title: A comparative study of thorium activity in NORM and high background radiation area.
abstract: Several industrial processes are known to enrich naturally occurring radioactive materials (NORM). To assess such processes with respect to their radiological relevance, characteristic parameters describing this enrichment will lead to interesting information useful to UNSCEAR. In case of mineral treatment plants, the high temperatures used in smelting and refining processes lead to high concentrations of (238)U and (232)Th. Also due to thermal power combustion, concentration of U and Th in the fly ash increases manifold. NORM samples were collected from a Thailand mineral treatment plant and Philippine coal-fired thermal power plants for investigation. Some studies are initiated from a high background radiation area near Gopalpur of Orissa state in India. These NORM samples were analysed by gamma-ray spectrometry as well as inductively coupled plasma mass spectrometry. The radioactivity in case of Orissa soil samples is found to be mainly contributed from thorium. This study attempts to evaluate levels of thorium activity in NORM samples.
authors.affiliation: Research Centre for Radiation Protection, National Institute of Radiological Sciences, Inage, Chiba, Japan. sahoo@nirs.go.jp
authors.forename: S K
authors.initials: SK
authors.lastname: Sahoo
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: S
authors.initials: S
authors.lastname: Tokonami
authors.forename: A
authors.initials: A
authors.lastname: Sorimachi
authors.forename: C
authors.initials: C
authors.lastname: Kranrod
authors.forename: M
authors.initials: M
authors.lastname: Janik
authors.forename: M
authors.initials: M
authors.lastname: Hosoda
authors.forename: N M
authors.initials: NM
authors.lastname: Hassan
authors.forename: S
authors.initials: S
authors.lastname: Chanyotha
authors.forename: V K
authors.initials: VK
authors.lastname: Parami
authors.forename: H
authors.initials: H
authors.lastname: Yonehara
authors.forename: R C
authors.initials: RC
authors.lastname: Ramola
mesh_terms: D000396:Air Pollutants, Radioactive; D016902:Air Pollution, Indoor / Q000032:analysis*; D003031:Coal; D004781:Environmental Exposure; D005720:Gamma Rays; D005740:Gases; D005857:Germanium / Q000032:analysis; D007194:India; D013058:Mass Spectrometry / Q000379:methods; D010679:Philippines; D011834:Radiation Monitoring / Q000295:instrumentation*; D011874:Radiometry; D011886:Radon / Q000032:analysis*; D017687:Radon Daughters / Q000032:analysis*; D012306:Risk; D013696:Temperature; D013785:Thailand; D013910:Thorium
chemical_list: D000396:Air Pollutants, Radioactive; D003031:Coal; D005740:Gases; D017687:Radon Daughters; D005857:Germanium; D013910:Thorium; D011886:Radon