title: Mechanical environmental transport of actinides and ¹³⁷Cs from an arid radioactive waste disposal site.
abstract: Aeolian and pluvial processes represent important mechanisms for the movement of actinides and fission products at the Earth's surface. Soil samples taken in the early 1970's near a Department of Energy radioactive waste disposal site (the Subsurface Disposal Area, SDA, located in southeastern Idaho) provide a case study for studying the mechanisms and characteristics of environmental actinide and (137)Cs transport in an arid environment. Multi-component mixing models suggest actinide contamination within 2.5 km of the SDA can be described by mixing between 2 distinct SDA end members and regional nuclear weapons fallout. The absence of chemical fractionation between (241)Am and (239+240)Pu with depth for samples beyond the northeastern corner and lack of (241)Am in-growth over time (due to (241)Pu decay) suggest mechanical transport and mixing of discrete contaminated particles under arid conditions. Occasional samples northeast of the SDA (the direction of the prevailing winds) contain anomalously high concentrations of Pu with (240)Pu/(239)Pu isotopic ratios statistically identical to those in the northeastern corner. Taken together, these data suggest flooding resulted in mechanical transport of contaminated particles into the area between the SDA and a flood containment dike in the northeastern corner, following which subsequent contamination spreading in the northeastern direction resulted from wind transport of discrete particles.
authors.affiliation: Department of Chemistry, Washington State University, PO Box 644630, Pullman, WA 99164-4630, USA; Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2805, USA. Electronic address: mathew.snow@inl.gov.
authors.forename: Mathew S
authors.initials: MS
authors.lastname: Snow
authors.affiliation: Department of Chemistry, Washington State University, PO Box 644630, Pullman, WA 99164-4630, USA.
authors.forename: Sue B
authors.initials: SB
authors.lastname: Clark
authors.affiliation: Department of Chemistry, Washington State University, PO Box 644630, Pullman, WA 99164-4630, USA.
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Morrison
authors.affiliation: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2805, USA.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Watrous
authors.affiliation: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2805, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Olson
authors.affiliation: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2805, USA.
authors.forename: Darin C
authors.initials: DC
authors.lastname: Snyder
mesh_terms: D008671:Actinoid Series Elements / Q000032:analysis*; D002588:Cesium Radioisotopes / Q000032:analysis*; D003889:Desert Climate; D007061:Idaho; D011834:Radiation Monitoring; D011850:Radioactive Waste / Q000032:analysis*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D064091:Waste Disposal Facilities
chemical_list: D008671:Actinoid Series Elements; D002588:Cesium Radioisotopes; D011850:Radioactive Waste; D012990:Soil Pollutants, Radioactive
keywords: Am-241; Americium; Cs-137; Flood; Particulate; Plutonium; Pu; Wind