Black carbon in marine sediments : quantification and implications for the sorption of polycyclic aromatic hydrocarbons
Author(s)Accardi-Dey, AmyMarie, 1976-
Woods Hole Oceanographic Institution.
Philip M. Gschwend.
MetadataShow full item record
Sorption is a key factor in determining the fate of polycyclic aromatic hydrocarbons (PAHs) in the environment. Here, PAH sorption is proposed as the sum of two mechanisms: absorption into a biogenic, organic carbon (OC) fraction and adsorption onto a combustion-derived, black carbon (BC) fraction. To study BC adsorption, a 375ʻC thermal oxidation method was employed to remove OC and isolate the BC fraction. Test studies showed that nitrogen-containing macromolecules charred during this pretreatment causing a positive bias to the BC measurement. Meanwhile, the oxidation of relatively small BC particles underestimated the total BC content in non-charring samples. Models based on carbon oxidation were then proposed to estimate reasonably the total BC and OC contents of sediment samples. The adsorption of pyrene onto isolated BC particles was then studied by constructing a nonlinear isotherm, which was characterized with a BC-normalized distribution coefficient and a Freundlich exponent. Pyrene sorption to Boston Harbor sediment was then modeled as the sum of OC absorption and BC adsorption using the measured adsorption parameters and literature absorption values. Finally, literature reports of high PAH distribution coefficients from the field and nonlinear PAH isotherms from the laboratory were re-explained by considering BC adsorption.
Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering; and the Woods Hole Oceanographic Institution), 2003.Includes bibliographical references.
DepartmentJoint Program in Oceanography/Applied Ocean Science and Engineering.; Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.; Woods Hole Oceanographic Institution.
Massachusetts Institute of Technology
/Woods Hole Oceanographic Institution. Joint Program in Oceanography/Applied Ocean Science and Engineering., Civil and Environmental Engineering., Woods Hole Oceanographic Institution.