ESTIMATION OF AEROSOL PLUTONIUM TRANSPORT BY THE DUST-FLUX METHOD: A PERSPECTIVE ON APPLICATION OF DETAILED DATA. Joseph H. Shinn Environmental Sciences Division--Lawrence Livermore Laboratory ABSTRACT Two methods of dust-flux measurements are discussed which have been utilized to estimate aerosol plutonium deposition and resuspension. In previous studies, the methods were found to be sufficiently detailed to permit parameterization of dust-flux to the erodibility of the soil, and a seventh-power dependency of dust-flux (or plutonium flux) to wind speed was observed in worst case conditions. The eddy-correlation method is technically more difficult, requires high-speed data acquisition, and requires an instrument response time better than one second, but the eddy-correlation method has been shown feasible with new fast-response sensors, and it is more useful in limited areas because it can be used as a probe. The flux-gradient method is limited by critical assumptions and is more bulky, but the method is more commonly used and accepted. The best approach is to use both methods simultaneously. It is suggested that several questions should be investigated by the methods, such as saltation stimulation of dust-flux, simultaneous suspension and deposition, foliar deposition and trapping, erodibility of crusted surfaces, and horizontally heterogeneous erodibility. INTRODUCTION One of the key issues facing us in assessment of the health hazards due to plutonium aerosols is the manner in which practicle deposition and resuspension is rate limited by the underlying surface. We have made progress in the past by measuring the ambient Pu concentrations and by utilizing resuspension factors, but these methods lack detail in both the time and space resolutions possible with the present state of the art. For example, we are not yet able to determine vertical and horizontal Pu aerosol concentration over a Pu-contami-~ nated site with sufficient detail to determine the resuspension rate at low wind speeds. 171