APPENDIX | HAZARD CALCULATIONS’ PROJECT GABRIEL The following is a summary of the assumptionsof the earlier GABRIEL studies. GABRIEL: November 12, 1949 The number, N, of nominal (20-KT) bombsrequired to reach threshold lethality over a uniform “‘settling area” is given by N= on (X or + )8, D = “threshold lethality” in pg, G = plant uptake and ingestion factor in grams per person per bomb, a = accumulation (and absorption) factor, d = bone-deposition factor. It is believed that the basis for the factors 2 and 8 is to allow the answer to be too small by a factor of 16, or too great by a factor of 4 (an assumptionthatis not too clear in the text). The various assumed values were: D = 10 ug (estimated error: factor of 4), G = SH/AF, where S = pg yield per bomb, H = proportion of strontium in the soil that goes to human consumption per year (or per crop?), A = area ofspread of debris, F = average number of people who derive their food per square mile of arable fand. The earlier GABRIEL reports made the following assumptions: 1 ¢ 90 2. H was assumed to be 10°? on the basis that edible plants take up 1 per (Actually the yield is about 20 gm.) *For corrections to some of these data, refer to the Preface of this report. 69