ea yO Aye ACKNOWLEDGMENTS 1. To Dr. Lyle T. Alexander, Chief, Soil Survey Labora- tory, U. S. Department of Agriculture, for collecting and arranging for many. of the samples reported here. 2. To the members of the Analytical Branch Staff who performed most of the analyses reported, particularly Charles fF, Baxter, Ira Cohen, William R. Collins jr., Gerald H. Hamada, Helen W. Keller, John J. Kelly, Americo Rodriguez, and Bernard Stern. 3. To Isotopes Incorporated and Nuclear Science and Engineering Corporation who performed certain analyses under con- tract to the Atomic Inergy Commission. Such results are marked (I) end (N) in the tables of data. hk, To Mr. Erie W. Mood of the New Haven Department of Health for supplying dustfall samples collected by his organization. > te ea OSS :