Factors affecting phytoplankton species-specific differences in accumulation of 40 polychlorinated biphenyls (PCBs)

Abstract

Abstract Experiments were conducted to compare the bioaccumulation of hydrophobic compounds among different phytoplankton divisions, and to evaluate the factors that affect species-specific differences. Unialgal batch cultures of Selenastrum capricornutum, Anabaena sp., and Synedra sp. were exposed to 40 PCB congeners at 11°C for 40 d. PCBs selected for this study represented all 10 homologs, different substitution patterns, and a wide range of physical-chemical properties representative of compounds known to bioaccumulate in aquatic organisms. Congener-specific partitioning into the algal phase over time was investigated. Species differences were observed in the rate and magnitude of accumulation. For all species, a rapid association of PCBs with the algal phase was followed by a slower partitioning from the media to the algae, which continued for several days. Bioaccumulation factors (BAFs) could be predicted from Kow for PCB congeners with log Kow values <6.0, whereas no such correlation was found for the more hydrophobic congeners. Normalization of BAFs to total lipid or glycolipid content reduced some of the variability between species for the less hydrophobic congeners, but not for the more hydrophobic congeners. Normalization of BAFs to the phospholipid fraction reduced species variability for the more hydrophobic congeners, supporting the hypothesis that these compounds have restricted membrane permeability.