The original disposal site (fig. 1) as constructed in 1945 at Los Alamos consisted of four trenches of trapezoidal cross section 120 feet long, 20 feet wide and 6 feet deep. The four trenches were arranged in a square configuration with the first two connected to the process plant by a tee pipe. The primary trenches were connected by overflow pipes to the other two trenches. It was near the discharge end of one of the overflow pipes that coring was done for the samples reported on here. Each trench was filled with coarse rock debris, grading from large boulders in the bottom to sand at the surface. Unprocessed waste solutions were discharged to these trenches from 1945 to 1952. Estimates of the chemical composition and plutonium content are based primarily on data collected towards the end of that period. Beginning in 1952, through about 1967, the trenches received varying annual volumes of effluent from a liquid waste treatment plant; no unprocessed wastes were discharged after 1952. The estimated chemical composition and plutonium content of the waste discharged to the trenches is indicated in Table 1. Some additional £111 was added to the area during the late 1960s and 1976s, raising the ground surface to a meter or so above the top of the trenches. Precipitation falling on the area is predominantly reevaporated to the air, or FIGURE MATERIALS AND METHODS LIQUID WASTE DISPOSAL SITE However, several sites exist which have received low level waste. One such has been selected for this study; a liquid waste disposal trench at Los Alamos Scientific Laboratory that was used for waste disposal starting in 1945. This site does not match the description of an ideal disposal method since liquid was pumped directly into a trench excavated fin porous rock and allowed to percolate downward, However, it can be considered as a rapid acceleration of what could occur in a deep repository in which water intruded. see fillad with coarse rock An understanding of the migrational behavior of actinides in geological material is therefore extremely important. Since there are no operating disposal sites as deacribed, the information obtained up to now has been the result of supposition, theoretical models and in our own case small scale laboratory models. Important as these results are, they do not eliminate the need of a large scale pilot plant on-site experiment. text burial with adequate buffer zones appear to be one of the most promising approaches. Details of such a method have not been worked out but it seems reasonable to assume high level process waste solutions will be calcined and converted to ceramics or glasses before loading into retrievable containers. These containers would then be inserted into selected geologic formations at appropriate depths (1000 meters) in isolated geographic locations. In spite of these precautions, one must consider the rock or other geological sttatum in which the waste filled containers have been buried as the ultimate barrier. Corrosion and leakage may violate the integrity of any container over the 105 year time span required for safekeeping.