Bivalves (Mytilus edulis, Mytilus californianus, Crassostrea virginica
and Ostrea equestris) were collected once per year during 1976, 1977, and
1978 along the United States coast and analyzed for 239,240 Pu, 241Am and
137Cs as part of the U. S. Mussel Watch program. Monthly samples were
collected during 1976-1980 from Narragansett Bay, Rhode Island and Bodega
Head, California and analyzed for 239,240 Pu, 241Am , and 137Cs.
There is no evidence in the data for systematic regional or local elevated
concentrations of radionuclides as a result of releases from the
nuclear fuel cycle. Elevated concentrations of 239,240 Pu in mussels
from the central California coast are due to uptake from upwelled water
fed by North Pacific water which has elevated 239,240 Pu from input of
nuclear weapons test fallout.
Monthly fluctuations in radionuclide concentrations in the Narragansett
Bay mussels appear to be primarily influenced by spawning. The
slight monthly fluctuations in the radionuclide concentrations for the
Bodega Head mussels are less coherent from year to year compared to Narragansett Bay although 239,240 Pu may be influenced by upwelling season.
Limited data on transplants of mussels as well as mussel data from
the Ebro estuary on the Spanish coast and from the Irish Sea are also