Radionuclides in fishes and mussels from the Farallon Islands Nuclear Waste Dump Site, California

The Farallon Islands Nuclear Waste Dump Site (FINWDS), approximately 30 miles west of San Francisco, California, received at least 500 TBq encapsulated in more than 47,500 containers from approximately 1945 to 1970. During several seasons in 1986/87 deep-sea bottom feeding fishes (Dover sole = Microstomus pacificus; sablefish = Anoplopoma fimbria; thornyheads = Sebastolobus spp.) and intertidal mussels (Mytilus californianus) were collected from the vicinity of the FINWDS and from comparable depths at a reference site near Point Arena, CA. Tissues were analyzed for several radionuclides (137Cs, 238Pu, 239+240Pu, and 241Am). Radionuclide concentrations for fish mussel tissue ranged from non-detectable to 4,340 mBq kg-1 wet weight, with the following means for Farallon fishes: 137Cs = 1,110 mBq kg-1; 238Pu = 390 mBq kg-1; 239+240Pu = 130 mBq kg-1; and 241Am = 1,350 mBq kg-1. There were no statistically significant differences in the radionuclide concentrations observed in samples from the Farallon Islands compared to reference samples from Point Arena, CA. Concentrations of both 238Pu and 241Am in fish tissues (from both sites) were notably higher than those reported in literature from any other sites worldwide, including potentially contaminated sites. Concentrations of 239+240Pu from both sites were typical of low values found at some contaminated sites worldwide. These results show ∼ 10 times higher concentrations of 239+240Pu and ∼40-50 times higher concentrations of 238Pu than those values reported for identical fish species from 1977 collections at the FINWDS. Radionuclide concentrations were converted to a hypothetical per capita annual radionuclide intake for adults. 51 refs., 5 figs., 3 tabs