RETENTION OF A FALLOUT SIMULANT CONTAINING 134CS BY PINE AND OAK TREES

Small white pine (Pinus strobus) and red oak (Quercus rubra) trees were contaminated in the field with a fallout simulant consisting of 88–175 μ dia. quartz particles containing 134Cs. Whole plants were harvested at intervals up to 33 days after application of the simulant, and the 134Cs retention by each species was determined. The initial fraction of the simulant retained by foliage was higher in the oaks (0.35) than in the pines (0.24). However, after 1 hr, the broad leaved oaks had lost 90.5% of the initial 134Cs concentrations while the pines had lost only about 10%. These early retention differences are related to the effects of wind on the two distinct foliage types. Effective half lives were calculated for both species at intervals of 0–1 day, 1–7 days and 7–33 days. For pine trees these values were 0.25, 4.53 and 20.66 days, respectively. For oaks they were 0.12, 1.41 and 24.86 days. Loss of particles (134Cs) was due, primarily, to the weathering action of wind and rain during the study. The effects of wind and the first rain following contamination accounted for a large percentage of the total radionuclide loss during the study. © 1969 Health Physics Society.