FACTORS AFFECTING PHYTOPLANKTON SPECIES-SPECIFIC DIFFERENCES IN ACCUMULATION OF 40 POLYCHLORINATED-BIPHENYLS (PCBS)

Experiments were conducted to compare the bioaccumulation of hydrophob ic compounds among different phytoplankton divisions, and to evaluate the factors that affect species-specific differences. Unialgal batch c ultures of Selenastrum capricornutum, Anabaena sp., and Synedra sp. we re exposed to 40 PCB congeners at 11 degrees C for 40 d. PCBs selected for this study represented all 10 homologs, different substitution pa tterns, and a wide range of physical-chemical properties representativ e of compounds known to bioaccumulate in aquatic organisms. Congener-s pecific partitioning into the algal phase over time was investigated. Species differences were observed in the rate and magnitude of accumul ation. For all species, a rapid association of PCBs with the algal pha se was followed by a slower partitioning from the media to the algae, which continued for several days. Bioaccumulation factors (BAFs) could be predicted from K-OW for PCB congeners with log K-OW values <6.0, w hereas no such correlation was found for the more hydrophobic congener s. Normalization of BAFs to total lipid or glycolipid content reduced some of the variability between species for the less hydrophobic conge ners, but not for the more hydrophobic congeners. Normalization of BAF s to the phospholipid fraction reduced species variability for the mor e hydrophobic congeners, supporting the hypothesis that these compound s have restricted membrane permeability.