Accession Number:
ADA327841
Title:
Physico-Chemical Speciation and Ocean Fluxes of Polycyclic Aromatic Hydrocarbons.
Descriptive Note:
Doctoral thesis,
Corporate Author:
MASSACHUSETTS INST OF TECH CAMBRIDGE
Personal Author(s):
Report Date:
1997-02-01
Pagination or Media Count:
312.0
Abstract:
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 238U-234Th disequilibria, indicating a western North Atlantic pyrene sink corresponding to about 50 of emissions from the regions coastal states.
Descriptors:
- *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
Subject Categories:
- Organic Chemistry
- Physical Chemistry
- Physical and Dynamic Oceanography