期刊
ENVIRONMENTAL POLLUTION
卷 220, 期 -, 页码 873-881出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.envpol.2016.10.071
关键词
Uranium; Sorption; Distribution or partition coefficients; Sediment; Windermere humic aqueous model; WHAM; Speciation
资金
- University of Saskatchewan Toxicology Centre partly through the NSERC CREATE HERA Training Program [3712302010]
- AREVA Resources Canada Inc. [6500024810]
Uranium (U) can enter aquatic environments from natural and anthropogenic processes, accumulating in sediments to concentrations that could, if bioavailable, adversely affect benthic organisms. To better predict the sorption and mobility of U in aquatic ecosystems, we investigated the sediment-solution partition coefficients (K-d) of U for nine uncontaminated freshwater sediments with a wide range of physicochemical characteristics over an environmentally relevant pH range. Test solutions were reconstituted to mimic water quality conditions and U(VI) concentrations (0.023-2.3 mg U/L) found downstream of Canadian U mines. Adsorption of U(VI) to each sediment was greatest at pH 6 and 7, and significantly reduced at pH 8. There were significant differences in pH-dependent sorption among sediments with different physicochemical properties, with sorption increasing up until thresholds of 12% total organic carbon, 37% fine fraction (<= 50 mu m), and 29 g/kg of iron content. The Kd values for U(VI) were predicted using the Windermere Humic Aqueous Model (WHAM) using total U(VI) concentrations, and water and sediment physicochemical parameters. Predicted K-d-U values were generally within a factor of three of the observed values. These results improve the understanding and assessment of U sorption to field sediment, and quantify the relationship with sediment properties that may influence the bioavailability and ecological risk of U-contaminated sediments. (C) 2016 Elsevier Ltd. All rights reserved.
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