Bioconcentration of persistent organic pollutants in four species of marine phytoplankton

The uptake of polychlorinated biphenyls (PCBs) was studied in four species of marine algae. A novel experimental system to establish and maintain constant dissolved concentrations of PCBs was employed. Headspace sampling was used to verify that the freely dissolved concentrations remained constant with time. The headspace analysis also allowed sorption to dissolved organic carbon (DOC) to be quantified for all but the most lipophilic PCB congeners. Equilibration with the dissolved phase was rapid for three of the four algae species (< 1 d for the majority of congeners). Organic carbon-normalized algae/water partition coefficients (K-AlgW) were similar for three of the four species, but were lower by a factor of 10 to 20 for Phaeodactylum tricornutum. The K-AlgW values of the first three species were similar to the octanol/water partition coefficient (K-OW) for those PCB congeners for which DOC sorption could be quantified. These K-AlgW values also agreed well with organic carbon-normalized bioconcentration factors for PCBs in suspended particulate matter (BCFSPM) sampled in Baltic Sea surface water during the summer.