Radionuclides levels were determined in indigenous and transplanted mussels (Mytilus galloprovincialis) collected from Turkish marine environment. Radioactivity concentrations of Cs-137, K-40, Ra-226, Ra-228, (210)po and Pb-210 were determined in the soft tissues of the mussel samples collected in Bosphorus Strait, Coasts of Black Sea, Marmara Sea and Aegean Sea. Mussel transplantation was carried out by using mussel cages in Levantine Sea coast since M. galloprovincialis did not naturally adapt along the coast. The average activity concentrations of Cs-137, K-40, Ra-226, Ra-228, Po-210 and Pb-210 in the coastline of Turkey were found to be 0.7 +/- 0.1, 469 +/- 24, 0.9 +/- 0.1, 1.0 +/- 0.1 +/- 122 +/- 4 and 10.9 +/- 0.9 Bq kg(-1) in dry weight (dw), respectively. The average of Po-210/Pb-210 ratio was found to be similar to 14. Total annual effective Po-210 dose was calculated to be in the range of 0.25-3.30 mu Sv due to mussel consumption. Radioactivity and dose levels were compared with those of similar studies carried out in Mediterranean countries. (c) 2013 Elsevier Ltd. All rights reserved.