harvest where the effect of DTPA was diminished. both ratio and uptake. This was the case for The level of chelator used was greatly in excess of that of 24am, which could account for the differences in ratio with increasing 24lam concentration in soil. The same situation would occur in crop fields if DTPA were applied--its level would be in excess of that of any radionuclide. The diminished effect of the chelator with time implied metabolism of the agent in the soil,which probably occurs, but slowly (Hale et al., 1962). The C.R. values without DTPA decreased slightly with increasing concentration (about threefold) and slightly (about fivefold) with harvest number (Table 2). Whether or not differences of this magnitude would have consequences of importance in food chain relationships is not clear at the moment. The range in 24am applied in soil was one order of magnitude. The uptake difference was less than one magnitude. The need exists for studies covering greater orders of magnitude and for greater time periods. The C.R. did not vary much for concentration in the presence of DTPA, but this may reflect the fact that the DIPA was at the same level for all concentrations of “414m. The higher C.R. for harvest 2 than harvest reflected the addition of the DTPA several days after seeding. Plants for harvest 1 were partially grown before DTPA was applied. The large decrease in C.R. for harvest 4 compared with harvest 3 reflects either metabolism of the chelator or reactions resulting in a lower degree of chelation of the 241am. The "Y'" exponent values which compare uptake at different concentrations gave different populations for with and without DTPA (Table 3). AnF value which statistically compares the two groups was 21.6 and highly Significant. The mean "Y" value for without DTPA was 0.53 + 0.07 SEM and 1.05 + 0.08 SEM with DTPA. A value of 1.0 represents uptake directuiy proportional to applied concentration and may indicate nonmetabolic or passive uptake. The value of 0.53 is too low to be 1n2 or 0.693 which is the decay constant which enters into many reaction rates. ACKNOWLEDGMENTS This work was supported by Contract 60-76-103, Fin No. B2017-6 between the Nuclear Regulatory Commission and the University of California. 632