Past operations at the Hanford Site 100-N Area reactor resulted in the release of radiological contaminants to the soil column, local groundwater, and ultimately to the near-shore environment of the Columbia River. In September 1997, the Washington State Department of Health (WDOH) and the Hanford Site Surface Environmental Surveillance Project (SESP) initiated a special study of the nearshore vicinity at the Hanford Site's retired 100-N Area reactor. Environmental samples were collected and analyzed for radiological contaminants (3H, %r, and gamma emitters), with both the WDOH and SESP analyzing a portion of the samples. Samples of river water, sediment, riverbank springs, periphyton, milfoil, flying insects, clam shells, and reed canary grass were collected. External exposure rates were also measured for the near-shore environment in the vicinity of the 100-N Area. In addition, samples were collected at background locations above Vernita Bridge. River water samples were collected from five sites that bracketed the %Sr groundwater plume. Both 3H and %Sr were measured above background concentrations for the 100-N Area near-shore river water samples, with the highest 3H concentrations measured at the farthest downstream location and the highest %Sr concentration measured near the center of the "Sr groundwater plume. Transect samples of nearshore water showed that 3H and %Sr concentrations were rapidly diluted by the river. Riverbank spring water contained detectable amounts of 3H and %3r. Concentrations of gamma emitters were below levels of detections for both river water and riverbank spring water. Sediment samples collected near the 100-N Area shoreline had detectable concentrations of 6oCo, %Sr, and I3'Cs; however, 6oCo and wSr were the only radionuclides with concentrations above background. Some biota samples collected at the 100-N Area shoreline had concentrations of 6oCo and I3'Cs above background. In general, the biota results mirrored the localized river water and river sediment concentrations. External exposure rates measured along the shoreline in the vicinity of the 100-N Area ranged h m 2 to 14 pR/h, with the highest rates found along the shoreline nearest to the 1301-N and 1325-N liquid waste disposal facilities. The results fiom this study were used to estimate potential human doses resulting from recreational activity near the 100-N Area shoreline. The estimated doses are small and not expected to be harmful to people engaged in these activities. All estimated doses to aquatic biota were below 1 radday.