M8 AM Persistent Organic Pollutants
Monday, 14 November 2005: 8:00 AM - 11:40 AM in 337-338

(MAR-1117-845112) Bioaccumulation and biomagnification of POPs by bottlenose dolphins in coastal Georgia (USA).

Pulster, Erin¹, Maruya, Keith², ¹ Skidaway Institute of Oceanography, Savannah, GA, USA² Southern California Coastal Water Research Project, Westminster, CA, USA

ABSTRACT- In coastal ecosystems, top aquatic predators such as marine mammals are exposed to persistent organochlorine pollutants (POPs) via contaminated fish that serve as part or all of their diet. Inshore populations of bottlenose dolphins (Tursiops truncatus) in particular are thought to be at risk because they consume fish as their preferred prey, have limited POP biotransformation capacity, and exhibit long-term fidelity to specific tidal estuaries. The objective of this research was to generate and validate a predictive POP biomagnification model for T. truncatus in southeastern U.S. estuaries, including the heavily contaminated Turtle/Brunswick River (TBR) estuary in coastal Georgia (USA). Mean total PCB and toxaphene (TOX) concentrations were up to two orders of magnitude greater in TBR fish species preferred by inshore Tursiops (42 and 49 mg/kg lipid, respectively) than in other regional estuaries. Prey- and estuary-specific modeling suggests that inshore TBR dolphins would accumulate POPs (approx. 60 mg/kg lipid total PCB; approx. 20 mg/kg lipid total TOX) to levels that exceed thresholds associated with deleterious effects. Order of magnitude agreement between predicted and recently measured POP concentrations in T. truncatus blubber from strandings (n=6) and dart biopsy samples (n=7) was achieved, with better concordance for PCBs than toxaphene. This on-going study indicates that contaminated prey (fish in this case) serve as important vectors as well as predictive modeling elements for biomagnification of POPs in coastal aquatic systems.

Key words: biomagnification, dolphin, polychlorinated biphenyls, toxaphene