Abstract

A study to assess the outdoor Background Ionizing Radiation (BIR) levels in Emene Industrial Layout of Enugu State, Nigeria has been conducted. An in-situ measurement of BIR exposure rate in mRh-1 for 30 locations was done using a well calibrated portable GQ GMC-320 PLUS nuclear radiation detector at an elevation of 1.0 m above ground level with a geographical positioning system (GPS) for geographical location. The measured BIR exposure rates were used to evaluate the radiological health hazards and radiation effective doses to different body organs using well established radiological relations. The obtained values were compared with recommended permissible limits to ascertain the radiological health status of the environment. The mean values of BIR exposure levels (0.015±0.001 mRh-1), absorbed dose rates (126.15±5.10 ηGyh-1) and excess lifetime cancer risk (0.541±0.032×10-3) are higher than their recommended safe limits of 0.013 mRh-1, 84.0 ηGyh-1, 0.29×10-3 respectively as recommended by ICRP and UNSCEAR. The mean annual effective dose equivalent (0.155±0.006 mSvy-1) is within recommended permissible limits of 1.00 mSvy-1 for general public exposure. Also, the effective doses to different body organs are all below the recommended limits of 1.0 mSvy-1. Generally, the study shows that Emene Industrial Layout is radiologically contaminated due to industrial activities taking place. However, the contamination does not constitute any immediate radiological health effect on resident of the area but there is the potential for long-term health hazards in the future such as cancer due to accumulated doses.

Key words: BIR exposure level, effective dose, industrial activities, Emene Industrial Layout.