The fate of the main naturally occurring radionuclides in mussels (Mytilus edulis) and their radiological impact on human beings.

A comprehensive study was made on the activity concentrations, concentration factors, and radiation exposure impact of the main naturally occurring radionuclides in blue mussels collected in the Mediterranean Sea. The results showed that the concentrations of the measured radionuclides were site-specific and all detectable in gram-size samples of the soft tissues of the mussels, especially, some activity concentrations can reach as high as 16.8-102 Bq kg for Po, 16.7-66.8 Bq kg for K and 0.602-3.21 Bq kg for Pb. The obtained mean concentration factors in the soft tissues of the mussel samples are 6.30 ± 2.40 for U and U, 4.68 ± 1.73 for U, (2.72 ± 1.73) × 10 for Th and Th, 480 ± 265 for Th, 33.3 ± 13.3 for Ra, 100 ± 52 for Ra and 29.0 ± 14.7 for Ra, (1.22 ± 0.72) × 10 for Po, 517 ± 280 for Pb and 2.57 ± 0.80 for K. The estimated mean committed effective doses of U, U, U, Th, Th, Th, Ra, Ra, Ra, Po, Pb and K to an adult due to mussel ingestion are 0.073 ± 0.027, 0.089 ± 0.035, 0.0030 ± 0.0011, 0.128 ± 0.098, 0.117 ± 0.081, 0.056 ± 0.031, 0.145 ± 0.058, 0.0487 ± 0.0250, 0.395 ± 0.200, 352 ± 209, 6.00 ± 3.25 and 1.74 ± 0.54 μSv a, respectively. Among the elements or nuclides, Po is the dominant dose contributor which contributes 96.9% of total dose fraction, and the relative dose contribution is in the order of Po > Pb > K > radium ≥ thorium ≥ uranium.