Estimating the risk of polychlorinated biphenyls (PCBs) in aquatic systems requires evaluation of exposure, usually based on exhaustive chemical extraction of sediment and potentially exposed organisms and an assessment of toxicity. Remediation can then focus on areas where the exposure leads to the highest risk. Although effective, an approach that estimates exposure, which accounts for bioavailabilty, bioaccumulation, trophic transfer potential, and transport of materials within and out of the waterway, should serve as a more comprehensive environmental assessment. The current study examined exposure of PCBs in several different trophic levels within the Campus Lake ecosystem, Carbondale, Illinois. The source of contamination and the distribution of PCBs among ecosystem components demonstrated contamination within the aquatic portion of Campus Lake and transport out of the aquatic environment to the riparian area. Several media were collected including sediment, emergent insects, spiders, and three species of fish. Sediment extractions demonstrated that PCBs were localized to one small cove and this area served as the source for transfer of PCBs to both aquatic and terrestrial organisms. Single-point 24-h Tenax extractions formed the basis for evaluating the bioavailable component of the sediment-associated PCBs with strong correlations to laboratory-based bioaccumulation assays for oligochaetes and chironomid larvae. Stable isotope data suggested that the source of carbon to the food web was relatively constant. Food web samples of emerging insects, fish, and spiders revealed that the PCBs in Campus Lake were bioavailable and the pattern of the PCB signature among food web components followed typical food web processes. The PCB congener pattern was consistent between emergent midges and spiders demonstrating the transfer of PCBs from aquatic to terrestrial species. The PCB concentrations detected in emerging insects from the contaminated area were on average 25 times greater than those detected in emerging insects from reference sites outside the area of greatest sediment contamination. High PCB concentrations found in several species of fish suggested that despite the localized sediment contamination, fish throughout the lake were exposed. These levels also exceeded the fish consumption advisory criteria. The PCB pattern comparisons suggested that the contaminated sediment was the source of exposure throughout the food web. This approach identified the scope of exposure to organisms, demonstrated bioavailability, and provided a basis for future PCB remediation and subsequent monitoring of Campus Lake. In comparison to studies focused solely on limited sampling of fish for consumption advisory purposes, this approach demonstrated the importance of more comprehensive studies to examine the range of ecosystem exposure even from very limited contamination sources.

Fish consumption advisories are increasingly being issued by state and municipal governments with concerns about pollution in local waterways. These advisories are developed to inform the public about the potential dangers of consuming excessive amounts of locally caught fish. They are not enforceable limits, however, and are only guidelines and suggestions on what are considered safe meal sizes, safe meal frequencies, and species fit for consumption. As a result, few efforts are made to determine how well these advisories are being followed. In order to determine the efficacy of such urban advisories, anglers are interviewed in Washington, DC on the Potomac and Anacostia Rivers. Anglers are asked a number of questions pertaining to their fishing and consumption habits, advisory knowledge, and risk perceptions. The results suggest that several improvements can be made to better implement advisory efforts. Most importantly, minority anglers—particularly African-Americans—appear to be receiving the message in advisories, but are failing to comply with advisory recommendations. Cultural beliefs and influences, as well as information dissemination inadequacies, are cited as possible reasons for this failure. Lastly, strategies are presented that health and fisheries planners can use to better understand angler risk perception and better educate anglers about the risks of ignoring advisory recommendations. / Master of Urban and Regional Planning

Increasing awareness about the presence and ecological ramifications of toxic, persistent and bioaccumulative contaminants within the Great Lakes system spurred the implementation of numerous bans and emissions restrictions over the past few decades. Due to their high trophic status in food webs and the critical link they serve with human consumers, fish species have historically been monitored to assess the relative success of such remedial efforts within the region and to simultaneously ascertain the current risks posed to local humans. Using Bayesian dynamic linear modelling, this project first aimed to evaluate temporal trends of various organochlorine contaminants within Lake Erie fish communities, the results of which generally indicated decreasing trends through time. The second half of this study used a similar Bayesian approach to propose a framework for updating fish consumption advisories, with specific attention paid to the acknowledgment of uncertainty and natural variability when producing such consumption guidelines.

Increasing awareness about the presence and ecological ramifications of toxic, persistent and bioaccumulative contaminants within the Great Lakes system spurred the implementation of numerous bans and emissions restrictions over the past few decades. Due to their high trophic status in food webs and the critical link they serve with human consumers, fish species have historically been monitored to assess the relative success of such remedial efforts within the region and to simultaneously ascertain the current risks posed to local humans. Using Bayesian dynamic linear modelling, this project first aimed to evaluate temporal trends of various organochlorine contaminants within Lake Erie fish communities, the results of which generally indicated decreasing trends through time. The second half of this study used a similar Bayesian approach to propose a framework for updating fish consumption advisories, with specific attention paid to the acknowledgment of uncertainty and natural variability when producing such consumption guidelines.