RADIONUCLIDE CONCENTRATIONS IN WHITE STURGEONS FROM THE HANFORD REACH OF THE COLUMBIA RIVER

We summarized radionuclide concentrations in white sturgeons Acipenser transmontanus from the Columbia River during a period when several plutonium-production reactors were operating at the Hanford Site in Washington State and compared these values to those measured several years after reactor shutdown. Studies conducted in the Hanford Reach of the Columbia River during 1953-1955 indicated that high concentrations of radionuclides (as total beta) were present in some internal organs and on the external surface of white sturgeons. Average concentrations were about 1,480 Bq/kg for liver and kidney and exceeded 2,200 Bq/kg for fins and scutes. The principal radionuclides in the tissues of white sturgeons from the Hanford Reach during 1963-1967, the peak reactor operation interval, were P-32 Zn-65, and Cr-51. Average concentrations of P-32 in muscle ranged from 925 to 2,109 Bq/kg and were typically two to seven times greater than Zn-65. Average concentrations of radionuclides were usually in the order of gut contents >> carcass > muscle. Studies from 1989 to 1990 showed that radionuclide concentrations had decreased dramatically in white sturgeon tissue since the time of reactor operation. Maximum concentrations for artificial radionuclides (Sr-90, Co-60, Cs-137) in muscle and cartilage of white sturgeons in the Columbia River had declined to less than 4 Bq/kg. Formerly abundant radionuclides, including P-32, Zn-65, and Cr=51, could not be detected in recent tissue samples. Further, radionuclide tissue burden in populations of sturgeons from the Hanford Reach and the upstream or downstream reference locations did not differ significantly.