title: Natural radioactivity and radiological hazard assessment of Egyptian oil ashes.
abstract: Oil fly and boiler ash samples were collected from the four major Egyptian power plants in order to determine their natural radioactivity. Secular equilibrium between (238)U and (232)Th and their decay products is significantly disturbed in oil ash samples. The (226)Ra/(238)U ratios were between 440 and 1993 with an average value of 801, indicating that the concentrations of daughters (226)Ra were very high compared to the parent (238)U in the oil ash samples. While, the average ratios for (210)Pb/(226)Ra in most samples were 1.19 ± 0.05, indicating a secular equilibrium in the (226)Ra-(210)Pb sub series. The natural radioactivity due to (238)U and (232)Th was found to be negligible. While the activity concentrations of (226)Ra ranged from 3205 to 12,320 Bq kg(-1) with an average value of 9284 Bq kg(-1), (210)Pb ranged from 5960 to 13,930 Bq kg(-1) with an average value of 11,513 Bq kg(-1). The results are compared with the reported data from other countries. The average value of radium equivalent activity was 9308 ± 2729 Bq kg(-1), while the external and internal hazard indexes were found to be 25 ± 7 and 50 ± 15, respectively. All the studied radiological parameters were higher than the recommended limit by the IAEA in all ash samples.
authors.affiliation: Production Division, Nuclear Materials Authority, P.O. Box 530, Maadi Kattameya, Cairo, Egypt. Mohammed@zu.edu.eg.
authors.forename: Hesham
authors.initials: H
authors.lastname: Mohammed
authors.affiliation: Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, Egypt.
authors.forename: Sadeek
authors.initials: S
authors.lastname: Sadeek
authors.affiliation: Production Division, Nuclear Materials Authority, P.O. Box 530, Maadi Kattameya, Cairo, Egypt.
authors.forename: Abu Rehab
authors.initials: AR
authors.lastname: Mahmoud
authors.affiliation: Nuclear and Radiological Regulatory Authority, Cairo, Egypt.
authors.forename: Hanan
authors.initials: H
authors.lastname: Diab
authors.affiliation: Production Division, Nuclear Materials Authority, P.O. Box 530, Maadi Kattameya, Cairo, Egypt.
authors.forename: Doaa
authors.initials: D
authors.lastname: Zaky
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D060729:Coal Ash / Q000032:analysis*; D004534:Egypt; D011197:Potassium Radioisotopes / Q000032:analysis; D011210:Power Plants; D011834:Radiation Monitoring; D011883:Radium / Q000032:analysis; D013910:Thorium / Q000032:analysis
chemical_list: D000396:Air Pollutants, Radioactive; D060729:Coal Ash; D011197:Potassium Radioisotopes; D013910:Thorium; D011883:Radium
keywords: Egyptian oil ashes; Lead; Radiation hazard indices; Radioactive disequilibrium; Radium