RADIOLOGICAL STATUS OF THE GROUND-WATER BENEATH THE HANFORD PROJECT JANUARY-DECEMBER 1978

This report is one of a series prepared annually for the Department of Energy, to provide an evaluation of the status of ground-water contamination resulting from Hanford's onsite discharges. Data collected during 1978 describe the movement of major plumes {{beta}{sub t}, {sup 3}H, NO{sub 3}) that respond to the influences of ground-water flow, ionic dispersion and radioactive decay. The total beta plume continues to recede, with the exception of a beta source that is beginning to show up in the 300 Area, a result of minor spills and leaks which have occurred during the operating life of the 300 Area. The tritium plume continues to expand and is mapped as having reached the Columbia River, although its contribution to the river cannot be distinguished from that attributable to atmospheric fallout. The plume now shows much the same configuration as in 1977. The nitrate plume shows general stability relative to its size with concentrations in the vicinity of the 100-H Area continuing to be high as a result of leaks from the evaporation facility. The results of a study to determine the vertical distribution of contaminants in the Hanford ground-water system indicate that the majority of contaminants are stratified in the upper portions of the unconfined aquifer