rice straw pulp showed intermediate concentrations (0.2-1.0 Bq/kg). These facts suggested that ^<137>Cs contained in the books came mostly from rice straw. The reason for the similarity of the pattern of ^<137>Cs concentration in the book vs. the year of its issue to that of annual ^<137>Cs fallout deposition was dissussed. Newspapers and information bussiness papers peoduced during the 1990s were analyzed for radioactivities of the naturally occurring radionuclides (^<226>Ra, ^<228>Ra, ^<228>Th, and ^<40>K) and a fallout muclide (^<137>Cs). The concentrations of the naturally occurring radionuclides were low in the Newspapers. The ^<228>Th contents of an information bussiness paper were as high as 30 Bq/kg. These nuclides were maybe present in kalinite filler used in the paper. ^<137>Cs was not detected in the information bussiness papers. whereas the radionuclide detected in all the mewspapers (0.1-0.2Bq/kg). ^<137>Cs contained in the newspapers was maybe brought with mechanical pulp, the main constituent of the newspapers. Based on the analytical data, the environmental effect of radioactivity released from incinerators by burning wastepapers was discussed.