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) : Gustafsson, Orjan

PDF Url : ADA327841

Report Date : FEB 1997

Pagination or Media Count : 312

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 (238)U-234Th disequilibria, indicating a western North Atlantic pyrene sink corresponding to about 50% of emissions from the region's 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

Distribution Statement : APPROVED FOR PUBLIC RELEASE