Sites in the United States Contaminated with Radioactivity

Wolbarst, Anthony B.; Blom, Phenyo; Chan, Derek; Cherry, R.N.; Doehnert, M.; Fauver, D.N.; Hull, Harry Blair; MacKinney, John; Mauro, John; Richardson, A.C.B.; Zaragoza, Luis

doi:10.1097/00004032-199909000-00002

Cited by 9 publications

(2 citation statements)

References 2 publications

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“…Contamination of groundwater and soil with uranium has resulted from anthropogenic activities such as uranium mining and milling and processing of uranium for nuclear weapons and energy programs [ Wolbarst et al ., ; National Research Council (NRC) , ], as well as from natural processes in rock, soil, and water. Uranium contamination causes health risks and presents serious public health concerns [ Zimmerman et al ., ; NRC , ].…”

Section: Introductionmentioning

confidence: 99%

Pore‐scale evaluation of uranyl phosphate precipitation in a model groundwater system

Fanizza

Yoon

Zhang

et al. 2013

Water Resources Research

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[1] The abiotic precipitation of uranium (U(VI)) was evaluated in a microfluidic pore network (i.e., micromodel) to assess the efficacy of using a phosphate amendment to immobilize uranium in groundwater. U(VI) was mixed transverse to the direction of flow with hydrogen phosphate (HPO 4 2À ), in the presence or absence of calcium (Ca 2þ ) or sulfate (SO 4 2À ), in order to identify precipitation rates, morphology and types of minerals formed, and effects of mineral precipitates on pore blockage. Precipitation occurred over the time scale of hours to days. Relative to when only U(VI) and HPO 4 2À were present, precipitation rates were 2.3 times slower when SO 4 2À was present, and 1.4 times faster when Ca 2þ was present; larger crystals formed in the presence of SO 4 2À. Raman backscattering spectroscopy and micro-X-ray diffraction results both showed that the only mineral precipitated was chernikovite, UO 2 HPO 4 Á 4H 2 O; energy dispersive X-ray spectroscopy results indicate that Ca and S are not incorporated into the chernikovite lattice. A pore-scale model was developed, and simulation results of saturation ratio (SR ¼ Q/K sp ) suggest that chernikovite is the least thermodynamically favored mineral to precipitate (0 < SR < 1) compared to uranyl hydrogen phosphate and Na-autunite (13 < SR < 40), and uranyl orthophosphate and Ca-autunite (when Ca 2þ is present; SR > 10 5 ). Fluorescent tracer studies and laser confocal microscopy images showed that densely aggregated precipitates blocked pores and reduced permeability. The results suggest that uranium precipitation with phosphate as chernikovite is rapid on the time scale of remediation for the conditions considered and can block pores, alter fluid flow paths, and potentially limit mixing and precipitation.

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Section: Introductionmentioning

confidence: 99%

Pore‐scale evaluation of uranyl phosphate precipitation in a model groundwater system

Fanizza

Yoon

Zhang

et al. 2013

Water Resources Research

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“…Metal contamination of soil and groundwater is a persistent problem at hundreds of sites across the United States where uranium was mined or processed, or nuclear research was conducted (Riley & Zachara, 1992; Wolbarst et al ., 1999). Engineered remedial actions (i.e., capping, soil excavation, groundwater pump and treat) are often necessary for containment and treatment of source zone areas that have high contaminant concentrations, but more passive, cost‐effective technologies are of great interest for widespread peripheral areas that have lower contaminant concentrations.…”

Section: Introductionmentioning

confidence: 99%

Effects of legacy nuclear waste on the compositional diversity and distributions of sulfate-reducing bacteria in a terrestrial subsurface aquifer

Bagwell¹,

Liu²,

Wu³

et al. 2006

FEMS Microbiology Ecology

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The impact of legacy nuclear waste on the compositional diversity and distribution of sulfate-reducing bacteria in a heavily contaminated subsurface aquifer was examined. dsrAB clone libraries were constructed and restriction fragment length polymorphism (RFLP) analysis used to evaluate genetic variation between sampling wells. Principal component analysis identified nickel, nitrate, technetium, and organic carbon as the primary variables contributing to well-to-well geochemical variability, although comparative sequence analysis showed the sulfate-reducing bacteria community structure to be consistent throughout contaminated and uncontaminated regions of the aquifer. Only 3% of recovered dsrAB gene sequences showed apparent membership to the Deltaproteobacteria. The remainder of recovered sequences may represent novel, deep-branching lineages that, to our knowledge, do not presently contain any cultivated members; although corresponding phylotypes have recently been reported from several different marine ecosystems. These findings imply resiliency and adaptability of sulfate-reducing bacteria to extremes in environmental conditions, although the possibility for horizontal transfer of dsrAB is also discussed.

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Bibliographie

2003

Radioaktivität in Lebensmitteln

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Sites in the United States Contaminated with Radioactivity

Cited by 9 publications

References 2 publications

Pore‐scale evaluation of uranyl phosphate precipitation in a model groundwater system

Pore‐scale evaluation of uranyl phosphate precipitation in a model groundwater system

Effects of legacy nuclear waste on the compositional diversity and distributions of sulfate-reducing bacteria in a terrestrial subsurface aquifer

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