lo. Introduction soile The first is to determine the activity per unit area as a measure of cumulative fallout at a specific location. | Soeee raekdelagree eageenpaeimecne Son ee esa,+rogerepee There are two main purposes in the measurement of strontium-90 in The second is to relate the ‘availablet strontium-90 in the soil to its uptake by plants and eventually animals, In regard to the first point, it is generally accepted that for the majority of soils collected for fallout documentation, the strontium-90 is in a form which can be solubilized by leaching with 6 normal hydrochloric acid at room temperature, Some evidence is presented to verify this assumption and a comparison is made with the strontium-90 found by dis-~ solving the soil sample completely after fusion with sodium carbonate. In ee Te! the case of soils collected so close to a weapons testing area that the 7k fallout particles are siliceous in nature (as would be the case at the Nevada Proving Grounds), it is doubtful whether 6 molar hydrochloric acid — These soils are only used for onesite fallout «ik GRIT CARNEpacity SoS20 RS open ati Ane eee cre will have much effect. (2) determination and consequently this would be considered a very special type of sample. The use of 6 normal hydrochloric acid was established as a result of experiments run on two soil samples collected in Hiroshima, Japan in 1954. Several concentrations of mineral acid up to 6 molar in concentration as well as one molar ammonium acetate were used as leaching This data is presented in Table le ener reagents, cae Because of the dynamic nature of the Strontium Program, it was necessary initially to develop procedures within a relatively short period (1) G. Welford, HASL, Private Communication. ~ es a s . L S sy Oe, & cy . “Ay ~~ ae a ay . . ‘ ~~ aS SR es * * . oS MaRS OS = | & - . ON meurmurewanenmes ~~ RDS CT SOE, CEee Se Ry ey, A ae = «7 . . OSS ay AT