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-1 for 210Po, 16.7-66.8 Bq kg-1 for 40K and 0.602-3.21 Bq kg-1 for 210Pb. The obtained mean concentration factors in the soft tissues of the mussel samples are 6.30 ± 2.40 for 238U and 234U, 4.68 ± 1.73 for 235U, (2.72 ± 1.73) × 104 for 232Th and 230Th, 480 ± 265 for 228Th, 33.3 ± 13.3 for 226Ra, 100 ± 52 for 224Ra and 29.0 ± 14.7 for 228Ra, (1.22 ± 0.72) × 104 for 210Po, 517 ± 280 for 210Pb and 2.57 ± 0.80 for 40K. The estimated mean committed effective doses of 238U, 234U, 235U, 232Th, 230Th, 228Th, 226Ra, 224Ra, 228Ra, 210Po, 210Pb and 40K 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-1, respectively. Among the elements or nuclides, 210Po is the dominant dose contributor which contributes 96.9% of total dose fraction, and the relative dose contribution is in the order of 210Po > 210Pb > 40K > radium ≥ thorium ≥ uranium.