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Geochemistry and solid-phase association of chromium in sediment from the Calcasieu River and estuary, Louisiana, U.S.A.

Chemical Geology

By:
, , and
DOI: 10.1016/0009-2541(94)90161-9

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Abstract

Sediment samples were collected from the lower Calcasieu River and estuary, Louisiana, in a study of the release of metals from sediments to the overlying water column. Whole samples were characterized by analyses that included: (1) determination of total sediment ammonium concentrations; (2) determination of total sediment Cr, Mn and Fe concentrations; (3) extraction of sediment with hydrogen peroxide followed by dilute hydrochloric acid to obtain recoverable metals, including oxides; and (4) extraction of sediment with hydrogen peroxide plus pyrophosphate at a pH of 7-8 to recover organically-bound Cr but not metal oxides. Concentrations of Cr, Mn and Fe in sediment interstitial water were determined. The concentrations of Cr in interstitial water could not be predicted from total sediment concentrations of Cr. Degradation of organic matter appeared to be the mechanism that caused elevated Cr concentrations in the interstitial water. Concentrations of Cr in interstitial water were positively correlated with total concentrations of ammonium in sediment. Concentrations of Cr in interstitial water that exceeded water-column concentrations of Cr were found when the total concentrations of ammonium in sediment exceeded 1 ??mol per gram wet weight. Concentrations of metals in interstitial water that are larger than metal concentrations in the water column create a potential for diffusive flux and metal enrichment of the overlying water column. ?? 1994.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Geochemistry and solid-phase association of chromium in sediment from the Calcasieu River and estuary, Louisiana, U.S.A.
Series title:
Chemical Geology
DOI:
10.1016/0009-2541(94)90161-9
Volume
116
Issue:
1-2
Year Published:
1994
Language:
English
Publisher:
Elsevier
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Chemical Geology
First page:
123
Last page:
135