Heavy element radionuclides (Pu, Np, U) and {sup 137}Cs in soils collected from the Idaho National Engineering and Environmental Laboratory and other sites in Idaho, Montana, and Wyoming

Fukushima Daiichi reactor source term attribution using cesium isotope ratios from contaminated environmental samples

“…A more likely reason for such a low calculated non-nuclear weapons fallout ratio is that the direct fallout 137 Cs concentration correction is not an appropriate approach for this specific matrix, such as would be the case if the JSAC samples were collected from a disturbed or low nuclear weapons fallout deposition location. One independent technique for evaluating whether such is the case is comparison of Cs/Pu ratios; as Cs and Pu from global nuclear weapons fallout have been shown to be strongly correlated in Japan [37] and other locations, [39,41] decreases in global fallout 137 Cs concentrations due to soil disturbances typically result in comparable decreases in 239 +240 Pu concentrations. [37,39,42] The JSAC soil has been certified to contain 0.025 ± 0.001 Bq of 239+240 Pu per kg soil with an isotope ratio consistent with global nuclear weapons fallout (0.180 ± 0.009).…”

137Cs Activities and 135Cs/137Cs Isotopic Ratios from Soils at Idaho National Laboratory: A Case Study for Contaminant Source Attribution in the Vicinity of Nuclear Facilities

“…Nuclear technologies have been used for the past 80 years to produce energy, medical isotopes, and atomic weapons. These activities have altered the global flux of anthropogenic fission products as a result of emissions during industrial operations, − their associated waste management practices, − accidents such as Chernobyl and Fukushima, and nuclear weapons tests. , Although the elements released from these industrial activities are not necessarily unique, the isotopic signatures of fission products are almost always distinct from natural sources and from each other, creating an opportunity to attribute them to specific sources or processes.…”

“…Surface soil samples were collected around the SDA in the early 1970′s by Markham et al; these samples revealed that considerable actinide contamination existed around this site . The majority of the actinide contamination has been attributed to waste from the Rocky Flats site which was disposed of in an acid pit called Pit 9; ,,, material from this excavation is believed to have been spread to the surrounding environment by pluvial flooding of this excavation followed by floodwater evaporation and subsequent particulate resuspension and redistribution via wind transport processes under arid conditions. , More recently, low level 137 Cs contamination has been identified in two of these soil samples taken within a drainage ditch on the immediate northeastern SDA perimeter; however, the source and extent of the 137 Cs contamination has yet to be identified.…”

“…The first possibility is airborne deposition of 137 Cs from the ICPP . Stack releases from the ICPP prior to 1970 have been documented but not quantified; large releases of 137 Cs from ICPP would likely have resulted from the waste evaporation and calcining operations that were conducted during the 1950′s and 1960′s. Airborne deposition of 137 Cs particulates from ICPP would be expected to decrease as a function of distance from the ICPP and follow the prevailing wind patterns of the area (e.g., the northeast-southwest direction, consistent with previous observations of actinide contamination patterns in the southeastern Idaho area , ).…”

Hydraulic and Geochemical Framework of the Idaho National Engineering and Environmental Laboratory Vadose Zone

“…Concentrations of contaminants that slightly exceed the essentially zero background concentrations (Knobel et al, 1992) have been detected in surficial sediments near the SDA (Markham, 1978; Beasley et al, 1998a, 1998b). For example, the range of 239+240 Pu concentrations near the SDA, expressed as total subsurface radioactivity per land surface area, is from about 50 pCi m −2 to greater than 600 pCi m −2 ; however, concentrations in 11 of 19 samples ranged from 270 to 650 pCi m −2 (Beasley et al, 1998a, Fig. 15).…”