These measurements are the corner- are derived from the data. stone of the resuspension program. . . Measurements have also been . made of particle-size distributions of airborne mass and 239 Pu. A time-dependent resuspension factor* model was developed as an interim, conservative model for prediction of the resuspendedplutonium concentrations. this model is time, The only independent parameter in so it was considered appropriate that the model be consistent with higher reported measurements of the resuspension factor. This model differs from other such models in that time-dependency is more complex and consistent with actual measurements over aged plutonium sources. This model was used to develop a protective guideline for soil contamination immediately after deposition; the result is 1 uCi/m? for a 50-yr dose commitment of 75 rem. A mass-loading resuspension model was developed which is appropriate for reoccupation of contaminated land several years after deposition, and at which time the contaminant may be assumed to be intimately associated with the host soil. Using the model, predicted results were found to be in good agreement with experimental data. A protective guideline was also developed for this situation; the result is 7 nCi/g in the top 1 cm of soil for a 50-yr dose commitment of 75 rem. The eddy correlation method was used for the first time to derive a quantitation of dust flux. This study also resulted in a more generally useful method of predicting resuspended soil concentrations and fluxes when it was ascertained that both are expressible as a power function of friction velocity. The power, however, varies from location to location and was tentatively parameterized as a function of the Chepil Soil Erodibility Index (Chepil and Woodruff, 1959). The above results were tested for applicability to 239Pu resuspension at the GMX location. Generally good agreement was found between predicted and measured concentrations at sampling loca- tions close to the area of maximum ground deposition. At farther locations, the complicating effect of a nonhomogeneous source 94