REVIEW OF RESUSPENSION MODELS 231 



with the tracer particles, have given values that are extremely useful for appUcation. Slinn 

 (1978) has provided parameterization concepts that aid in understanding. 



This is not to say that additional work is not needed. Further studies of both the dust 

 flux and resuspension rate at contaminated areas in various regions and types of soil are 

 definitely needed along with models, such as those of Gillette (1974) and Shinn et al. 

 (1976), which provide relationships between the resuspension and readily measured 

 parameters that can be used to estimate resuspension rates. Concurrent studies of the dust 

 flux and resuspension of a contaminant are badly needed, particularly in undisturbed 

 areas apart from agricultural soils. The dust-flux model requires assumptions as to the 

 connection between resuspension of a contaminant and the dust flux. The only 

 checkpoint now available is the measurements at the GMX Area of the dust flux by Shinn 

 etal. (1976) and the plutonium resuspension rate by Anspaugh et al. (1975). In 

 particular, additional data are needed on resuspension by mechanical disturbance. Few 

 appropriate experiments are available, and it is frequently difficult to interpret them in a 

 manner that provides useful results. A particular area of concern for which very few data 

 are available is the possibility of contamination while playing and working in an area with 

 subsequent transfer to a place where inhalation is more probable. Extreme examples of 

 this would be pulling a contaminated garment over one's head or contaminating pillows 

 or other bed clotliing. Although one could feel that this could not be a major source of 

 exposure, we cannot tell until the experiments are done. 



A primary purpose of this chapter is to choose resuspension parameters to be used in 

 the calculation of the dose to individuals in a contaminated area. The study has 

 reinforced our previous prejudice that the resuspension factor is not the method for use 

 because of the failure of this method to account for many of the variables and because 

 the conditions of the measurement are seldom described in sufficient detail to allow 

 intelligent extrapolation to areas different from those in which the measurements were 

 made. There is some usefulness to this technique, however, in describing the exposure of 

 the individual causing the disturbance. 



The resuspension rate has been our favorite method because of the capability of 

 integrating over a contaminated area using accepted dispersion and deposition parameters 

 to provide concentration isopleths around the area. For a specific situation in which the 

 soil and meteorological parameters can be defined, this is still the preferred method, and 

 the state of the art is rapidly approaching sufficient detail that this can be done. 



However, for a generic study the mass-loading approach seems to be best. The work 

 of Tamura (1977), the U. S. Environmental Protection Agency (1977), and Johnson, 

 Tidball, and Severson (1970) all indicate that even this approach requires revision for the 

 distribution of contamination in the soil. However, as has been pointed out, there are 

 factors that tend to compensate for this, such as the size of the area, and the magnitude 

 of the correction factor proposed by the U. S. Environmental Protection Agency (1977) 

 and Tamura (1977) is only on the order of 1.5 to 2, a value that tends to get lost in the 

 noise of the other uncertainties. In addition, the success shown by Anspaugh (1974) in 

 predicting the concentrations of several nucHdes in widely different climates and soil 

 types is encouraging. 



Anspaugh (1974) used a mass loading of 100 jUg/m^ in his comparison. The measured 

 values were primarily ambient air and included no component for mechanical 

 disturbance. In view of the agreement found in his study, we would propose the use of 

 200 Afg/m^ for generic studies to make allowance for these other types of exposure. This 



