Release of nutrients and metals following oxidation of freshwater and saline sediment

Journal Article · · J. Environ. Qual.; (United States)

OSTI ID:5710493

Delaune, R D; Smith, C J

Mississippi River deltaic sediments were collected from freshwater and adjacent saline environments along Louisiana's Gulf Coast to evaluate chemical changes that may develop when bottom sediment from different salinity regimes with contrasting levels of reduced S are exposed to anoxic environment. Chemical transformations of the dredged sediments were influenced by changes in the sediment-water pH and oxidation-reduction status. Sediment pH decreased as the redox potential (Eh) was increased in both the freshwater and saline sediment. Both sediments had near-neutral pH when maintained under anoxic conditions and the minimum pH developed under oxic conditions was 5.1 and 3.0 for the freshwater and saline sediment resulted in the release of the potentially toxic metals Pb, Cu, Ni, Cr, Cd, and Sb into the solution. There was also an increase in the solution concentration of Fe, Mn, Al, and Se. The solution concentration of these elements was inversely proportional Eh (P less than or equal to 0.05). The freshwater sediment when exposed to oxic conditions showed no increase in the solution concentrations of these elements. Results suggest that the concentration of reduced S in anoxic dredged sediment along other areas of the Gulf Coast should be closely evaluated in relation to potential acidity before subjected to upland disposal.

• Research Organization: Louisiana State Univ., Baton Rouge
• OSTI ID: 5710493
• Journal Information: J. Environ. Qual.; (United States), Journal Name: J. Environ. Qual.; (United States) Vol. 14:2; ISSN JEVQA
• Country of Publication: United States
• Language: English

Related Subjects

520200* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALUMINIUM
ANTIMONY
CADMIUM
CHEMICAL REACTIONS
CHROMIUM
COPPER
DREDGING
ECOLOGICAL CONCENTRATION
ELEMENTS
FEDERAL REGION VI
FRESH WATER
GULF COAST
HYDROGEN COMPOUNDS
INTERFACES
IRON
LEAD
LOUISIANA
MANGANESE
METALS
NICKEL
NONMETALS
NORTH AMERICA
NUTRIENTS
OXIDATION
OXYGEN COMPOUNDS
PH VALUE
REDOX POTENTIAL
SALINITY
SEDIMENT-WATER INTERFACES
SEDIMENTS
SELENIUM
SEMIMETALS
SULFUR
TRANSFORMATIONS
TRANSITION ELEMENTS
USA
WATER