Assessment of the natural radioactivity in the coastal areas of Lagos, Nigeria

Abstract

The concentrations of natural radionuclides, namely 40K, 238U and 232Th, in the surface soils around the coastal lands of Lagos, were measured using a highly sensitive γ-ray spectrometric system coupled to a computerized ACCUSPEC multichannel analyzer system. 146 samples from 22 different locations were analyzed and the mean radioactivity concentrations obtained were (0.2293 ± 0.0277), (0.0200 ± 0.0054) and (0.0524 ± 0.0042) KBqkg-1 for 40K, 238U and 232Th respectively. The mean absorbed dose rate, the mean annual effective dose equivalent and the collective effective dose equivalent for these coastal areas were assessed to be (52.23 ± 0.124) nGyh-1, 64.055 µSvy-I and 1.8468 x 102 man.Sv.y-1 respectively. Exposure to these low doses, over a long period of time, can constitute health hazard, especially inside dwellings where sand taken from these areas are used as building materials.


(Botswana Journal of Technology: 2003 12(1): 53-57)