In semiarid regions, where potential evapotranspiration greatly exceeds precipitation, it is theoretically possible to preclude water form reaching interred wastes by (i) providing a sufficient cap of soil to store precipitation that falls while plants are dormant and (ii) establishing sufficient plant cover to deplete soil moisture during the growing season, thereby emptying the water storage reservoir of the soil. Here we discuss the theory and rationale for such an approach and then present the results of a field study to test its efficacy at the Idaho National Engineering Laboratory (INEL). We examined the capacity of four species of perennial plants to deplete soil moisture on simulated waste trenches and determined the effective water storage capacity of the soil. Those data enabled us to estimate the minimum depth of fill soil required to prevent deep drainage. Any of the species studied can use all of the plant‐available soil water, even during a very wet growing season. The water storage capacity of the soil studied is 17% by volume, so a trench cap of 1.6 m of soil should be adequate to store precipitation received at the INEL while plants are dormant. We recommend a fill soil depth of 2 m to provide a margin of safety in case water accumulates in local areas as a result of heavy snow accumulation, subsidence, or runoff. Fill soil requirements and choice of plant species will vary, but the concepts and general approach are applicable to other shallow land burial sites in arid or semiarid regions.

From 1954 through 1970, transuranic waste from the Rocky Flats facility near Golden, Colorado, was shipped to the Idaho National Engineering Laboratory and buried in the Subsurface Disposal Area (SDA) at the Radioactive Waste Management Complex. Soil samples collected near the SDA indicate that this storage has resulted in transuranic contamination outside the SDA perimeter. Maximum concentrations in surface soils (0–4 cm) occurred in the drainage depression near the perimeter of the SDA and were 2,048 nCI 241Am/m2, 1,377 nCi 239Pu/m2, and 32 nCi 238Pu/m2. Contamination outside this drainage channel was lower and has primarily spread in the northeast‐southwest directions. The maximum distances from the SDA perimeter that above background concentrations of 241Am, 239Pu, and 238Pu could be detected were approximately 2,500, 2,400, and 1,000 m, respectively. Surface water runoff in 1962 and 1969 and wind transport appear to be the primary mechanisms which transported these nuclides out of the SDA. The vertical soil migration of 238Pu from 0–4 cm to the 4–8 cm depth was significantly greater than that for 239Pu (P = 0.001).Hides and gastrointestinal tracts of deer mice (Peromyscus maniculatus) had higher concentrations of transuranics than lungs or carcass. Ingestion appeared to be a more important mechanism than inhalation in the intake of transuranics into the deer mice. The 241AM/239Pu ratio in the carcass was significantly (P = 0.02) higher than the ratio in soil indicating a greater uptake of 241Am into deer mice.The data indicate that 238Pu, 239Pu, and 241Am may behave differently in the terrestrial environment.

During 1978 and 1979, small mammals excavated a total mass of 12,450 kg soil to the 36‐ha surface of a solid radioactive waste disposal area in southeastern Idaho. Elevated concentrations of 238Pu, 239,240Pu, and 241Am were detected in excavated and surface soils in the waste disposal area. The inventory of 66 µCi (90Sr, 137Cs, 238Pu, 239,240Pu, and 241Am) transported to the surface of the waste disposal area by small mammal excavations was significantly (P ≤0.05) greater than the 20 µCi estimated to occur in excavated soils at a control area where no radioactive waste was disposed. Seventy‐seven percent of the radioactivity in soil excavated to the surface of the waste disposal area by small mammals was 238Pu, 239,240Pu and 241Am; 98% of the radioactivity in excavated soil in the control area was 90Sr and 137Cs. Small mammal burrowing is a mode of transuranic radionuclide transport to the surface of the waste disposal area; however, the total amount of plutonium in excavated soils was only 0.05% of the amount estimated to occur in waste disposal area surface soils in 1974.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.Wiley is collaborating with JSTOR to digitize, preserve and extend access to Ecology Abstract. Radiation doses received by small mammals inhabiting a dry radioactive leaching pond on the Idaho National Engineering Laboratory Site in southeastern Idaho were determined by surgically implanting lithium fluoride thermoluminescent dosimeter (TLD) chips. One hundred eightytwo TLD packets were implanted in 3 species: white-footed deer mouse (Peromyscus maniculatus), least chipmunk (Eutamias minimus), and Ord's kangaroo rat (Dipodomys ordii), with 65% recovery.All species from the radioactive leaching pond received significantly greater (P < .001) doses than control species. The deer mice received a mean dose equivalent rate of 160 mrem/day which was significantly greater (P < .001) than the mean dose equivalent rates received by least chipmunks (17 mrem/day) and Ord's kangaroo rats (6 mrem/day). The mean dose received by deer mice was 8% of the maximum air exposure recorded near the ground surface of the leaching pond. The maximum dose rate received by an individual deer mouse was nearly 50% of the maximum exposure rates in the study plot.Interspecific dose differences appeared to be related to habitat preference. Deer mice were most frequently captured on the gravelly and sparsely vegetated dry pond bed which had site exposure rates of 200 to 2000 mRoentgen/day. Conversely, chipmunks and kangaroo rats were usually captured on the pond banks which were adjacent to areas with sandy soil and denser vegetation. Site exposure rates on the pond banks ranged from 10 to 30 mRoentgen/day. Doses received by individuals of each species had high variation which appeared to be caused by the variable air exposure rates and the mobility of the small mammals. Intraspecific differences in activity, behavior and home range may have also influenced the dose variability in individual rodents.The advantage of implanted TLD over externally attached TLD and possible radiation effects on small mammal populations are discussed.

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