168 THE SHORTER-TERM BIOLOGICAL HAZARDS OF A FALLOUT FIELD withits 22-hour half-life in some of the samples. This suggests that an appreciable amount of a tion rather than proceeding through the food cycle. Wl In looking for strontium-90 in these samples, we found a maximum value for any one sample of 2.3 disintegrations per minute. However, the everage value of strontivm-90 in the speci- ' i mens collected prior to the test period was 0.09 i disintegrations per minute per 24-hour urine specimen. an £ 234 i160 a 3 120 x= %; 100 & so a % 60 4 = 40 a il 265 iso > 140 activity measurably increased during the inter- bie 2 Ze S 20 z 0 wk # — 10,000} _, wi | t 1 it SHOT# 3 4 6,7 8 ( 8 Oo o T T *>40,000L. = Ge tso00lL. x bz a= 30000] 60 40 20 0 z = 5 a° wee | 2 38 SHOT# | 2 3 4 4 5 §&§ 6 67 89 z F IO) 8 9 t2 0 iH 13 13 14 14 12 Qo 22 FEB. x 5 1 1S 1. 220 «29 | FEB. MAR. APR, Fraure 3.—-Camp Mercury, Nevada. MAY Ht 5 2 APR. MAR. Fraurs 4.—- Tinker Air Force Base. val between Operations Teapot and Redwing. This increase is in part due to foreign weapon tests. In the United States, the average level of iodine-131 excretion during Operation Red- | 169 = 3 AV. DPM L'5! PER 24 HOUR URINE SPECIMEN 1 F 4 o fo] f the samples, Theiodine activity here was corrected to shot time rather than to collection time as is the case for the other graphs. The strontium data could only be obtained by pooling mauy individual specimens. The yttrium-90 daughter separation and counting procedures used were identical with those of the Chicago Sunshine Laboratory. in conclusion we can report that strontium-90 iodme-131 with the strontium-90 activity in the radioiodine enters the body through inhala- pot, = aa o i EXCRETION OF RADIOACTIVE FISSION FRAGMENTS BY MAN Figure 7 shows an attempt to correlate the off Lh] 26 3 19 MAY 7 24 wing is not. markedly different from the level observed during Teapot. Specific data from the Redwing period will be available in a forthcoming report.