Abstract
This study investigates the levels of Naturally Occurring Radioactive Materials (NORM) in produced water and oil-field equipment at NA/100 and BD/200 stations in Libya. The research quantifies radioactivity concentrations and NORM levels using specialized geophysical instruments, including a Gamma Ray Spectrometer model RS 320 and a Gamma Ray Dose Meter model Automess 6150-AD 2. Field surveys were conducted, and five samples (three sludge and two produced water) were sampled from various locations within the area, such as production separators, storage tanks, dehydrators, wash tanks, surge tanks, and pits. These samples were analyzed using laboratory High Purity Germanium (HPGe) detector to determine activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K. The findings reveal significantly elevated levels of NORM in both produced water and sludge samples, as well as high dose rates in certain areas of the oil-field equipment. For instance, the Low Pressure Production Separator C-021 at BD/200 station showed a dose rate of 15.2 µSv/h and a total count of 61246 C.P.S, while the Dehydrator T-031 recorded 8.22 µSv/h and 61800 C.P.S. Analysis of produced water samples indicated ²²⁶Ra concentrations exceeding the Canadian Fluid Control guidelines of 5 Bq/L. Sludge samples, particularly S3 from BD/200, exhibited extremely high concentrations, with ²²⁶Ra at 15500 Bq/kg and ²³²Th at 24800 Bq/kg, far surpassing international exempt values for radioactive waste management. The calculated radium equivalent dose (Raeq), gamma absorbed dose rate (D), hazard index (Hex), and annual effective dose rate (AEDE) for all samples were substantially higher than worldwide averages, with some hazard index values being 10 to 14 times greater than the recommended limit of ≤1. These results show a significant radiological hazard, primarily due to the accumulation of NORM, posing environmental and occupational safety concerns in the Libyan oil and gas industry.