10° ry | FOOD-CHAIN KINETICS OF RADIONUCLIDES yl | a a ~ = | I T O—-—O OBSERVED MEANS (n=18 TO 20) ~ d-—A HYPOTHETICAL MEANS BASED ON _J Lo P4=7200 PC/G (DRY) 1,=5.0 DAYS 7 Wp:100 G/DAY T,=2.0 DAYS _] F,=0.18 (EQUATION 6) — —_— 4 — — #— T = oO a s T 771 10 L -—T 74 ~ a z — aad bre — —_ L 4 < O = 10! 0 tot 3 10 | 15 | ‘ 20 25 30 35 DAYS AFTER DETONATION Fig. 6—Observed and hypothetical average concentrations of 11I in the thyroids of rabbits collected from representative locations (see Fig. 2) in the Sedan fallout field at various times after the detonation. DISCUSSION These results seem to indice that Eqs. 4 to 6 function satisfactorily, with estimated parameter values based on observed means, in explaining the early food-chain kinetics of ®°Sr and ‘I on plants and in the skeletons or thyroids of rabbits collected from 20 representative locations in the Sedan fallout field at between 5 and 60 days after the detonation. The input parameters for Eqs. 4 to 6 (W,, W,, £, f., Tp, T, and T,) are known to vary; but the means of these values can be used, with fair success, as though they were constants. This deterministic approach to the problem permits us to describe and explain certain aspects of food-chain kinetics in relatively simple mathematicalterms. It may also permit us to make errors in estimating parameter values; these errors are difficult to detect because the several parameters are AIO

Select target paragraph3