Environmental monitoring in the vicinity of the Savannah River Plant. Annual report for 1975

The concentration of radioactivity added by the Savannah River Plant to its environs during 1975 was, for the most part, too small to be distinguished from natural background radiation and fallout from worldwide nuclear weapons tests. Beta activity in particulate air filters was about one-half of the 1974 level and was due entirely to global fallout. An accidental release of tritium to the atmosphere occurred in a production facility on December 31, 1975. Monitoring teams were deployed along the estimated puff trajectory immediately following the release. Monitoring extended from the production facility to the Atlantic Ocean north of Charleston, SC. Environmental sample concentrations of tritium oxide were all within normal ranges. The low concentrations of tritium measured in environmental samples around the plantsite were of no health significance. Tritium, cesium-137, and strontium-90 were the only radionuclides of plant origin detectable in river water by routine analyses. None of these had an average concentration exceeding 0.2 percent of the Concentration Guide in river water samples 8 miles downstream from the plant. Monitoring in an offsite swamp immediately below the SRP boundary has shown radioactivity (primarily cesium-137) above the natural background level in soil and vegetation. Only one-third of a five-square-mile swamp, which is largely uninhabited and inaccessible, bordering the Savannah River and downstream from SRP is affected. No restrictions on use of the swamp are considered warranted nor are remedial actions needed. Concentrations of radioactivity in vegetation and soil were, in most instances, lower than those reported in 1974. During 1975 the average dose from atmospheric releases of radioactive materials from SRP was calculated to be 0.66 millirem (mrem) at the plant perimeter