Three-phase modeling of polycyclic aromatic hydrocarbon association with pore-water-dissolved organic carbon

Journal Article · Tue Jun 01 00:00:00 EDT 1999 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1002/etc.5620180611· OSTI ID:6481585

Mitra, S ^[1]; Dickhut, R M ^[2]

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1. Tulane Univ., New Orleans, LA (United States)
2. Virginia Inst. of Marine Science, Gloucester Point, VA (United States)

Log-log plots of measured organic carbon-normalized sediment pore-water distribution coefficients (K[prime][sub OC]s) for several polycyclic aromatic hydrocarbons (PAHs) versus their octanol-water partition coefficients (K[prime][sub OW]s) at two sites in the Elizabeth River, Virginia, show large deviations from linearity. Organic-carbon normalized distribution coefficients for these PAHs between sediments and pore waters decreased by more than two orders of magnitude with depth as well. To determine to what extent pore water dissolved and colloidal organic carbon (DOC) was responsible for the observed nonlinearity and decrease in K[prime][sub OC], a three-phase model was used to estimate pore-water PAH-DOC binding coefficients (K[sub DOC]). Partitioning of PAHs to pore-water DOC (i.e., K[sub DOC])enhances the observed dissolved phase PAH concentration, especially for high-K[sub OW] compounds, contributing to the nonlinearity in K[prime][sub OC]-K[sub OW] plots. However, the application of the three-phase partitioning model to these data indicate that, at most, pore-water PAH-DOC binding accounts for one order of magnitude of the observed decrease in K[prime][sub OC] with depth in the sediment bed. The results of this study are consistent with three-phase partitioning theory for hydrophobic organic compounds between sediment organic matter, pore-water DOC, and freely dissolved aqueous phases in natural systems.

• OSTI ID: 6481585
• Journal Information: Environmental Toxicology and Chemistry, Vol. 18:6; ISSN 0730-7268
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
INTERSTITIAL WATER
MATHEMATICAL MODELS
ORGANIC MATTER
POLYCYCLIC AROMATIC HYDROCARBONS
SEDIMENTS
WATER CHEMISTRY
WATER POLLUTION
AROMATICS
CHEMISTRY
GROUND WATER
HYDROCARBONS
HYDROGEN COMPOUNDS
MATTER
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
POLLUTION
WATER
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)