Instrumentation Limitations. There are several significant limitations of the various portable survey instruments which must be considered before measurements made with them can be meaningfully interpreted and utilized. These limitations will be discussed here to prevent misinterpretation of such measurements and to show why certain instruments were not utilized more fully. The soil moisture problem affecting the alpha instruments has been indicated. The problem was indeed a serious one. Until the survey made during the "dry" season in January, the surface alpha contamination on YVONNE could only be surmised from soil sample data. These data are sparce, even after the soils collection effort, and are certainly not enough to define the limits of surface alpha contamination on YVONNE to any satisfactory precision. The cost of collecting and analyzing sufficient soil samples to give better precision would be tremendously prohibitive. Negative measurements made with alpha-only detecting instruments, with the usual existing soil moisture conditions, cannot be interpreted as confirming the absence of alpha contamination on those surfaces monitored. Such negative measurements can only be interpreted to mean that alpha contamination was not detected. Large quantities of surface alpha contam- ination could still be present, masked by the soil moisture. Indeed, they are, as evidenced by the dry season survey. The single effort to survey the surface of YVONNE for alpha emitters with the sensitive LLL Blue Alpha Meter was quickly frustrated before monitors could get beyond the PIS/ QUINCE area due to the return of the rain in February. What contamination that was detected was somewhat spotty, generally confined to the outer areas of the FIG/QUINCE SGZ area with levels ant cver A of Up,to, 100, 000 dpm/100 en*.