title: Contributions of Rocky Flats releases to the total plutonium in regional soils.
abstract: Total 239,240Pu and the 240Pu:239Pu atom ratio were measured in soil samples from around the Rocky Flats Environmental Technology Site (RFETS) during 1992-1994. Mass isotopic data provided a sensitive technique to resolve low levels of RFETS 239,240Pu superimposed on plutonium from global fallout. Concentrations of 239,240Pu within this sample set ranged from 1.1 Bq kg(-1) offsite to 57 Bq kg(-1) onsite, and the 240Pu:239Pu atom ratio increased from 0.055 onsite to 0.123 at approximately 19 km east of the RFETS boundary. The relationship between 24OPu:239Pu atom ratios and distance indicated that a measurable RFETS contribution may have extended to > or = 19 km offsite in the easterly direction. Although the RFETS contribution to total plutonium at the offsite locations ranged from 24-90%, the overall inventory was relatively small. Total inventory estimates, for one transect, based on 239,240Pu and from 240Pu:239Pu atom ratio measurements were not significantly different.
authors.affiliation: Department of Radiological Health Sciences, Colorado State University, Fort Collins 80523, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Ibrahim
authors.forename: S B
authors.initials: SB
authors.lastname: Webb
authors.forename: F W
authors.initials: FW
authors.lastname: Whicker
mesh_terms: D003120:Colorado; D006077:Government Agencies; D006801:Humans; D013058:Mass Spectrometry; D011005:Plutonium / Q000032:analysis*; D011847:Radioactive Fallout / Q000032:analysis; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
chemical_list: D011847:Radioactive Fallout; D012990:Soil Pollutants, Radioactive; D011005:Plutonium