UPTAKE AND TRANSLOCATION OF NEPTUNIUM‐237, PLUTONIUM‐238, PLUTONIUM‐239,240, AMERICIUM‐241, AND CURIUM‐244 BY A WHEAT CROPSCHULZ, R. K.; RUGGIERI, M. R.
doi: N/Apmid: N/A
We carried out a plant uptake and translocation experiment in which a wheat crop was grown on Yolo soil contaminated with 237Np, 238Pu, 239,240Pu, 241Am, and 244Cm. Studying pot-to-pot variability, we found the data a coefficient of variation of 21 percent. About 9 percent of this variability we ascribe to that of radioanalyses of the plant material. Both uptake and translocation of 238Pu and 239,240Pu were found to be identical. Likewise, both uptake and translocation of 241Am and 244Cm were identical. The Pu concentration was about 103lower in the grain than in the bottom one-half of the stem plus leaves.
EFFECT OF CONCENTRATION ON 241Am UPTAKE BY PLANTS WITH AND WITHOUT DTPA TREATMENTWALLACE, A. ; ROMNEY, E. M.; MUELLER, R. T.; SOUFI, S. M.
doi: N/Apmid: N/A
The DTPA chelating agent (diethylenetriamine pentaacetate) enhanced shoot uptake of 241Am from solution culture by bush bean plants by promoting transfer of 241Am from roots to shoots, rather than by increasing total uptake. The major part of the radionuclide was associated with roots in treatments without DTPA. Some alpha radiation damage was suspected when large quantities of 241Am were transferred to shoots. The leaf concentration ratio (CR) decreased 3.9 times, with a 16-fold increase in concentration of 241Am applied in soil without DTPA. In contrast, the CR was positively related to levels of 241Am in soil with added DTPA. The 241Am uptake ratio for treated/untreated soils increased with higher concentrations of applied 241Am. Uptake coefficients for leaves (Y values in the expression (C1/C2)Y= uptake ratio) for comparing two different concentrations of 241Am (C1and C2) were about 0.5 without DTPA treatments and over 1 with DTPA treatments. Increasing pot size with a constant activity/gram in soil of 241Am decreased the CR in bean plants only slightly at the largest pot size, compared with smaller pots.
PLANT UPTAKE AND TRANSPORT OF 241AmWALLACE, A. ; ROMNEY, E. M.; MUELLER, R. T.; SOUFI, S. M.
doi: N/Apmid: N/A
We conducted several experiments with 241Am to obtain a more complete understanding of how this transuranium element is absorbed and transported in plants. In a plant species (Tamarix pentandra(Pall.) that has salt glands in the leaves excreting NaCl and other ions, 241Am was not pumped through these glands. Cyanide, which forms complexes with any metals, when applied to a calcareous soil, greatly increased the transport of 241Am into stems and leaves of bush bean plants. When a noncalcareous soil was used, the effect of cyanide was less pronounced. A less stable complex is formed at the lower pH. Radioactive cyanide (14C) was also transported to leaves and stems. When radish was grown in both calcareous and noncalcareous soils, 241Am appeared to be fixed on the peel so firmly that it was resistant to removal by HNO3washing. The chelating agent DTPA induced increased transport of 241Am to leaves and into the fleshy roots of the radish. This effect was little dependent upon pH. Data for ‘Golden Cross' hybrid corn grown in solution culture showed at least seven times as much 241Am transport to the xylem exudate when DTPA was the external solution around roots compared with no DTPA, indicating, along with data from other plant species, that 241Am is transported in the xylem exudate.
RELATIONSHIP BETWEEN THE CHEMICAL EXTRACTABILITY OF SEVERAL TRANSURANIC ELEMENTS FROM SOILS AND THEIR UPTAKE BY WHEAT PLANTSNISHITA, H. ; WALLACE, A. ; ROMNEY, E. M.; KINNEAR, J.
doi: N/Apmid: N/A
We studied the relationship between chemical extractability and wheat plant uptake of 237Np, 239,240Pu, 241Am, and 244Cm from seven widely different kinds of soils. The chemical extractants used were distilled H2O, 0.05 MCaCl2, and 1 MNH4OAc. The relative order of magnitude of 237Np extractability by the extractants was H2O < CaCl2< NH4OAc. The relative order of magnitude of 239,240Pu, 241Am, and 244Cm extractabilities were generally H2O, CaCl2< NH4OAc. The amount of the extractable fraction of each tracer nuclide was conditioned by soil type. The 241Am and 244Cm uptake by wheat plants correlated with the extractability of these nuclides by H2O, CaCl2, and NH4OAc at the 5 percent level of significance or better. The 237Np uptake by the plants correlated with its extractability by CaCl2and NH4OAc, but not by using H2O. With 239,240Pu, poor correlation was obtained with all of the extractants used when no soil was excluded from statistical analyses. When one (Lyman silt loam) of the seven soils was excluded, the correlation was significant at the 5 percent level for NH4OAc. The most suitable extractant for 237Np, 241Am, and 244Cm was CaCl2.
