Freshwater Insect Mediated Transfer Of Polychorinated Biphenyls To Riparian Consumers

Abstract

Arnold Air Force Base has a legacy of polychlorinated biphenyl contamination (PCB) in nearby streams and a commitment to monitoring its influence on people and wildlife. Assessment of potential human PCB exposure from fish has consistently established that the majority of fish fillets are below concern for at-risk groups for PCB exposure. However, these levels of risk are not translatable to ecosystems, because the majority of PCBs are dissolved in fats and most animals consume food items whole or do not avoid eating adipose tissue. Grey bats seasonally consume emergent freshwater insects from Woods Reservoir and contaminated streams, which creates risk for PCB exposure and subsequent associated toxicological issues with combatting disease and reduced reproductive output. A previous study has documented as having more than a magnitude higher PCB concentration than those of other areas of Tennessee and Kentucky, which may be due to historical contamination. We will be using estimations of emergence to assess the export of insect biomass from streams and spiders to assess trophic transfer of PCBs to riparian predators. Long-jawed orb-weaving spiders provide insight into PCB biomagnification in bats, as both species have similar aquatic food sources. By assessing the amount of aquatic insects are consumed by the bats, a spider-based PCB risk assessment can be created for local grey bats. We believe this study can help inform bat management and PCB influence on freshwater and terrestrial ecosystems at Arnold Air Force Base.