Water and air concentration data are reported in disintegrations per minute of Sr70 per unit volumes. A description of the chemical procedures and the absolute counting method employed by the Chicago Sunshine Project group has been reported, 2. &E, A. Martell, "The Chicago Sunshine Method; Absolute Assay of Sr70 in Biological Materials, Soils, Waters and Air Filters", AECUW3262, May 1956, A considerable portion of the data presented in this report has been discussed by We F. Libby,2s4 Some of the data of Bulletins 11 and 12 are 3, W. F. Libby, "Radioactive Strontium Fallout", Proc. Nat. Acad, Sci, he W, F. Libby, "Current Research Findings on Radioactive Fallout", Speech before AAAS, Washington, D.C., October 12, 1956. 42, 365 (1936). summarized in graphical or tabular form and are briefly discussed in the following section of this report.