The distribution of depleted uranium contamination in Colonie, NY, USA
Lloyd, N.S.; Chenery, S.R.N.; Parrish, R.R.. 2009 The distribution of depleted uranium contamination in Colonie, NY, USA. Science of the Total Environment, 408 (2). 397-407. 10.1016/j.scitotenv.2009.09.024Before downloading, please read NORA policies.
Uranium oxide particles were dispersed into the environment from a factory in Colonie (NY, USA) by prevailing winds during the 1960’s and ’70’s. Uranium concentrations and isotope ratios from bulk soil samples have been accurately measured using inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) without the need for analyte separation chemistry. The natural range of uranium concentrations in the Colonie soils has been estimated as 0.7 – 2.1 μg g-1, with a weighted geometric mean of 1.05 ± 0.06 μg g 1; the contaminated soil samples comprise uranium up to 500 ± 40 μg g-1. A plot of 236U/238U against 235U/238U isotopes ratios describes a mixing line between natural uranium and depleted uranium (DU) in bulk soil samples; scatter from this line can be accounted for by heterogeneity in the DU particulate. The end-member of DU compositions aggregated in these bulk samples comprises (2.05 ± 0.06) x10-3 235U/238U, (3.2 ± 0.1) x10-5 236U/238U, and (7.1 ± 0.3) x10-6 234U/238U. The analytical method is sensitive to as little as 50 ng g-1 DU mixed with the natural uranium occurring in these soils. The contamination footprint has been mapped northward from site, and at least one third of the uranium in a soil sample from the surface 5 cm, collected 5.1 km NNW of the site, is DU. The distribution of contamination within the surface soil horizon follows a trend of exponential decrease with depth, which can be approximated by a simple diffusion model. Bioturbation by earthworms can account for dispersal of contaminant from the soil surface, in the form of primary uranium oxide particulates, and uranyl species that are adsorbed to organic matter. Considering this distribution, the total mass of uranium contamination emitted from the factory is estimated to be c. 4.8 tonnes.
|Programmes:||BGS Programmes 2009 > NERC Isotope Geoscience Laboratory|
|Additional Keywords:||depleted uranium, DU, particulate, isotope ratio, ICP-MS|
|NORA Subject Terms:||Earth Sciences|
|Date made live:||22 Dec 2009 16:37|
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