ee . Jem . 407839 « Radioiodine Leyels'in the U. S. Public Health Service Pasteurized Mili Network from 1963 to 1968 and their Reletionship to Possible Sources p_ | Lester Machta and Kosta Telegadas Environmental Seience Services Administration Silver Spring, Md. 20910 Abstract. Meteorological analysis of the paths of nuclear clouds has been used to assign the source of radioiodine in the milk samples collected in the U. S. Public Health Service Pasteurized Milk Network (PMN). Most of the instances of elevated values between April 1963 and December 1968 are attributed to six atmospheric nuclear explosions in western China. Only |. — . . one of five cratering events at the Nevada Test Site caused elevated values in the PMN milk. Two periods with relatively low concentrations of radio- iodine in milk possess no apparent explanation. By selecting periods with no atmospheric or cratering events, it is argued that at most small amounts of radioiodine in the PMN can be attributed to accidental releases from : underground nuclear tests in tne United States during the period of f analysis. 2 Radiolodine from accidental releases, reactor tests, and cratering events has beendetected in a local raw milk network surrounding the Nevada Test Site. . . Ae ee ane 4 BEST COPY AVAILABLE } 3