Potential contaminants at a dredged spoil placement site, Charles City County, Virginia, as revealed by sequential extraction.
Autor: | Tang J; Department of Ocean, Earth & Atmospheric Sciences, Old Dominion University, Norfolk, Virginia 23529-0267., Whittecar GR; Department of Ocean, Earth & Atmospheric Sciences, Old Dominion University, Norfolk, Virginia 23529-0267., Johannesson KH; Department of Geology, The University of Texas at Arlington, Arlington, Texas 76019-0049., Daniels WL; Department of Crop and Soil Environmental Sciences, Virginia Polytechnic Institute and State University, 244 Smyth Hall, Blacksburg, Virginia 24061-0404. |
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Jazyk: | angličtina |
Zdroj: | Geochemical transactions [Geochem Trans] 2004 Dec 07; Vol. 5 (4), pp. 49. Date of Electronic Publication: 2004 Dec 07 (Print Publication: 2004). |
DOI: | 10.1186/1467-4866-5-49 |
Abstrakt: | Backfills of dredged sediments onto a former sand and gravel mine site in Charles City County, VA may have the potential to contaminate local groundwater. To evaluate the mobility of trace elements and to identify the potential contaminants from the dredged sediments, a sequential extraction scheme was used to partition trace elements associated with the sediments from the local aquifer and the dredged sediments into five fractions: exchangeable, acidic, reducible, oxidizable, and residual phases. Sequential extractions indicate that, for most of the trace elements examined, the residual phases account for the largest proportion of the total concentrations, and their total extractable fractions are mainly from reducible and oxidizable phases. Only Cd, Pb, and Zn have an appreciable extractable proportion from the acidic phase in the filled dredged sediments. Our groundwater monitoring data suggest that the dredged sediments are mainly subject to a decrease in p H and a series of oxidation reactions, when exposed to the atmosphere. Because the trace elements released by carbonate dissolution and the oxidation (e.g., organic matter degradation, iron sulfide and, ammonia oxidation) are subsequently immobilized by sorption to iron, manganese, and aluminum oxides, no potential contaminants to local groundwater are expected by addition of the dredged sediments to this site. (Copyright © 2004 American Institute of Physics.) |
Databáze: | MEDLINE |
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