Corrosion and transport of depleted uranium in sand-rich environments.
The firing of depleted uranium (DU) weapons during conflicts and military testing has resulted in the deposition of DU in a variety of sand-rich environments. In this study, DU-amended dune sand microcosm and column experiments were carried out to investigate the corrosion of DU and the transport of corrosion products. Under field-moist conditions, DU corroded to metaschoepite ((UO(2))(8)O(2)(OH)(12).(H(2)O)(10)) at a rate of 0.10+/-0.012 g cm(-2)y(-1). This loosely bound corrosion product detached easily from the coupon and became distributed heterogeneously within the sand. The corrosion of DU caused significant changes in the geochemical environment, with NO(3)(-) and Fe(III) reduction observed. Column experiments showed that transport of metaschoepite was mainly dependent on its dissolution and the subsequent interaction of the resulting dissolved uranyl (UO(2)(2+)) species with sand particles. The modelling results predict that the transport of U released from metaschoepite dissolution is retarded, due to a slowly desorbing surface species (first order desorption rate constant=5.0 (+/-1.0)x10(-8)s(-1)). The concentrations of U eluting from the metaschoepite column were orders of magnitude higher than the World Health Organisation's recommended maximum admissible concentration for U in drinking water of 15 microg L(-1). Therefore, a relatively high level of mobile U contamination would be expected in the immediate proximity of a corroding penetrator in a sand-rich environment.
Biogeochemistry and Environmental Analytical Chemistry Research Group, School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK. s.handley-sidhu@bham.ac.uk
Stephanie
S
Handley-Sidhu
Nick D
ND
Bryan
Paul J
PJ
Worsfold
David J
DJ
Vaughan
Francis R
FR
Livens
Miranda J
MJ
Keith-Roach
D000327:Adsorption; D003343:Corrosion; D052918:Environmental Restoration and Remediation; D005290:Ferric Compounds / Q000737:chemistry; D009566:Nitrates / Q000737:chemistry; D012990:Soil Pollutants, Radioactive / Q000737:chemistry*; D014501:Uranium / Q000737:chemistry*
D005290:Ferric Compounds; D009566:Nitrates; D012990:Soil Pollutants, Radioactive; D014501:Uranium