HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Related articles in JEQ Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (11) Citing Articles via Google Scholar Google Scholar Articles by Sowder, A. G. Articles by Morris, P. J. Search for Related Content PubMed PubMed Citation Articles by Sowder, A. G. Articles by Morris, P. J. GeoRef GeoRef Citation Agricola Articles by Sowder, A. G. Articles by Morris, P. J. Related Collections Mixed Wastes Radionuclides Heavy Metals

Partitioning and Availability of Uranium and Nickel in Contaminated Riparian Sediments

^a Savannah River Ecology Laboratory, The Univ. of Georgia, Drawer E, Aiken, SC 29802
^b Marine Biomedicine and Environmental Sciences, Medical Univ. of South Carolina, Charleston, SC 29425

View larger version (33K): [in a new window]   Fig. 1. Savannah River Site (SRS) and study site location map. The SRS lies in the upper Atlantic Coastal Plain along the Savannah River in South Carolina. Past discharges of process wastewater to Tims Branch resulted in extensive contamination of sediments downstream from the M-Area sewer outfall, including sediments within the Steed Pond basin. Sediment sampling locations for Steed Pond (SP) and uncontaminated reference sites, that is, upper Tims Branch (TB00) and Boggy Gut (BG), are indicated on the SRS map and M-Area inset.

View larger version (45K): [in a new window]   Fig. 2. Distribution of (a) U and (b) Ni in whole, sand, and water-dispersible silt and clay fractions of SP2B1 (12.7 g kg-1 sediment organic carbon [SOC]) and SP5B1 (82.2 g kg-1 SOC). Error bars are one standard deviation (n = 3). Significantly different means ( = 0.05) are distinguished by lowercase letters for SP2B1 distributions as determined by one-way analysis of variance and post hoc mean comparisons using Tukey and Scheffe tests. Uranium and nickel distributions in SP5B1 are not significantly different among the four size fractions. Legend applies to both graphs.

View larger version (150K): [in a new window]   Fig. 3. (a) Scanning electron microscope (SEM) image with corresponding energy dispersive X-ray (EDX) spectra of representative clay sized particles in SP1B1 clay size fraction. Region "Fe" illustrates a typical iron-oxide coating with substitution of Ti and Mn. Region "k" corresponds to underlying kaolinite matrix. (b) SEM image of a large aggregate encountered in SP2B1 water-dispersible silt fraction. (c) SEM image of a Ni phase with Cu- and Ni-rich region indicated. Both metals are anthropogenic in origin. Phases such as this one may represent source term artifacts, surviving decades of weathering, or the resulting secondary weathering products.

View larger version (36K): [in a new window]   Fig. 4. Ratio of metals concentrations in ammonium oxalate (AO) and citrate–dithionite (CD) extractions for (a) Fe, Mn, and Ti and (b) Al as the chief constituents of upland soil and Steed Pond sediment coatings. Error bars are one standard deviation (n = 3).

View larger version (32K): [in a new window]   Fig. 5. Comparison of sequential extraction profiles performed with and without hydroxylamine–HCl (HA) for (a) U and (b) Ni. Arrows indicate apparent redistributions of U and Ni to subsequent extraction stages following omission of HA step. Sequential extractions with HA step were performed in duplicate only (n = 2). Cumulative metal concentrations extracted are presented in Table 6. Error bars are one standard deviation (n = 3) for non-HA sequential extraction. Legend applies to both graphs.

View larger version (25K): [in a new window]   Fig. 6. Sequential extraction results for Steed Pond sediments for (a) U, (b) Ni, (c) Fe, (d) Mn, and (e) Al. Sequential extractions were performed without hydroxylamine–HCl (HA) step. Data columns within each sequential extraction fraction are presented by increasing sediment organic carbon content (i.e., SP2B1, SP1B2, SP1B1, and SP5B1). Cumulative metal concentrations extracted are presented in Table 6. Error bars are one relative standard deviation (n = 3). Legend applies to all graphs.