Factors Influencing Bioaccumulation of Polychlorinated Biphenyls in Six Fish Species in Logan Martin Reservoir, Alabama

Abstract

The objective of this project was to evaluate the biological and environmental factors that influenced the bioaccumulation of polychlorinated biphenyls (PCB) in the consumptive portions of fish. I investigated the relationships of seven different factors that might potentially impact the uptake of PCBs in fillets in largemouth bass Micropterus salmoides, spotted bass Micropterus punctulatus, striped bass Morone saxatilus, black crappie Pomoxis nigromaculatus, and freshwater drum Aplodinotus grunniens from Logan Martin Reservoir, Alabama (N=1022). These factors include temporal trends, spatial trends (distance at capture), lipid content, total length, relative weight, age, and gender. Regression techniques were employed to identify those variables having the most influence on PCB concentrations in fish fillets of each species. Regression modeling was evaluated at two contrasting conditions: relatively high (1996) and low concentrations (2001-2002). In these models, lipid content and distance at capture appeared to be the dominant predictors of PCBs in all six species. Total length, relative weight, and gender (2001-2002 only) also explained some additional variability in a few species. In addition, PCB concentrations were not related to fish age for any species in the relatively low concentration period (2001-2002). Multiple regression modeling for PCB trends concluded that the natural log transformation of PCB concentrations (lnPCB) declined significantly (p<0.05) from 1996 to 2002 in all six species when evaluated for differences between the three sampling years (1996, 2001, and 2002). In these final models, all six species were positively related to lipid content and every species except striped bass were negatively related to distance at capture. However, the influence of each of these variables on PCB concentrations was species specific and highly variable. ANOVA testing along with Dunnett’s C post hoc tests showed PCB concentrations in striped bass and spotted bass were significantly greater than the other species evaluated. Species specific regression models that include these bioaccumulative factors should be integrated into PCB monitoring plans associated with fish consumption advisories.