Bioaccumulation and air-water exchange of the PAH phenanthrene in phytoplankton and Raritan Bay, New Jersey

In order to improve the understanding of the interactions between bioaccumulation in phytoplankton and air-water exchange of polycyclic aromatic hydrocarbons (PAHs) in the NY/NJ Hudson River Harbor Estuary, the accumulation kinetics of the common PAH phenanthrene was studied in two species of coastal diatoms, Thalassiosira weissflogii and T. pseudonana, using a two-compartment kinetics bioaccumulation model. This model coupled with air-water exchange and sedimentation processes was then applied to field data from Raritan Bay, collected during four cruises from April 2000 to April 2001.; The bioaccumulation kinetics parameters of phenanthrene in the two species of coastal diatoms were measured in laboratory experiments using 14 C-labeled phenanthrene. The accumulation of phenanthrene in these diatoms follows a two-compartment mechanism, which includes fast surface sorption and subsequent accumulation into the cell's interior.; Field measurements of dissolved And particulate phenanthrene concentrations in Raritan Bay suggest the presence of a particulate phase (possible soot particles) to which PAHs sorbed more strongly compared to organic carbon. Using an extended soot carbon-partitioning equation, a small fraction (5–10%) of particulate phenanthrene was estimated to be associated with organic carbon in the suspended particle phase, suggesting the predominance of the soot-like phase for PAHs, such as phenanthrene, methylphenanthrenes, and pyrene, in Raritan Bay.; A dynamic model that coupled air-water exchange and phytoplankton accumulation of phenanthrene was applied to field data from Raritan Bay, New Jersey, to investigate the mutual interactions of the two processes. Annual dynamic simulations show that using a monthly collected database from a nearby shore site (Sandy Hook, New Jersey) for gas phase concentrations of phenanthrene as input provides a better prediction of dissolved phase concentrations than seasonal over-water measurements. This modeling results suggest that processes such as horizontal air and water movements may maintain disequilibria between air, water, and suspended particles phases for hydrophobic organic pollutants.