This study presents the results of Cs-137 and K-40 radionuclide concentrations in mussel (Mytilus galloprovincialis) samples collected during the period of February-November 2014 from twelve different stations within the border of the eastern Black Sea region of Turkey. Also, these radionuclide concentrations were determined in sea water and sediment samples. The activity concentrations in seawater, sediment and mussel tissue samples were between 1.12-1.69 mBq L-1, 3.26-30.74 and 1.61-3.16 Bq kg(-1) for Cs-137 and 231.41-399.49 mBq L-1, 215.71-450.07 and 286.84-382.16 Bq kg(-1) for K-40, respectively. These values are also in accordance with the concentrations reported for similar regions. Additionally, radiological impact parameters such as daily intake of Cs-137 and K-40, annual committed effective dose and carcinogenic risk due to the consumption of mussel were calculated and compared with the international data. Lifetime cancer risk values are lower than the limit of 10(-3). (C) 2016 Elsevier Ltd. All rights reserved.