title: Natural radioactivity and external dose in the high background radiation area of Lambwe East,Southwestern Kenya.
abstract: Absorbed dose rates around the North and South Ruri hills in Lambwe east, southwestern Kenya were measured using survey meters. The area lies roughly between latitudes 0°30'S and 1°00'S. It is bounded on the east by longitude 34°30'E and on the west by the shores of Lake Victoria and Winnam Gulf. The measured absorbed dose varies from 0.7 to 6.0 µGy h(-1), and the mean is 2.3 µGy h(-1). Assuming an outdoor occupancy factor of 0.4, the corresponding range and mean annual effective doses are 1.7-14.7 and 5.7 mSv, respectively. The average activity concentrations (ACs) of (232)Th, (226)Ra and (40)K in samples of soils and rocks from the area are 1397, 179 and 509 Bq kg(-1), respectively. Values of absorbed dose rates calculated from the ACs are general lower than those obtained from in situ measurements. Possible causes of these discrepancies were discussed in the paper.
authors.affiliation: Department of Physics,  University of Nairobi, PO Box 30197, Nairobi,  Kenya.
authors.forename: S O
authors.initials: SO
authors.lastname: Achola
authors.forename: J P
authors.initials: JP
authors.lastname: Patel
authors.forename: A O
authors.initials: AO
authors.lastname: Mustapha
authors.forename: H K
authors.initials: HK
authors.lastname: Angeyo
mesh_terms: D001417:Background Radiation; D004781:Environmental Exposure / Q000032:analysis*; D007630:Kenya; D011834:Radiation Monitoring / Q000379:methods*; D011868:Radioisotopes / Q000032:analysis*
chemical_list: D011868:Radioisotopes