Measurement of Background Radiation Levels in Selected Industrial Areas of Port Harcourt, Rivers State

Background: Industrial activities including petroleum refining and gas flaring in Port Harcourt, South South Nigeria, raise concerns about elevated environmental radiation levels. Systematic baseline radiation monitoring is essential for public health protection. Aim: This study measured background radiation levels in selected industrial and residential areas of Port Harcourt, Rivers State. Methods: A Radalert 100 Geiger-Muller counter was used to measure gamma radiation dose rates at 45 sampling points across five industrial and five residential zones. Measurements were taken at 1 metre above ground level at three times daily over 14 days. Results: Mean radiation dose rates ranged from 0.08 to 0.34 microsieverts per hour across all sampling points. Industrial zones recorded significantly higher mean values (0.28 microSv/h) compared with residential zones (0.11 microSv/h). However, all measured values remained below the ICRP public dose limit of 1 mSv per year derived from natural background. Conclusion: Background radiation levels in Port Harcourt industrial areas are elevated relative to residential zones but remain within internationally accepted safety limits. Long-term continuous monitoring programmes are recommended to detect trends. Keywords: background radiation, Geiger-Muller counter, industrial areas, Port Harcourt, environmental monitoring.