Oo Hy Im wooded areas the non-uniform distribution of tree canopies will lead to unsveness in deposition of fallout materials. Soils having vary high earthworm activity should be avoided because of uneven mixing of the soil to considerable depths. Rodent activity also renders areas unsuitable for sampling. Sampling Methods and Toois The degree of uniformity of fallout deposition has not had adequate Csfinition. However, it is known that a sample of 1 to 2 square fest will give a good answer if the area is made up of a composite of at least £0 individual plugs or cores. These individual cores should be taken on some kind of systematic scheme or grid. An area the size of & gsmali room is adequate for the grid. If one expects to resample a given area on a yearly basis, for example, a straight line of cores about one Foot apart tas been shown to be satisfactory. (13) The number of cores must be known so that the analytical data can be related to a definite ground suriate ara. = he OR to the oO oO rH Tool3 for taking the sample may be anything that will take a oO tf oe es SEEGER euitivetsé Jand. that is of enual area through its entire depth. On soil with reasonrabie base exchangs capacity due either to clay or organic sample to the depth of 8 inches is adequate at the present 8s, it may bé necessary to go to deeper samples in tue strontium-90. A good pair of sampling tools is