Variability in background levels of surface soil radionuclides in the vicinity of the US DOE waste isolation pilot plant

• Published in: Journal of environmental radioactivity Vol. 60; no. 3; pp. 275 - 291
• Main Authors: Kirchner, T.B., Webb, J.L., Webb, S.B., Arimoto, R., Schoep, D.A., Stewart, B.D.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2002; Elsevier
• Subjects: Aluminum - analysis; Applied sciences; Background; Background radiation; Clay (material); Concentration gradient; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring; Exact sciences and technology; Fallout; Fission products; Isotopes; Lead Radioisotopes - analysis; New Mexico; Pilot plants; Pollution; Pollution sources. Measurement results; Pollution, environment geology; Radioactive Waste; Radioactivity; Radioisotopes - analysis; Reference Values; Refuse Disposal; Sampling; Sand (material); Silts; Soil (material); Soil and sediments pollution; Soil Pollutants, Radioactive - analysis; Soil pollution; Soils; USA; Variability; Wastes; United States; New Mexico; North America; America; USA, New Mexico; Soils; USA; Background; Fallout; Variability; Radioactivity; Cluster analysis; Radioactive pollution; Spatial variability; Statistical analysis; Property of soil; Radioisotope; Soil pollution; Texture; Radioactivity measurement; Correlation analysis; Environment impact; Radioactive waste storage; Sampling; Background radiation
• ISSN: 0265-931X; 1879-1700
• DOI: 10.1016/S0265-931X(01)00088-1

Concentrations of radionuclides were measured in soils from a grid of locations surrounding the US Department of Energy Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico and from a grid on a reference site approximately 20 km southeast of the WIPP site. Each of the two grids has 16 sampling locations (grid nodes) systematically distributed within an area of 16,580 ha. Sampling was conducted prior to the arrival of the first waste shipment at WIPP. Thus, the 137Cs and 239,240Pu in the soil are expected to have been deposited as global fallout, although the Gnome Site, 8.8 km southwest of the WIPP, is also a potential source of 239,240Pu and fission products. The reference grid has significantly higher concentrations of fallout and natural radionuclides than the WIPP grid. Up to 80% of the total variability in radionuclide concentrations across the two grids is attributable to differences between grid nodes. Differences between replicates within a location account for 44–50% of the variability in concentrations of the uranium isotopes, but only 11–17% of the variability in the concentrations of the other radionuclides. Samples having similar abundance of radionuclides were spatially aggregated across the terrain. The activity concentrations of the radionuclides were strongly correlated with the concentrations of Al and Pb, and with the percentages of sand, silt and clay in the soil. Normalizing radionuclide concentrations to the concentration of Al or percent fine particles can help adjust for differences in soil textures among samples and facilitate the detection of gradients or temporal changes in soil concentrations.