Measurement of Background Ionizing Radiation at Samaru College of Agriculture, Division of Agricultural Colleges, Ahmadu Bello University, Zaria

Background ionizing radiation (BIR) is a significant contributor to human radiation exposure, with levels influenced by geological, environmental, and anthropogenic factors. Continuous assessment of BIR in learning environments is essential for safeguarding public health, as students and staff spend considerable time indoors, particularly in hostels, classrooms, and offices. Against this backdrop, an in-situ measurement of background ionizing radiation was carried out in twelve (12) sections of Samaru College of Agriculture, Division of Agricultural Colleges, Ahmadu Bello University (ABU), Zaria, Kaduna State, Nigeria. The study assessed indoor and outdoor background ionizing radiation (BIR) levels using a calibrated portable handheld gamma survey meter. The indoor BIR ranged from 0.119 to 0.186 µSv/hr, with an average value of 0.155 ± 0.06 µSv/hr and outdoor BIR ranged from 0.114 to 0.204 µSv/hr, with an average value of 0.144 ± 0.04 µSv/hr. Both indoor and outdoor average values exceeded the global indoor and outdoor averages of 0.013 µSv/hr and 0.015 µSv/hr, respectively (ICRP, 2007). The total annual effective dose for indoor measurements was 0.739 mSv/yr, and for outdoor measurements given as 0.190 mSv/yr, which were all below the maximum permissible limit of 1 mSv/yr (UNSCEAR, 2000). The average ELCR for indoor and outdoor measurement was 0.002 and 0.0038 respectively. These values were lower than the world recommended threshold of 0.29 × 10⁻³ (UNSCEAR, 2000). Although the observed radiation levels were generally within global safety limits, slightly elevated ELCR values in residential zones indicate a potential long-term health concern. These findings provide baseline data for radiological monitoring and contribute to environmental health risk assessments in academic institutions.