Trophic Magnification of PCBs and Its Relationship to the Octanol−Water Partition Coefficient

• Published in: Environmental science & technology 2011-05, Vol.45 (9), p.3917-3924
• Main Authors: Walters, David M, Mills, Marc A, Cade, Brian S, Burkard, Lawrence P
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Aquatic life; Bioaccumulation; Biological and medical sciences; Ecotoxicology, biological effects of pollution; Environmental Processes; Fishes - metabolism; Food Chain; Food chains; Fresh Water - analysis; Fundamental and applied biological sciences. Psychology; General aspects; Geologic Sediments - analysis; Lakes; Models, Biological; Octanols - chemistry; PCB; Phytoplankton - metabolism; Plankton - metabolism; Polychlorinated biphenyls; Polychlorinated Biphenyls - analysis; South Carolina; Studies; Water - chemistry; Zooplankton - metabolism
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es103158s

We investigated polychlorinated biphenyl (PCB) bioaccumulation relative to octanol−water partition coefficient (K OW) and organism trophic position (TP) at the Lake Hartwell Superfund site (South Carolina). We measured PCBs (127 congeners) and stable isotopes (δ15N) in sediment, organic matter, phytoplankton, zooplankton, macroinvertebrates, and fish. TP, as calculated from δ15N, was significantly, positively related to PCB concentrations, and food web trophic magnification factors (TMFs) ranged from 1.5−6.6 among congeners. TMFs of individual congeners increased strongly with log K OW, as did the predictive power (r 2) of individual TP-PCB regression models used to calculate TMFs. We developed log K OW-TMF models for eight food webs with vastly different environments (freshwater, marine, arctic, temperate) and species composition (cold- vs warmblooded consumers). The effect of K OW on congener TMFs varied strongly across food webs (model slopes 0.0−15.0) because the range of TMFs among studies was also highly variable. We standardized TMFs within studies to mean = 0, standard deviation (SD) = 1 to normalize for scale differences and found a remarkably consistent K OW effect on TMFs (no difference in model slopes among food webs). Our findings underscore the importance of hydrophobicity (as characterized by K OW) in regulating bioaccumulation of recalcitrant compounds in aquatic systems, and demonstrate that relationships between chemical K OW and bioaccumulation from field studies are more generalized than previously recognized.