INDOOR AND OUTDOOR BACKGROUND EXPOSURE LEVEL ASSESSMENT OF SOME LOCATIONS IN NATIONAL YOUTH SERVICE CORPS ORIENTATION CAMP, KEFFI, NASARAWA STATE, NIGERIA

Background: Human activities have increased the relative concentration of the radionuclides, referred to as the technologically enhanced naturally occurring radioactive materials (TENORMS) in our society. Aim: To assess the indoor and outdoor background exposure level of some selected locations in National Youth Service Corp Orientation camp, Keffi, Nasarawa state, Nigeria. Methodology: A total of ten halls were selected and the exposure rate for four sampling points (two indoor and two outdoor) for each of the hall were measured using a handheld Inspector Alert Nuclear Radiation Monitor. The Radiation Monitor was held at an elevation of 1.0m above ground level and a geographical positioning system (GPS) was used to record the location. The absorbed dose rate, annual effective dose rate, excess lifetime cancer risk and organ doses were calculated. Results: The result obtained are in the range of 0.16 – 0.36 mR/h, 0.016 - 0.026 μSv/h, 0.11- 0.25 mSv/y, and 0.39- 0.88 for ER, ADR, AEDR, and ELCR respectively. The calculated mean organ dose is 0.122, 0.110, 0.131, 0.156, 0.118, 0.087, and 0.129 for lungs, ovaries, bone marrow, testes, kidney, liver, and whole body respectively. Conclusion: The obtained values of AEDR and organ doses are lower than the recommended dose limit by ICRP and UNSCEAR. This indicates that the inhabitant of the orientation camp is safe of radiation hazards. Recommendation: It is recommended that this same study be done at other NYSC camp sites in the country.