en Pao a ail Ria CEEhTER = 2ol feevensenepamntitapen natal RAMI anti “ a 2o Experimental Sampling Method wn Most of the soils for fallout documentation and uptake studies are collected by Dre Lo T. Alexander cf the United States Department of non Agriculture. A description of the sampling procedure is given in e - section 6.1 of the Appendix. Preparation of the Sample - . 2o2 j The total soil sample is air-dried or placed in a 100°C oven crushed, including rocks and vegetative material, to an aggregate size fine enough to be biended efficiently. _ . The entire semple is then ground and | for about 12 hours, then weighed, 2o3 Extraction and Separation Strontium carrier (200 milligrams) and strontium=-85 tracer (about 500,000 d/m) are added to a weighed sample aliquot (500 grams). ° The aliquot is stirred with 6 M hydrochloric acid (1 liter) at room temperature for approximately 40 minutes and the extract is filtered and evaporated to a small volume. leached organic material. Nitric acid is added to decompose the After evaporation, most of the leached silica is dehydrated and is removed by filtration. An oxalate precipitation is carried out at pH 5.5 to precipitate the alkaline earths and leave iron in solution. Successive fuming nitric acid separations are performed until essentially all of the calcium is separsted fecn the strontium and ee 7 . om oe a ~~S ¢ “eh ye RS, ta PS =. ~ s= * “aR. recess Cc aera 5 om . . > ~ Ay . & =, . Sey A at Sey, . RIE Etat or ap ar 71 en ce + * a Hg ir a, , . =e = : 6 . ~ ™ ey. os Be . se Merk, = * Sou OTE oe oat, “y . me Loft} ASTR ORS Teg TR ta ves oo," 7 my ee . . ; . =~, no . : . . . * . . - : 3 Eg kN = . , “me sO SR OSES TY 8 1 fF _ otete,