THE INTERACTIONS OF LOW‐LEVEL, LIQUID RADIOACTIVE WASTES WITH SOILSPOLZER, W. L.; FOWLER, E. B.; ESSINGTON, E. H.
doi: N/Apmid: N/A
We interacted a low-level radioactive waste with the respective horizons of two soils series, the Fuquay and the Fayette. The sorption of the soluble radionuclides was determined by batch reaction methods. Cesium-137 was sorbed to a very high degree, greater than 95 percent, and that degree of sorption was independent of both the soil horizon and the soil series. Uranium also was sorbed to a high degree by all horizons, with sorption by the Fuquay A2 and Fayette Ap soils at 60 to 70 percent and at 90 percent or more by the other horizons. The lower degrees of sorption were attributed to the presence of a negatively charged uranium species, probably a uranium carbonate complex. Soluble plutonium and americium were sorbed to a high degree, greater than 75 percent, by all horizons except for Fuquay AP and A2. Those two horizons solubilized, at least in part, the plutonium and americium associated with the insoluble fraction of the waste. The complexing of those radionuclides into a nonsorbable form was attributed to an organic complex.
UPTAKE OF PLUTONIUM FROM SOILS CONTAMINATED BY A NUCLEAR FUEL CHEMICAL SEPARATIONS FACILITYMCLEOD, K. W.; ADRIANO, D. C.; CIRAVOLO, T. G.
doi: N/Apmid: N/A
A greenhouse experiment investigated factors influencing root uptake of Pu by agricultural crops from soils receiving effluents from a nuclear fuel chemical separations facility. Results indicate that uptake of 238Pu and 239,240Pu from soil was very low (concentration ratio of 10−3or lower). Large differences in Pu soil concentrations did not produce uptake differences, indicating that uptake was independent of soil concentrations in this case. Both liming the soil and chelate addition to limed soils produced only very slight differences in uptake of Pu. Plutonium concentrations in clover and soybean were similar or slightly higher than those for corn, wheat, and bahiagrass. Reproductive parts of these crops had similar concentrations of Pu to their corresponding vegetative parts. Only very minimal quantities (<10 fCi/g dry weight) of Pu were incorporated into edible portions of crops grown in soil containing 5 pCi Pu/g and would pose little health hazard to man if ingested.
SEQUENTIAL DETERMINATION OF NEPTUNIUM‐237, PLUTONIUM‐238, PLUTONIUM‐239,240, AMERICIUM‐241, AND CURIUM‐244 IN PLANT MATERIALSCHULZ, R. K.; WINK, G. T.; FUJII, L. M.
doi: N/Apmid: N/A
We describe a procedure for the sequential determination of 237Np, 238Pu, 239,240Pu, 241Am, and 244Cm in plant material. The plant sample is decomposed completely by a combination of dry ashing and wet digestion; the radionuclides are then coprecipitated with ferric hydroxide. Americium-curium, plutonium, and neptunium fractions are sequentially extracted with tri-isooctylamine (TIOA). Excess salts are then removed from the americium-curium fraction by ferric hydroxide precipitations in a two-step procedure, first using ammonium hydroxide and then sodium hydroxide, followed by iron removal by cation exchange. Trace amounts of iron are removed from the plutonium and neptunium fractions by ion exchange. Each fraction is electrodeposited and analyzed by alpha spectrometry. Recovery for the neptunium fraction is about 80 percent, and for plutonium, americium, and curium, better than 90 percent. Yields are corrected by recovery of added tracers.
EFFECT OF DTPA ON CONCENTRATION RATIOS OF 237Np AND 244Cm IN VEGETATIVE PARTS OF BUSH BEAN AND BARLEYROMNEY, E. M.; WALLACE, A. ; MUELLER, R. T.; CHA, J. W.; WOOD, R. A.
doi: N/Apmid: N/A
We grew bush beans, barley, and rice in two different soils (noncalcareous Yolo and calcareous Hacienda) in a glasshouse with 530 pCi/g 237Np or 15 040 pCi/g 244Cm mixed into separate containers of the soil. The chelating agent DTPA at 100 μg/g soil was added to half of the containers. The concentration ratio (CR) for 237Np without DTPA was two orders of magnitude higher than for 244Cm without DTPA for all three plant species. The DTPA increased the CR of 244Cm by two (for Yolo) and three (for Hacienda) orders of magnitude, but had no influence on that for 237Np. Actually, the DTPA nearly equalized the uptake of 237Np and 244Cm for Yolo soil and resulted in greater uptake of 244Cm with the Hacienda soil. In bush beans, both 237Np and 244Cm CRs were higher in primary leaves than in trifoliate leaves, which were higher than for stems. The CRs for bush beans were generally higher for both 237Np and 244Cm than for either barley or rice, especially without DTPA.