Risk Assessment for Historic Releases of Radioactivity to the Columbia River

SENES Oak Ridge, Inc., described and demonstrated an independent, scientifically defensible methodology for estimation of exposures and organ doses for individuals exposed to radionuclides released to the environment from the Hanford Reservation. In addition to exposures and organ doses, the methodology included estimation of the excess lifetime risk of developing a radiogenic cancer, the relative risk, and the probability that existing disease was caused by the exposure. The method addressed atmospheric releases of I-131, releases of a number of radionuclides to the Columbia River, and combined exposures to both sources of Hanford radionuclides. All known sources of uncertainty were treated explicitly and propagated through the calculations to the estimates of dose, risk, and probability of causation.

Columbia River Pathway Analysis

SENES Oak Ridge, Inc., carried out a reevaluation of dose estimates for exposures to radionuclides released from the Hanford Reservation to the Columbia River for the Agency for Toxic Substances and Disease Registry. Through examination of historical documents and recent summary reports, SENES identified potential sources of bias in the dose estimates prepared during the Hanford Environmental Dose Reconstruction Project. In addition, SENES prepared revised dose estimates and corresponding risk estimates for people consuming fish and waterfowl from the Columbia River. These results were intended for use in establishing the need for medical monitoring in potentially exposed populations.