Aerial Deposition of Plutonium in Mixed Forest Stands from Nuclear Fuel Reprocessing1
- D. C. Adriano and
- J. E. Pinder2
Concentrations of 238Pu and 239,240Pu were determined in bark, organic matter, and soil samples collected in the summer of 1975 from pine (Pinus taeda) and hardwood (Quercus falcata; Carya tormentosa) stands near a nuclear fuel reprocessing plant at the U. S. Energy Res. and Dev. Admin.'s Savannah River Plant near Aiken, S. C. The results indicated that tree crowns intercepted fallout Pu (Pu-bearing particles) and produced higher Pu concentrations in the organic matter and soil under tree crowns. Higher 239,240Pu concentrations were found under pines than under hardwoods. Plutonium concentrations in the O1 (litter, Aoo) and O2 (organic matter, Ao) layers were higher than those in mineral soil, but most of the Pu was contained in the mineral soil. Higher contents of 239,240Pu were observed near the tree stems than in locations outside of the tree crowns. In pines these values were 163 and 80 nCi 239,240Pu/m2, and in hardwoods, 122 and 80 nCi 239,240Pu/m2, for the respective locations, from the litter to the 15-cm depth.
The proportion of 238Pu contained in foliage, litter, and organic matter was greater than for 239,240Pu. However, the latter radionuclides had a greater proportion contained in the mineral soil. This observation is consistent with the more recent releases containing a higher percentage of 238Pu from reprocessing operation. Plutonium concentrations in the 5–15 cm depth indicated limited Pu mobility in soil, but 239,240Pu concentrations at this depth were higher near tree stems, suggesting greater mobility perhaps as a result of stem flow.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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