‘ o Bo@ a &s wo se aN] usee Ss s ~ a z 4 2 vy * 2 - ° vo - _ o — °o -——s a _ ow am . Q . Oo o v 7 mw = Bs £> 2 _ # es esis uw * ~~ + OV» bas woe A + << o -—— .2s oaE ~p—~ - @ oem 2 wn ' OQ - _ _ * x — In these trials the solubility of plutonium-238, -239, and americium-241 from the rumen contents of cattle grazing on plutonium contaminated desert vegetation was determined in im vittro bovine pastrointestinal fluids. This study, which is still in progress, was initiated in November 1973 (Barth, 1975; Barth, in press). Americium-241 was first included during the November 5, 1974, trial. * N wn ‘ oS wy . Qo Field-Ingested Transuranics Study ~ wo _— secretion is proportional to the effective dose present. w + Rumen-fistulated cattle were allowed to graze periodically in the inner enclosure and nonfistulated cattle were allowed to graze continually in the outer enclosure of Area 13 of the Nevada Test Site (Smith, 1975}. The inner enclosure directly surrounds the ground zero of a high-explosive detonation of an atomic device during a safety test. The outer enclosure is less heavily contaminated and most of this area fs located a greater distance downwind from ground zero than the inner enclosure. = . _ _ a > = ao uo Ooem~ Yoo: oO hs 8 mw o& ge& ° © ~2og . . a wv LL a ~ K -* — © oe OU-re Cee asoe adapt ao QO o; =. ° _ ~ ” > a — cs aw o fae) Ow 3 = & oO Pe a8 —- os oO. uw w ~ o i + oo wo a — 4 oO — oS **Stanley et al. (1975) . ary o- s= -——, — 4 ee tCalculated from data of Stanley e¢ ai. (1975) » 10.2 x 10-?% times 3.7% = These prediction procedures are valid only when tracer or micro levels of a radionuclide are administered or ingested and the tissue uptake or milk * Ow — 14.8 x 1073% times 3.7% = 5.5 x 107-"%; bone: 3.8 x 10732), (Table 2). 2 aa woe An alternate procedure for the prediction of tissue retention is to calculate the product of the known percentage of the effective dose retained by the tissue times the im vitro solubility of the unknown (liver: . : reser} of the effective dose of plutonium-238 retained by the liver and bone are in close agreement for both forms of plutonium-238. ™~ o ~ x *Explained in text, COMPARISON OF THE THEORETICALLY SOLUBLE PLUTONI UM-238 FROM PLUTONIUM-238 CITRATE AND PLUTONIU M- 238 DIOXIDE RETAINED BY TISSUES TABLE 2. * Samples of whole rumen contents were collected from the fistulated cattle following a 48-hour grazing period. Samples were collected from the nonfistulated cattle at the time of slaughter. Samples of whole rumen contents were added directly to simulated abomasal fluid, The abomasal and intestinal digestion procedures were similar to those described earlier. The entire contents of each flask were separated into solid and liquid fractions by preliminary filtration and centrifugation. The entire solid and liquid fractions were analyzed for plutonium-238, plutonium-239, and americium-241. The behavior of field-ingested plutonium in these fluids was, for the most part, qualitatively similar to the behavior of the purified forms of plutonium-238 used in the studies described earlier by Barth and Mullen (1974). Generally, there was a rise in plutonium-238, -239, and americium-24] solubility when the pH was increased to 4.5 in order to simulate the duodenum. This initial increase in solubility was followed by an additional increase in plutonium solubility during the jejunal incubation period following the addition of bile and enzymes and adjustment of the pH to 6. In the case of americium-241, this additional increase was not consistent. The quantitative behavior of field-ingested plutonium differed considerably from that of purified plutonium238 dioxide reported by Barth and Mullen (1974).