The relative importance of manganese and iron oxides and organic matter in the sorption of trace metals by surficial lake sediments

Journal Article · Sun Mar 01 04:00:00 EST 1992 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(92)90055-N· OSTI ID:7279513

Young, L B ^[1]; Harvey, H H ^[2]

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1. Univ. of Ottawa, Ontario (Canada)
2. Univ. of Toronto, Ontario (Canada)

The sorption of trace metals (Zn, Ni, and Cu) by surficial sediments of four acid (pH < 5.6) and three circumneutral (pH 6.4-6.5) lakes were compared via distribution coefficients (K{sub D}). These were calculated from measurements of porewater metal concentrations in the uppermost layer of lake sediments and total sediment-sorped metal, as determined by the sum of the amounts of metal recovered from the easily reducible (ER) (exchangeable and bound to oxides of Mn), reducible (R) (bound to oxides of Fe), alkaline extracted (ORG) (organically bound) fractions of sediment. Porewater Cd concentrations were undetectable in all lakes. A comparison of the relative amounts of metal recovered from the three sediment components was used to illustrate differences in the partitioning of the trace metals among the seven lakes. Calculated K{sub D}s for Zn and Ni showed reduced pH dependence with decreasing lake pH. No such pH dependence was noted for Cu. The comparison of the relative amounts of metal recovered from each of the three sediment components revealed that the partitioning of the trace metals Zn, Cd, and Ni differed among the seven lakes. Based on the three sampling locations in each study lake, the authors suggest that differences in the concentration of metals in the ER vs. R and PRG sediment component in surficial sediments of recently acidified vs. circumneutral lakes may be the result of two concurrent processes: (1) a pH-dependent decrease in the sedimentation of ER metal, and (2) a concurrent pH-induced precipitation of Fe-humic complexes involving the coprecipitation of trace metals with strongly bound Fe-humic complexes.

• OSTI ID: 7279513
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 56:3; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540310* -- Environment
Aquatic-- Basic Studies-- (1990-)
ACIDIFICATION
CADMIUM
CHALCOGENIDES
CHEMISTRY
COPPER
DATA
DISTRIBUTION
ECOLOGICAL CONCENTRATION
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
IRON COMPOUNDS
IRON OXIDES
LAKES
MANGANESE COMPOUNDS
MANGANESE OXIDES
MATTER
METALS
NICKEL
NUMERICAL DATA
ORGANIC MATTER
OXIDES
OXYGEN COMPOUNDS
PH VALUE
POLLUTION
SEDIMENTS
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
SURFACE WATERS
TRACE AMOUNTS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
WATER CHEMISTRY
WATER POLLUTION
ZINC