A model of the oxidation of iron and cadmium sulfide in sediments

Journal Article · Sun Dec 01 04:00:00 EST 1996 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1002/etc.5620151212· OSTI ID:483689

Toro, D.M. di ^[1]; Mahony, J D ^[1]; Hansen, D J; Berry, W J ^[2]

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1. Manhattan Coll., New York, NY (United States). Environmental Engineering Dept.
2. Environmental Protection Agency, Narragansett, RI (United States)

A model is presented for the temporal and vertical variation of acid-volatile sulfide (AVS), simultaneously extracted cadmium (SEM{sub Cd}), and cadmium interstitial water concentration in sediments. The model is based on the one-dimensional advective-dispersive mass balance equation. Transport by particle and pore-water mixing is considered. The state variable include the components of AVS and SEM{sub Cd}, namely iron sulfide (FeS) and cadmium sulfide (CdS), and sorbed + pore-water cadmium (Cd{sub T}). In addition, particulate organic carbon (POC), iron oxyhydroxide, and dissolved oxygen are explicitly modeled. The oxidation, displacement, and partitioning reactions that are sources and sinks of the state variables are included. The model is applied to three experimental data sets. Two of these employed marine sediments with typical organic carbon and AVS concentrations. The third employed a freshwater sediment with a high POC and low AVS. The calibration produced similar partitioning parameters on an organic carbon basis for both sediments. However, the oxidation and partitioning behavior of the FeS in the low AVS freshwater sediment was distinctly different from the high AVS cases. The model successfully reproduces the major features of the experimental data: the progressive decrease in AVS and SEM{sub Cd}, and an increase in the SEM{sub Cd} to AVS ratio in the surface layers. It is less successful in reproducing the pore-water cadmium concentrations.

• Sponsoring Organization: USDOE
• OSTI ID: 483689
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 12 Vol. 15; ISSN ETOCDK; ISSN 0730-7268
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CADMIUM SULFIDES
ENVIRONMENTAL TRANSPORT
INTERSTITIAL WATER
IRON SULFIDES
MATHEMATICAL MODELS
OXIDATION
SEASONAL VARIATIONS
SEDIMENTS
WATER CHEMISTRY