A comparison of four aerial radiological surveys of Par Pond and the surrounding area, Savannah River Site, Aiken, South Carolina

A series of gamma radiation surveys was conducted over Par Pond at the Savannah River Site (SRS) in August 1993, October 1991, and August 1992 as part of an effort to monitor the radiological changes around Par Pond as its water level was lowered. The results of an April 1989 survey, which was about one-half the area of those surveys listed above, were used as baseline data for the comparison. Gamma energy spectrum analysis revealed that the only man-made gamma ray emitter detected during the four surveys in the Par Pond area was cesium-137. The comparisons revealed that: (1) significant change in the radiological environment occurred along the Par Pond shoreline as the water levels were lowered, (2) the activity in Lower Three Runs Creek varied slightly as the level/flow rate changed during the pumping process, (3) minor changes occurred in areas adjacent to the Par Pond, and (4) little or no change occurred between surveys in the spatial distribution or kind of sources detected. All changes were directly related to the moisture variations (Par Pond water lowering, rainfall, waterway flow rates) between the survey periods. The distribution, kind, and activity of sources detected beyond the pond bed were consistent between surveys. 60 figs., 14 tabs