Investigation and mapping of natural and artificial radioactivity in sediment samples from Borcka Black Lake, Artvin-Turkey

Abstract

All living creatures in nature are constantly exposed to ionising radiation, which is emitted from natural and artificial radiation sources. For this reason, it is important to monitor the levels of radioactivity in living spaces and visited areas. In this study, natural (U-238, Th-232, K-40) and artificial (Cs-137) radioactivity concentrations in sediment samples taken from Borcka Black Lake located on the Nature Park in Artvin province were determined using a high purity germanium detector (HPGe). It was determined that U-238, Th-232, K-40 and Cs-137 radioisotope concentrations in the sediment samples varied between 8.73 and 26.45, 7.01 and 22.98, 289.92 and 578.98, and 6.26 and 70.96 Bq kg(-1), respectively. Mean radioactivity concentrations were found to be 14.99 +/- 0.89 Bq kg(-1) for U-238, 13.85 +/- 1.10 Bq kg(-1) for Th-232, 473.67 +/- 14.21 Bq kg(-1) for K-40 and 35.06 +/- 0.96 Bq kg(-1) for Cs-137. In order to evaluate the radiological hazards, radium equivalent activity, external hazard index, absorbed dose rate in the air, the annual effective dose rate and excess life time cancer risk were calculated and compared with the values recommended by international organisations. As a result, it has been shown with this study that the radioactivity caused by the examined radioisotopes will not pose any health risk for the visitors of Borcka Black Lake