Age-related polychlorinated biphenyl dynamics in immature bull sharks (Carcharhinus leucas)

Document Type

Article

Publication Date

1-1-2014

Publication Title

Environmental Toxicology and Chemistry

Volume

33

Issue

1

First Page

35

Keywords

Hydrophobicity, Maternal transfer, Shark liver, Umbilical scar stage, Young-of-year

Last Page

43

Abstract

Polychlorinated biphenyls (PCBs) were quantified in liver tissues of bull sharks (Carcharhinus leucas) ranging in age from <4 wk to >3 yr. Summed values of PCBs (ΣPCBs) ranged from 310ng/g to 22 070ng/g (lipid wt) across age classes with ΣPCB concentrations for the youngest sharks in the present study (<4 wk; 5230±2170ng/g lipid wt) determined to not significantly differ from those quantified in >3-yr-old sharks, highlighting the extent of exposure of this young life stage to this class of persistent organic pollutants (POPs). Age normalization of PCB congener concentrations to those measured for the youngest sharks demonstrated a significant hydrophobicity (log octanol/water partition coefficient [KOW]) effect that was indicative of maternal offloading of highly hydrophobic (logKOW ≥6.5) congeners to the youngest individuals. A distinct shift in the PCB congener profiles was also observed as these young sharks grew in size. This shift was consistent with a transition from the maternally offloaded signal to the initiation of exogenous feeding and the contributions of mechanisms including growth dilution and whole-body elimination. These results add to the growing pool of literature documenting substantially high concentrations of POPs in juvenile sharks that are most likely attributable to maternal offloading. Collectively, such results underscore the potential vulnerability of young sharks to POP exposure and pose additional concerns for shark-conservation efforts. © 2013 SETAC.

DOI

10.1002/etc.2402

ISSN

07307268

E-ISSN

15528618

PubMed ID

24357032

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