Interaction between Marine Humic Matter and Polycyclic Aromatic Hydrocarbons in Lower Cook Inlet and Port Valdez, Alaska

Humic acid is a major component of naturally occurring organic matter; it interacts strongly with organic pollutants including polycyclic aromatic hydrocarbons (PAH), a class of organic pollutants present in petroleum and associated with significant long-term environmental and human health problems. The chemical associations resulting from the interaction between humic acid and PAH influence the fate and effects of PAH which are of great concern in coastal regions such as Cook Inlet, Alaska, where petroleum production and transportation coexist with renewable resources and environmental values. This project investigated the interaction of PAH and marine humic acid from sediments of Lower Cook Inlet and Port Valdez, Alaska, in an attempt to understand how and to what extent the molecular character of humic acid from these sediments influences their ability to adsorb PAH. Geochemical characterization of sediments and humic acids from the study area showed that their chemical composition is non-uniform, probably reflecting differences in both source materials and post-depositional alterations. This result indicates that the measured concentrations of PAH are largely unrelated to the properties of the humic acid from the same sediments. It is more likely that the amounts of PAH to which the sediments are exposed control observed concentrations.