Measurement of environmental radiation levels and contour map development for the northern zone of Adamawa state, Nigeria
The mean environmental background radiation for four local government areas namely. Mubi North, Mubi South, Michika and Madagali, all in the northern zone of Adamawa State, Nigeria was measured using a Radiation Alert Monitor 4 solid state G.M. tube. From the data obtained the exposure rate, absorbed dose and whole body equivalent dose were calculated. The whole body equivalent dose values range from 1.12±0.04 mSv/yr for Nyibanga to 3.06±0.04 mSv/yr for Ribawa. These values are all above the ICRP recommended maximum permissible level (MPL) of 1.0mSv/yr. for the general population, making the entire area a zone of relative high activity. The mean activity data was utilized to generate a background radiation contour map of the area using the “SurGe” mapping and gridding software. The map provides a non-discontinuous picture of the activity in the area.
Keywords: Activity, Exposure rate, Absorbed dose, Whole body equivalent dose, Contour map.