Environmental Radiological Assessment of Natural Radioactivity Around Al-Fatai’h Cement Plant in Derna, Libya

Abstract

Naturally occurring radioactive materials (NORM) in the environment originate mainly from primordial radionuclides associated with the uranium- (²³⁸U) and thorium- (²³²Th) decay series, in addition to naturally occurring potassium- (⁴⁰K) present in geological formations and soils. Artificial radionuclides such as Cesium-137 (¹³⁷Cs) and Cobalt-60 (⁶⁰Co) may also be detected in soils, food products, and building materials as a result of radioactive fallout and anthropogenic activities. This study presents the results of a field investigation of natural background radiation levels in agricultural and residential areas surrounding the Al-Fatai’h Cement Plant in Derna , Libya , the surveyed area extended from the coastal highway bridge through the dry valley adjacent to the road leading to the cement plant, up to the satellite district area The study also included raw material quarries, storage hangars, crushers, silos, and residential areas for plant staff. A total of 190 environmental and industrial samples were collected and analyzed using direct gamma-ray spectrometry with a High-Purity Germanium (HPGe) detector. The results showed relatively similar average activity concentrations of radionuclides within each location, with generally low overall natural radiation levels despite geological variations. However, elevated concentrations of Potassium-40 were observed across most sampling sites. This study evaluates the natural radioactivity levels of Potassium-40; Thorium-232; Radium-226 in different locations. The absorbed dose rate (D) and annual effective dose (AED) were calculated using standard radiological conversion factors. The results showed that the absorbed dose rate (D) ranged from 11.92 to 28.16 nGy/h, while the annual effective dose (AED) ranged from 0.015 to 0.035 mSv/y, with mean values of 20.79 nGy/h and 0.026 mSv/y, respectively. These values are lower than the worldwide average values reported by UNSCEAR (59 nGy/h for D and 0.07 mSv/y for AED), indicating that the studied area does not present significant radiological risk. Higher values were observed in mining and industrial-related locations such as Southern Raw Material Processing Area and Crusher & Storage, which may be attributed to elevated concentrations of natural radionuclides in these areas. Overall, all measured values remain within internationally recommended radiological limits, suggesting that the area is radiologically safe for public exposure.