Natural and artificial radioactive pollution in sediment and soil samples of the Bosphorus, Istanbul

This study focused on the determination of natural (²³⁸U, ²³²Th, and ⁴⁰K) and artificial (¹³⁷Cs) radionuclide concentrations both in 55 sediment samples collected from various depths in the Bosphorus and 5 soil samples from the coastline of the Bosphorus, Istanbul, using gamma-ray spectrometry with an HPGe detector. The mean activity concentrations of natural ²³⁸U, ²³²Th, and ⁴⁰K and anthropogenic ¹³⁷Cs were determined to be 11.41 ± 0.21 Bq kg^-1, 6.87 ± 0.16 Bq kg^-1, 369.61 ± 3.41 Bq kg^-1, and 6.54 ± 0.11 Bq kg^-1, respectively, in the sediment samples. The average activity concentrations of ²³⁸U, ²³²Th, ⁴⁰K, and ¹³⁷Cs radionuclides in the soil samples were also measured to be 11.65 ± 0.18 Bq kg^-1, 9.55 ± 0.15 Bq kg^-1, 369.43 ± 3.09 Bq kg^-1, and 4.57 ± 0.09 Bq kg^-1, respectively. Radiological contour maps based on the activity concentrations of natural and artificial radionuclides in the sediment samples for the Bosphorus, Istanbul, were created. The total annual effective doses due to soil samples were calculated to be 34.58 μSv y^-1.