Off-site environmental monitoring report for the Nevada Test Site and other test areas used for underground nuclear detonations, January--December 1976

During 1976, the monitoring of gamma radiation levels in the environs of the Nevada Test Site (NTS) was continued through the use of an off-site network of radiation dosimeters and gamma-rate recorders. Concentrations of radionuclides in pertinent environmental media were also continuously or periodically monitored by established air, milk, and water sampling networks. Before each underground nuclear detonation, mobile radiation monitors, equipped with radiation monitoring instruments and sampling equipment, were on standby in off-NTS locations to respond to any accidental release of airborne radioactivity. An airplane was airborne near the test area at detonation time to undertake tracking and sampling of any release which might occur. All radioactivity from the underground nuclear tests was contained except for a total of about 91 curies (Ci) of radioactivity which was reported by ERDA/NV as being released intermittently throughout the year and small undetermined amounts of tritium and 85Kr which slowly seep to the surface from the underground test areas. The only off-NTS indication of this radioactivity was determined from an air sample collected at Death Valley Junction during the period August 24-31. This sample had a 3H in air concentration of 2.7 x 10-11 μCi/ml above background