Bulletin of the Geological Society of Malaysia, Volume 43, Dec. 1999, pp. 337 – 343
1Institut Penyelidikan Teknologi Nuklear Malaysia (MINT), Bangi, 43000 Kajang, Selangor
2Jabatan Geologi, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor
Abstract: The fallout isotope caesium-137 (137CS), a product of thermonuclear weapon tests, has been distributed globally and become part of the world ecosystem. For the last 25 years of research, the fallout radionuclide 137CS has been used as an indicator of soil erosion and sediment deposition status. The fallout radionuclide 137CS reached the earth surface primarily in association with precipitation. On reaching the earth surface, 137CS has become firmly adsorbed to surface soils particularly clay minerals. Fallout from atmospheric weapons testing during the 1950s to 1970s has labelled soil materials, so the sites with no net soil loss should have 137CS inventories that reflect the amount of 137CS fallout. The level of 137CS at an undisturbed site should provide a reference value for assessing the degree of erosion and deposition within the area, where sites with less than the reference value can be considered eroded, and sites with more than the reference value can be regarded as depositional. This paper will highlight the advantages and detail information concerning the 137CS technique.