Radionuclide export by deer mice at a solid radioactive waste disposal area in southeastern Idaho.
Concentrations of 90Sr, 137Cs, 238Pu, 239+240Pu, and 241Am in deer mice tissues collected from a radioactive waste disposal area in southeastern Idaho were significantly (p less than 0.05) higher than those from a control area. The highest concentrations of Pu and Am occurred in pelts of deer mice inhabiting an area which had elevated surface and subsurface soil concentrations of these nuclides as compared to other Subsurface Disposal Area locations. Therefore, transuranic contamination in tissues likely originated from both soil depths. However, 137Cs and 90Sr in tissues likely originated from subsurface areas, since surface soils were below background concentrations for these nuclides. Based on a minimum of 6160 deer mice inhabiting the 36-ha waste disposal area over a 1-yr period, a total minimum inventory of 22.8 mu Ci radioactivity was contained in deer mice tissues. Of this estimate, 22.7 mu Ci activity was due to the radionuclides 90Sr and 137Cs. An estimated total of 8.4 mu Ci was transported from the disposal area in mice dispersing from the area. A calculated annual radionuclide inventory of 28.8 mu Ci in deer mice feces was deposited in and around the radioactive waste disposal area. Deer mice inhabiting the SDA are a mode of radionuclide uptake and transport; however, the environmental consequences of this transport mechanism are likely minimal. The results for deer mice, which make up 69% of the small mammal biomass, are discussed in relation to other small mammals within the disposal area. Other modes of transport associated with the deer mice, such as radionuclides in excavated soils associated with burrowing activities and predation, are also discussed.
The Uptake and Distribution of Buried Radionuclides by Pocket Gophers (Thomomys bottae)
Abstract Material Disposal Area G (Area G) at the Los Alamos National Laboratory is a low-level radioactive waste disposal facility. The noticeably high activity of pocket gophers on closed waste burial sites of various types at Area G resulted in the need to understand possible interactions between gophers and radioactive waste. Fossorial animals can influence the fate of contaminants by directly burrowing into waste trenches, pushing contaminated soil to the surface, or through indirect mechanisms such as consumption of contaminant-laden vegetation or the ingestion of soil. In our study, pocket gophers, mound soil, surface soil, and vegetation were collected at Area G and at offsite reference locations. The samples were analyzed for 241Am, 238Pu, 239Pu, 3H, and total U. It did not appear that gophers were responsible for any upward transport of radionuclides. Concentrations of 241Am, 238Pu, 239Pu, and 3H in some gophers, soil, and vegetation were higher than at reference sites; however, only 3H in gopher carcasses at only one of five sites within Area G was higher than a conservative ecological screening level.
Ocean predictive skill assessments in the South Atlantic: Crowd-sourcing of student-based discovery
Autonomous Underwater Gliders have over a decade long history of successful regional deployments serving scientific, societal and security needs in application areas ranging from pole to pole and including the full range of water depths from shallow coastal seas to the deep ocean. Glider deployments covering the basin scale are much fewer, but are a growing capacity as demonstrated by the Woods Hole to Bermuda line that crosses the Gulf Stream, the Atlantic Crossing line that follows the Gulf Stream, and the basin circling flights now being conducted as part of the Challenger Glider Mission. The next step in the evolution of the global Challenger mission is to enable an ensemble of modelers from different institutions and agencies to participate in a meaningful way. This process with be formalized in 2014 by leveraging the data management tools of the U.S. Integrated Ocean Observing System (IOOS) and the education tools of the U.S. National Science Foundation's (NSF) Ocean Observing Initiative (OOI). The Education Visualization (EV) tools developed by the OOI's Education and Public Engagement (EPE) Implementing Organization (IO) are currently being configured through the cyber OOI net to display real time OOI glider data with intuitive interactive browser-based tools, reducing the barriers for student participation in sea exploration and discovery. Through U.S. IOOS, forecast ocean data will be harvested from the ephemeral ocean snapshots produced by an ensemble of ocean models along the same glider tracks as Challenger. The parallel observed and forecast datasets, both evolving in real time, will be accessible through the same OOI EV tools, enabling student participation in a crowd-sourced ocean predictive skill experiment. The result will satisfy one of the important goals of the Challenger mission by enabling students to assess of the quality of the ensemble of available global scale ocean models. Student research team projects that use the new model data comparison capabilities will be conducted during the summer of 2014. Students will compare an ensemble of the global ocean models along the high velocity transport pathways by gliders on basin-scale missions, such as one that traverses the northern side of the South Atlantic gyre along the Brazilian shelfbreak. The lasting impact of the Challenger mission will be a global fleet available to respond to events, an assessment of the ocean models along the fastest ocean transport pathways, and the establishment of a network of gliderports for global response.