Determination of natural radioactivity levels of beach sand samples in the black sea coast of Kocaeli (Turkey)

• The radiation hazard parameters were evaluated in beach sands of Black Sea coast of Kocaeli, Turkey.
• The level of the natural radioactivity in Kocaeli Black Sea beaches does not exceed the norm.
• The obtained results will serve as a baseline data in future for assessing the radiation exposure.

The natural radioactivity due to the presence of 238U, 232Th, 40K and the artificial radioactivity due to 137Cs in beach sand samples from the Black Sea coast of Kocaeli (Turkey) have been measured by a gamma ray spectroscopy. Activity concentrations of 238U, 232Th, 40K and 137Cs varied in the ranges from 4.41±0.03 to 14.04±0.04, from 2.62±0.02 to 16.55±0.03, from 11.60±0.25 to 513.32±3.44 and from 0.56±0.02 to 5.43±0.03 Bq kg−1, respectively. The gamma dose rate in air due to 238U, 232Th and 40K in the samples has been estimated to be in the range between 4.10 and 36.80 nGy h−1. The radium equivalent activity values of all sand samples are calculated and found lower than the world limit of 370 Bq kg−1. In addition, the calculated values of external hazard indexes varied from 0.0244 to 0.2019, and are lower than unity.