Determination of Natural Gamma Radioactivity in Sands along the Coastal Regions of Ordu, Giresun and Trabzon

In this study natural gamma radioactivity levels are determined on sands along the coastal regions of Ordu, Giresun and Trabzon. The coast of Ordu, Giresun and Trabzon about 290 km long in investigated to collect 101 sand samples. Natural and artificial radioactivity concentrations of sand samples were measured by using HPGe gamma spectrometry. The average activity concentrations of 238U, 232Th, 40K and 137Cs on sand samples of Ordu, Giresun and Trabzon were found to be 25,40±2,95 Bq/kg, 10,83±2,92 Bq/kg, 673,31±45,31 Bq/kg, and 9,71±1,16 Bq/kg, 21,28±3,22 Bq/kg, 13,72±3,23/kg Bq/kg 530,88±36,64 Bq/kg and 6,42±1,06 Bq/kg, 15,96±1,81 Bq/kg, 7,99±2,39 Bq/kg, 230,94±10,67 Bq/kg and 3,25±0,72 Bq/kg, respectively. The average activity concentrations for these radionuclides were compared with the reported data of other parts of Turkey and other countries. The average absorbed dose rate for Ordu, Giresun and Trabzon were calculated to be 43,53 nGy/h, 38,68 nGy/h and 20,64 nGy/h, respectively. These values are significantly lower than the World averaged value of 60 nGy/h. The external annual effective dose rate concentration in Ordu, Giresun and Trabzon were found to be 0,087 mSv/y, 0,047 mSv/y and 0,025 mSv/y, respectively. This result is much lower than the recommeded limit of 5 mSv/y. The external hazard dose rate for Ordu, Giresun and Trabzon were calculated to be 0,23, 021 and 0,14, respectively. This result is much lower than the recommended limit of 1.0. Key words: Natural Radioactivity, Beach Sand, Annual Effective Dose and External Hazard Dose.