Dr. Gordon Dunning slopes of -2.] or greater. ole May 25, 1954 The water sample of highest concen- tration decayed as t~1.7 using the same shot as its sero tine. Sampling will be continued until normal background air soncentrations are obtained,.* tgs ; ar a ba O TL8/loa On tne Sore we ee RIAL Se2. ES 1 SRAM, BL THOMAS L. SHIPMAN, M. B., Health Division Leader