Iron oxide forms and heavy metal transformations in sulfaquepts in Baltimore Harbor dredged materials

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6653723

El-Desoky, M A

In contract to many soils, acid ammonium oxalate extractable Fe (Fe{sub o}) was commonly greater than dithionite extractable Fe (Fe{sub d}) in samples of these soils. Apparently as a result of lateral Fe movement, the upper part of one profile contained up to 165 g/kg of total Fe and 122 g/kg of oxalate extractable Fe. Experiments showed that the high Fe{sub o}/Fe{sub d} ratios in these soils may be related to their high organic matter and ferrous-Fe contents as well as to poor crystallinity of Fe oxides and extraction of jarositic Fe of the oxidized zone and Fe monosulfides from reduced zone samples by oxalate with these soils. An incubation experiment was conducted to identify effects of temperature, shaking conditions, and time on the extractability of Fe, Mn, Zn, Cu, Cr, Ni, Pb, and Cd forms in samples from oxidized and reduced zones of the higher elevation profile. Sequential extractions of water (soluble), DTPA (exchangeable and organically complexes), acid ammonium oxalate (Fe oxide associated), and H{sub 2}O{sub 2} (sulfide-bound) were used. As evidence by slight decrease in pH with time and shaking and the presence of some H{sub 2}O{sub 2} extractable metals, the oxidized zone apparently still contains some sulfide-bound metals. Water soluble contents of Mn, Cr, Ni, Pb, and Cd of shaken-reduced zone samples increased with time. Water soluble Mn and Cd in these samples increased from 54 and 0.010 mg/kg to 654 and 0.127 mg/kg, respectively, when they were incubated at 32 C for 7 weeks. Sulfide-bound metals of reduced zone samples transformed to mobile and Fe oxide associated forms with shaking and time. Sulfide-bound Mn under these conditions converted mainly to mobile forms and partly to Fe oxide associated forms.

• Research Organization: Maryland Univ., College Park, MD (USA)
• OSTI ID: 6653723
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540210* -- Environment
Terrestrial-- Basic Studies-- (1990-)
CADMIUM
CHALCOGENIDES
CHEMISTRY
CHROMIUM
COPPER
ELEMENTS
ENVIRONMENTAL TRANSPORT
EXTRACTION
FEDERAL REGION III
HARBORS
IRON
IRON COMPOUNDS
IRON OXIDES
LEAD
MANGANESE
MARYLAND
MASS TRANSFER
METALS
NICKEL
NORTH AMERICA
ORGANIC MATTER
OXIDES
OXYGEN COMPOUNDS
PH VALUE
QUANTITY RATIO
SEDIMENTS
SEPARATION PROCESSES
SOIL CHEMISTRY
SOLUBILITY
SULFIDES
SULFUR COMPOUNDS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
USA
ZINC