Complex contaminant exposure in cetaceans: A comparative E-Screen analysis of bottlenose dolphin blubber and mixtures of four persistent organic pollutants

Authors

  • Jennifer E. Yordy,

    Corresponding author
    1. Marine Biomedicine and Environmental Sciences Center, Medical University of South Carolina, Charleston, South Carolina 29412, USA
    2. National Institute of Standards and Technology, Hollings Marine Laboratory, Charleston, South Carolina 29412, USA
    • Marine Biomedicine and Environmental Sciences Center, Medical University of South Carolina, Charleston, South Carolina 29412, USA
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  • Meagan A.M. Mollenhauer,

    1. Molecular and Cell Biology Program, Medical University of South Carolina, Charleston, South Carolina 29425, USA
    2. Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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    • Deceased.

  • Rachel M. Wilson,

    1. Department of Oceanography, Florida State University, Tallahassee, Florida 32306, USA
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  • Randall S. Wells,

    1. Chicago Zoological Society c/o Mote Marine Laboratory, Sarasota, Florida 34236, USA
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  • Aleta Hohn,

    1. Southeast Fisheries Science Center, National Marine Fisheries Service, Beaufort, North Carolina 28516, USA
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  • Jay Sweeney,

    1. Dolphin Quest, 4467 Saratoga Ave, San Diego, California 93207, USA
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  • Lori H. Schwacke,

    1. Center for Human Health Risks, National Oceanic and Atmospheric Administration, Hollings Marine Laboratory, Charleston, South Carolina USA
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  • Teri K. Rowles,

    1. Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland 20910, USA
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  • John R. Kucklick,

    1. National Institute of Standards and Technology, Hollings Marine Laboratory, Charleston, South Carolina 29412, USA
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  • Margie M. Peden-Adams

    1. Marine Biomedicine and Environmental Sciences Center, Medical University of South Carolina, Charleston, South Carolina 29412, USA
    2. Molecular and Cell Biology Program, Medical University of South Carolina, Charleston, South Carolina 29425, USA
    3. Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina 29425, USA
    4. Mystic Aquarium and Institute for Exploration, Mystic, Connecticut 06355, USA
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Abstract

Cetaceans are federally protected species that are prone to accumulate complex mixtures of persistent organic pollutants (POPs), which individually may exert estrogenic or antiestrogenic effects. In the present study it was assessed whether contaminant mixtures harbored by cetaceans are estrogenic or antiestrogenic using a comparative approach. Interactions of antiestrogenic and estrogenic compounds were first investigated with the E-Screen assay using a mixture of four POPs (dichlorodiphenyldichloroethylene [4,4′-DDE], trans-nonachlor, and polychlorinated biphenyls [PCBs] 138 180) prevalent in cetacean blubber. Estrogenic/antiestrogenic activity was determined for the individual compounds and their binary, tertiary, and quaternary combinations. Significantly different responses were observed for the various POP mixtures, including enhanced estrogenic and antiestrogenic effects and antagonistic interactions. These results were then compared to the concentrations and estrogenic/antiestrogenic activity of contaminant mixtures isolated directly from the blubber of 15 bottlenose dolphins (Tursiops truncatus) collected from five U.S. Atlantic and Gulf of Mexico locations. The lowest observed effect concentrations (LOECs) determined for 4,4′-DDE (20 µmol/L), PCB 138 (20 µmol/L), PCB 180 (21 µmol/L), and trans-nonachlor (3 µmol/L) in the E-Screen were greater than estimated dolphin blood concentrations. Although estimated blood concentrations were below the LOECs, significant estrogenic activity was detected in diluted dolphin blubber from Cape May, NJ and Bermuda. Positive correlations between blubber estrogenicity and select POP concentrations (ΣDDTs, ΣPBDEs, ΣHCB, Σestrogenic PCBs, Σestrogenic POPs) were also observed. Collectively, these results suggest that select bottlenose dolphin populations may be exposed to contaminants that act in concert to exert estrogenic effects at biologically relevant concentrations. These observations do not necessarily provide direct evidence of endocrine disruption; however, they may indicate an environmental source of xenoestrogenic exposure warranting future research. Environ. Toxicol. Chem. 2010;29:2143–2153. © 2010 SETAC

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