| I investigated the contributions of hydrophobicity, species differences, and spatial and temporal variation to individual variability in PCB concentrations using three species of cyprinids, bluntnose minnows (Pimephales notatus ), emerald shiners (Notropis atherinoides), and spottail shiners (Notropis hudsonius). I then investigated the influence of variation in chemical, physiological, and ecological characteristics on trophic magnification factors (TMFs), a food-web bioaccumulation metric commonly used by regulators. PCB concentrations are influenced most notably by hydrophobicity which explains 14% of the variability. When drivers are examined on a KOW-specific basis physiological and ecological factors have differing importance, for instance species differences account for twice as much variation for PCBs with log KOW > 6.0. Finally, I used a food-web biomagnification model to investigate the sensitivity of TMFs to chemical and ecological perturbations demonstrating the importance of spatial and temporal variation in contaminant concentrations and the need to incorporate top predator foraging ranges into sampling strategies. |
