%0 Journal Article
%T Gamma Emitting Radionuclides in Soils from Selected Areas in Douala-Bassa Zone, Littoral Region of Cameroon
%A Maurice Moyo Ndontchueng
%A Eric Jilbert Mekongtso Nguelem
%A Augustin Simo
%A Raymond Limen Njinga
%A Gembou Shouop C¨¦bastien Jo£¿l
%J ISRN Spectroscopy
%D 2014
%R 10.1155/2014/245125
%X A study of natural radioactivity levels in some composites of eighteen soil samples selected within Douala-Bassa zone of Littoral Region has been evaluated. The samples were analysed using gamma spectrometry based broad energy germanium detector (BEGe 6350). The activity profile of radionuclide shows low activity across the studied areas. The obtained mean values of 226Ra, 232Th, and 40K in the two campuses were 25.48£¿Bq/kg, 65.96£¿Bq/kg, and 39.14£¿Bq/kg for Campus 1 and 24.50£¿Bq/kg, 66.71£¿Bq/kg, and 28.19£¿Bq/kg for Campus 2, respectively. In terms of health analysis, some radiation health hazard parameters were calculated within the two campuses. The mean values of radium equivalent activity were 122.81£¿Bq/kg and 122.08£¿Bq/kg, absorbed dose rate in air was 99.13£¿nGy/h and 98.18£¿nGy/y, annual outdoor effective dose was 0.12£¿mSv/y and 0.12£¿mSv/y, and external health hazard index was 0.34 and 0.33 in Campus 1 and Campus 2, respectively. These health hazard parameters were seen to be below the safe limit of UNSCEAR 2000 except the absorbed dose rate in air and the annual outdoor effective doses which are relatively high compared to the values of 60£¿nGy/h and 0.07£¿mSv/y. These results reveal no significant radiological health hazards for inhabitance within the study areas. 1. Introduction Gamma radiation emitted from naturally occurring radioisotopes, also called terrestrial background radiation, represents the main source of radiation of the human body. Natural environmental radioactivity and the associated external exposure due to gamma radiation depend primarily on the geological and geographical conditions and appear at different levels in the soils of each region in the world [1, 2]. Only radionuclides with half-lives comparable with the age of the earth or their corresponding decay products existing in terrestrial materials such as 232Th, 238U, and 40K are of great interest. Abnormal occurrences of uranium and its decay products in rocks and soils and thorium in monazite sands are the main sources of high natural background areas that have been identified in several areas of the world [3]. Outdoors exposure to this radiation originates predominantly from the upper 30£¿cm of the soil [1]. According to the literature of natural radioactivity in soil, there is lack of information on natural radioactivity levels in soils from various living sites in Cameroon. Radionuclides in soil generate a significant component of the background radiation exposure to the population [3]. The knowledge of specific activities or concentrations and distributions of the
%U http://www.hindawi.com/journals/isrn.spectroscopy/2014/245125/