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Anemia, Hypothyroidism and Immune Suppression Associated with Polychlorinated Biphenyl Exposure in Bottlenose Dolphins (Tursiops truncatus)



John Kucklick, Lori Schwacke, Eric Zolman, Brian C. Balmer, Sylvain De Guise, Clay George, Jennifer Hoguet, Steve Lamb, Milton Levin, J. L. Litz, W E. McFee, Ned Place, Forrest Townsend, Teresa Rowles, Randall Wells, Aleta Hohn


Background: Polychlorinated biphenyls (PCBs) and other legacy organohalogens are often monitored in marine mammals both to understand health risks for populations of these protected species and as an indication of marine food web contamination. Bottlenose dolphins, which maintain a high trophic position and have a relatively long lifespan, are sensitive indicators of PCB contamination and may provide insight into associated chronic health effects. Dolphins inhabiting estuaries near Brunswick, Georgia, USA are exposed to extremely high levels of a unique PCB mixture, Aroclor 1268, dominated by highly chlorinated octa- through deca-chlorobiphenyl congeners. Objectives: We assessed the health of dolphins inhabiting waters along the Georgia coast to examine potential associations between PCB exposure and health status. Methods: Health assessments were conducted on bottlenose dolphins from the Turtle/Brunswick River Estuary and a nearby estuarine research reserve. Dolphins were given a complete clinical evaluation and samples of blood and other tissues were collected for a suite of diagnostic tests. Results: We found a high prevalence of multiple disease conditions, including anemia and hypothyroidism; significant negative correlations were observed between blubber PCB concentration and thyroid hormones as well as functional immune indices. Conclusions: Detrimental health effects were observed even though the PCB mixture to which the dolphins were exposed was dominated by highly chlorinated, non-dioxin-like congeners. The PCB concentrations found in these coastal dolphins suggest that bioavailable PCBs remain in the marine food web where they pose a significant risk to marine wildlife and potentially coastal residents who regularly consume local seafood.
Proceedings of the Royal Society B – Biological Sciences


marine mammal, health, endocrine disruption, persistent organic pollutant


Kucklick, J. , Schwacke, L. , Zolman, E. , Balmer, B. , De Guise, S. , George, C. , Hoguet, J. , Lamb, S. , Levin, M. , Litz, J. , McFee, W. , Place, N. , Townsend, F. , Rowles, T. , Wells, R. and Hohn, A. (2011), Anemia, Hypothyroidism and Immune Suppression Associated with Polychlorinated Biphenyl Exposure in Bottlenose Dolphins (Tursiops truncatus), Proceedings of the Royal Society B – Biological Sciences, [online], (Accessed July 18, 2024)


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Created May 25, 2011, Updated March 4, 2022