Chernobyl radionuclides in shellfish

Radionuclides from the Chernobyl accident arrived at Monaco on 30 April, 1986. A sample of Mytilus galloprovincialis collected six days later showed near-maximum levels of most radionuclides. Monitoring continued for seven months thereafter, peak concentrations being transiently as high as 480 Bq kg⁻¹ (all soft parts, wet weight) for ¹⁰³Ru. Other radionuclides detected included ¹³²Te, ^129mTe, ¹³¹I, ¹⁰⁶Ru, ¹³⁴Cs, ¹³⁷Cs, ^110mAg, ¹⁴⁰Ba, ¹²⁵Sb, ⁹⁵Nb and ¹⁴¹Ce. Biological half-lives for elimination in this environment were generally around 10 days or longer and most elimination curves contained a number of components. Radionuclide contents of the mussels were predicted quite accurately from concentrations observed on air filters collected simultaneously, but were not satisfactorily explained relative to total radionuclide concentrations in the seawater even three days after peak air filter activities. The use of concentration factors from the literature did not improve the latter predictions. This suggests that the radionuclides were absorbed very rapidly from the fallout particles, rather than from radionuclides first solubilised from particles. Patella lusitanica specimens contained activities about 20–50 times higher than those in the mussels.