Evaluation of natural radioactivity content in high-volume surface water samples along the northern coast of Oman Sea using portable high-resolution gamma-ray spectrometry

•In this study, distribution of radionuclides in surface waters of Oman Sea has been assessed.•The water samples from 36 coastal and near shore locations were collected for analysis.•High volume surface water samples were analyzed using a Portable HPGe detector.•The activity contents are below limit values and there was no radiological risk.•This research aims to establish baseline map of radioactivity in northern coast of Oman Sea.

Portable high-resolution gamma-ray spectrometry was carried out to determine the natural radioactivity levels in high volume surface water samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz strait to Goatr seaport, for the first time. The water samples from 36 coastal and near shore locations were collected for analysis. Analyses on the samples collected were carried out to determine 226Ra, 232Th and 40K contents. The concentration of 226Ra, 232Th and 40K in surface water samples ranged between 2.19 and 2.82 Bq/L, 1.66–2.17 Bq/L and 132.6–148.87 Bq/L, respectively. The activity profile of radionuclides shows low activity across the study area. The study also examined some radiation hazard indices. The external hazard index was found to be less than 1, indicating a low dose. The results of measurements will serve as background reference level for Oman Sea coastlines.