For situations where it appears kriging can be applied, the investigator should consider carefully whether the benefits to be gained from kriging are worth the extra time and expense of performing the necessary structural analysis and kriging of the data. The average Pu concentrations and confidence limits over 100- x 100-foot cells are clearly more infor- mative and useful than the stratum averages reported by Gilbert et al. (1975). They would be particularly useful in a cleanup situation where the cell averages might be used to indicate those portions of the study site requiring remedial action. Furthermore, if the mathematical assumptions underlying kriging are not unreasonable at a given site, then theory tells us that the estimates obtained using kriging are "best" in that they are unbiased and have minimum variance of all linear estimators we might try (see Barnes et al., 1977, for other advantages to kriging). An initial cost of kriging involves training a statistician in the theory of kriging (so that inappropriate applications are avoided) and writing or acquiring the necessary computer programs. The availability of the kriging program BLUEPACK on the Nevada Operations Office computer is a tremendous help in that regard. However, as with any computer program, BLUEPACK can be used inappropriately. Hence, a person experi-~ enced in the use of BLUEPACK and familiar with field and laboratory procedures is essential if a serious attempt at kriging is anticipated. It is also clear that the use of kriging cannot overcome a lack of data. It is important to design a field sampling program so that enough information over the entire study site is available for estimating spatial pattern. Hence, the design of the sampling plan is an important step in any environmental sampling effort. ACKNOWLEDGMENTS We would like to thank Madaline Barnes of the Desert Research Institute, Las Vegas, and Pam Doctor and Lee Eberhardt of Battelle-Northwest Labora- tories for the stimulating discussions we have had about kriging and its potential for application to transuranic field studies. Special thanks are also extended to Mary Lou Lemon of Battelle-Northwest for her excellent work in typing the manuscript, The figures were very ably drawn by the Graphics Section, Communications Department of Battelle-Northwest. The support of Mary G. White of the NAEG in our efforts at evaluating the potential of kriging for transuranic studies is also gratefully acknowledged. 402