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Quantifying uranium complexation by groundwater dissolved organic carbon using asymmetrical flow field-flow fractionation.
J Contam Hydrol. 2007 May 14; 91(3-4):233-46.JC

Abstract

The long-term mobility of actinides in groundwaters is important for siting nuclear waste facilities and managing waste-rock piles at uranium mines. Dissolved organic carbon (DOC) may influence the mobility of uranium, but few field-based studies have been undertaken to examine this in typical groundwaters. In addition, few techniques are available to isolate DOC and directly quantify the metals complexed to it. Determination of U-organic matter association constants from analysis of field-collected samples compliments laboratory measurements, and these constants are needed for accurate transport calculations. The partitioning of U to DOC in a clay-rich aquitard was investigated in 10 groundwater samples collected between 2 and 30 m depths at one test site. A positive correlation was observed between the DOC (4-132 mg/L) and U concentrations (20-603 microg/L). The association of U and DOC was examined directly using on-line coupling of Asymmetrical Flow Field-Flow Fractionation (AsFlFFF) with UV absorbance (UVA) and inductively coupled plasma-mass spectrometer (ICP-MS) detectors. This method has the advantages of utilizing very small sample volumes (20-50 microL) as well as giving molecular weight information on U-organic matter complexes. AsFlFFF-UVA results showed that 47-98% of the DOC (4-136 mg C/L) was recovered in the AsFlFFF analysis, of which 25-64% occurred in the resolvable peak. This peak corresponded to a weight-average molecular weight of about 900-1400 Daltons (Da). In all cases, AsFlFFF-ICP-MS suggested that<or=2% of the U, likely present as U(VI), was complexed with the DOC. This result was in good agreement with the U speciation modeling performed on the sample taken from the 2.3 m depth, which predicted approximately 3% DOC-complexed U. This good agreement suggests that the AsFlFFF-ICP-MS method may be very useful for determining U-organic matter association in small volume samples. Because the pH (7.0-8.1) and carbonate concentrations of these waters are typical of many groundwaters, these data suggested that facilitated transport of U by DOC may be limited in its importance in many groundwater systems.

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Authors+Show Affiliations

Ranville JF
Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, United States. jranville@mines.edu
Hendry MJ
No affiliation info available
Reszat TN
No affiliation info available
Xie Q
No affiliation info available
Honeyman BD
No affiliation info available

MeSH

BenzopyransFractionation, Field FlowFresh WaterMass SpectrometrySaskatchewanUraniumWater Pollutants, Radioactive

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

17196707

Citation

Ranville, James F., et al. "Quantifying Uranium Complexation By Groundwater Dissolved Organic Carbon Using Asymmetrical Flow Field-flow Fractionation." Journal of Contaminant Hydrology, vol. 91, no. 3-4, 2007, pp. 233-46.
Ranville JF, Hendry MJ, Reszat TN, et al. Quantifying uranium complexation by groundwater dissolved organic carbon using asymmetrical flow field-flow fractionation. J Contam Hydrol. 2007;91(3-4):233-46.
Ranville, J. F., Hendry, M. J., Reszat, T. N., Xie, Q., & Honeyman, B. D. (2007). Quantifying uranium complexation by groundwater dissolved organic carbon using asymmetrical flow field-flow fractionation. Journal of Contaminant Hydrology, 91(3-4), 233-46.
Ranville JF, et al. Quantifying Uranium Complexation By Groundwater Dissolved Organic Carbon Using Asymmetrical Flow Field-flow Fractionation. J Contam Hydrol. 2007 May 14;91(3-4):233-46. PubMed PMID: 17196707.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Quantifying uranium complexation by groundwater dissolved organic carbon using asymmetrical flow field-flow fractionation. AU - Ranville,James F, AU - Hendry,M Jim, AU - Reszat,Thorsten N, AU - Xie,Qianli, AU - Honeyman,Bruce D, Y1 - 2006/12/29/ PY - 2004/08/20/received PY - 2006/08/04/revised PY - 2006/11/12/accepted PY - 2007/1/2/pubmed PY - 2007/6/15/medline PY - 2007/1/2/entrez SP - 233 EP - 46 JF - Journal of contaminant hydrology JO - J Contam Hydrol VL - 91 IS - 3-4 N2 - The long-term mobility of actinides in groundwaters is important for siting nuclear waste facilities and managing waste-rock piles at uranium mines. Dissolved organic carbon (DOC) may influence the mobility of uranium, but few field-based studies have been undertaken to examine this in typical groundwaters. In addition, few techniques are available to isolate DOC and directly quantify the metals complexed to it. Determination of U-organic matter association constants from analysis of field-collected samples compliments laboratory measurements, and these constants are needed for accurate transport calculations. The partitioning of U to DOC in a clay-rich aquitard was investigated in 10 groundwater samples collected between 2 and 30 m depths at one test site. A positive correlation was observed between the DOC (4-132 mg/L) and U concentrations (20-603 microg/L). The association of U and DOC was examined directly using on-line coupling of Asymmetrical Flow Field-Flow Fractionation (AsFlFFF) with UV absorbance (UVA) and inductively coupled plasma-mass spectrometer (ICP-MS) detectors. This method has the advantages of utilizing very small sample volumes (20-50 microL) as well as giving molecular weight information on U-organic matter complexes. AsFlFFF-UVA results showed that 47-98% of the DOC (4-136 mg C/L) was recovered in the AsFlFFF analysis, of which 25-64% occurred in the resolvable peak. This peak corresponded to a weight-average molecular weight of about 900-1400 Daltons (Da). In all cases, AsFlFFF-ICP-MS suggested that<or=2% of the U, likely present as U(VI), was complexed with the DOC. This result was in good agreement with the U speciation modeling performed on the sample taken from the 2.3 m depth, which predicted approximately 3% DOC-complexed U. This good agreement suggests that the AsFlFFF-ICP-MS method may be very useful for determining U-organic matter association in small volume samples. Because the pH (7.0-8.1) and carbonate concentrations of these waters are typical of many groundwaters, these data suggested that facilitated transport of U by DOC may be limited in its importance in many groundwater systems. SN - 0169-7722 UR - https://www.unboundmedicine.com/medline/citation/17196707/Quantifying_uranium_complexation_by_groundwater_dissolved_organic_carbon_using_asymmetrical_flow_field_flow_fractionation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0169-7722(06)00220-8 DB - PRIME DP - Unbound Medicine ER -