MP12 Organic, Metallic, Organometallic Pollutants
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(LIE-1117-834714) Seasonal dynamics in bioaccumulation of PCBs by Chesapeake Bay striped bass.

Liebert, D¹, Baker, J¹, ¹ University of Maryland Chesapeake Biological Laboratory, Solomons, MD, USA

ABSTRACT- Striped bass from Chesapeake Bay were collected in spring and fall from 1999 to 2003 and analyzed for lipid content and polychlorinated biphenyls (PCBs). These fish showed a strong seasonal pattern of lipid and PCB concentrations with maxima of both in spring and minima of both in fall. As well, a seasonal difference in relative abundance of more chlorinated (heavy) versus less chlorinated (light) PCB congeners was observed. In spring, striped bass PCBs were dominated by lighter, more labile PCBs while PCBs in striped bass collected in fall were dominated by heavier more lipophilic congeners. To investigate a possible cause for our observations, we used a bioenergetic model for Chesapeake Bay striped bass and field measurements to generate lipid, consumption, and ventilation inputs for a toxicokinetic bioaccumulation model. This model demonstrated that seasonality of energetic status and respiration rates can account for the observed seasonal differences in PCB congeners. During summer and fall months when temperatures are high, respiration and ventilation rates are at a maximum and lipid content is at a minimum; these conditions allow for a rapid efflux of lighter, more labile PCB congeners, while heavier congeners remain bound in tissues. This model also suggests that the seasonal efflux of lighter PCB congeners is responsible for deceased total PCBs.

Key words: PCBs, striped bass, bioaccumulation, Chesapeake Bay