Radiological assessment of NORMs resulting from petroleum industry, Idku coastal area, Egypt

Abstract Naturally occurring radioactive materials (NORMs) are often associated with oil and gas production wastes, where their concentrations may be enhanced by industrial activities. This study assessed potential radiological impacts at the Idku coastal area, which hosts the onshore gas processing facilities of the West Delta Deep Marine (WDDM) field. Samples of sludge, produced sand, and produced water were collected from processing facilities, along with soil, sediments, plants, and water from surrounding environments. Gamma spectrometry (HPGe) was used to determine activity concentrations of radionuclides from the 238 U and 232 Th series and 40 K, and standard radiological hazard indices were calculated and compared with international guidelines. The results indicate that activity concentrations in waste samples ranged from 10–122 Bq/kg for 226 Ra, 4–145 Bq/kg for 232 Th, and 138–529 Bq/kg for 40 K, with the highest values observed in produced sand and sludge from processing units such as slug catchers and sand removal packages. The absorbed dose rate ranged from 7 to 164 nGy/h (average: 51 nGy/h), while the annual effective dose equivalent varied between 0.01 and 0.20 mSv/y (mean: 0.06 mSv/y). Radium equivalent activity ranged from 14 to 366 Bq/kg, remaining below the recommended limit of 370 Bq/kg. Overall, all radiological parameters were within internationally recommended limits, indicating minimal risk to workers and the surrounding environment. These findings emphasize the importance of continuous monitoring and the implementation of preventive measures to maintain exposures as low as reasonably achievable (ALARA), while supporting effective environmental management strategies.