-3- Tete rmnceMe ran tee ee Some possibilities of an attack of this sort on the problem of ar?? accumulation in the soil can be shown from ae few pleces of data that are presently available.. ~% _ As Calculation of ‘soit/atx ratios of RaD at eshington, D.C. . (asta from NRL Report 4069): _ mae wt Someae _ RaD inrainvweter =+ 20aja (June-Rovember 1950) oes _, Reinfeld at Washington = 43"/year a cea ee eo ae ~ em, S 27 gallons/sq. ft. -'+MotelRaD deposited _¥ 540 d/m/sq. ft. wast ~ ~ If this rete of deposition ie continued for |a number of years02 oy), en AGA} equilibrius velue of RaD in the soil wild be attained as given by the relation: ft. “nan (Wa/re®) »BB40 alee, . Celera naoh er Air concentration of RaD 7 & x 106+ a/m/ou. ft. Soil/air ratio =. eT 10", - 4x10! ... Bs Whether ratios of any great accuracy can be obtained will be dependent Gn finding suitable soil samples of low radium content. _ 7 _ Fa content of "average" rock “= lx yo~+# e/g of soil (varies from~5 x 10722 for some granites to as low as 0.12 x 107° for certain chalks, etc.) Re = Rn = RaD activity «1x 1071? C/g x 2.2x 10°? d/mn/C . = 2.2 d/m gram of soil Yor a1 ft. square soil sample 1 inch deep there are 2360 ec of soil or ~ 6000 grams of soil , ‘ _ ©- Top inch of “normal” soil would contain 13,000 d/m of RaD assuming no gain \ or Joss of Rn and its decay products (range 65,000 to 1600) -Ghe radioactivity profile of the soil at Washington can thus be depicted echpatically as: N