[en] This report summarizes progress from 1 January 1983 through 31 December 1983 in research dealing with the behavior of transuranic and other radionuclides in the Columbia River downstream from the Hanford Reservation and in the northeast Pacific Ocean. The work summarized includes: (1) a comparison of the mass-spectrometric determination of Pu in biological samples between Savannah River and Battelle-Northwest; (2) the collection of biological samples from the Columbia River between Bonneville Dam and Ice Harbor Dam on the Snake River; (3) preparation of a manuscript detailing the sedimentation regimes in the lower Columbia River and the Columbia River Estuary; (4) preparation of a manuscript summarizing results to date on the inventories, sources and geochemical behavior of transuranic and other radionuclides in the lower Columbia River; (3) completion of measurements of McNary Reservoir cores for ¹⁵²Eu and ¹⁵⁴Eu; and (6) completion of initial measurements of selected McNary Reservoir sediments to confirm the presence of Ni-63