Physico-Chemical Speciation and Ocean Fluxes of Polycyclic Aromatic Hydrocarbons.

Partitioning of ecotoxicologically significant polycyclic aromatic hydrocarbons (PAHs) to non-aqueous, particularly colloidal and soot, phases results in a decrease in their, directly bioavailable, dissolved fractions. Functionally distinguishing colloidal sorbents from dissolved entities as constit...

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Bibliographic Details
Main Author: Gustafsson, Orjan
Other Authors: MASSACHUSETTS INST OF TECH CAMBRIDGE
Format: Text
Language:English
Published: 1997
Subjects:
Organic Chemistry
Physical Chemistry
Physical and Dynamic Oceanography
*FLUX(RATE)
*AROMATIC HYDROCARBONS
*OCEANS
*PHYSICOCHEMICAL PROPERTIES
*POLYCYCLIC COMPOUNDS
SOOT
COASTAL REGIONS
DISPERSING
FLUORESCENCE
OCEAN SURFACE
MODELS
THESES
CARBON
QUENCHING
SURFACES
CONTINENTAL SHELVES
VERTICAL ORIENTATION
ABSORBERS(MATERIALS)
ORGANIC MATERIALS
MACROMOLECULES
HORIZONTAL ORIENTATION
COLLOIDS
SEDIMENTS
BAYS
ULTRAFILTRATION
*SPECIATION
ECOTOXICOLOGY
BIOAVAILABILITY
SORBENTS
PARTION COEFFICIENTS
AQUEOUS SOLUTIONS
North Atlantic
Online Access:http://www.dtic.mil/docs/citations/ADA327841
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA327841
Description
Summary:Partitioning of ecotoxicologically significant polycyclic aromatic hydrocarbons (PAHs) to non-aqueous, particularly colloidal and soot, phases results in a decrease in their, directly bioavailable, dissolved fractions. Functionally distinguishing colloidal sorbents from dissolved entities as constituents that provide a molecular milieu into and onto which chemicals can escape from the aqueous solution, implies that non all macromolecules can act as sorbents. Thus, instead of ultrafiltration, less invasive time-resolved fluorescence quenching experiments revealed that coastal colloids exhibit a factor of five-to-ten lower sorbent efficiencies, on an organic-carbon basis, than sedimentary organic matter. PAH concentrations in continental shelf surface sediments could be explained with the soot carbon concentrations (r2-0.97-0.99) while they were not correlated with non-soot organic carbon at the 95% confidence level. Theoretically estimated soot-water partion coefficients, assuming sorbate-soot interaction is thermodynamically similar to sorbate fusion, are suggesting a soot sorption strength 100 times greater than for non-soot organic matter (carbon basis). Exponentially decreasing surface ocean fluxes of PAHs away from northeastern USA was demonstrated using (238)U-234Th disequilibria, indicating a western North Atlantic pyrene sink corresponding to about 50% of emissions from the region's coastal states.

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