Date of Award
Master of Science
Traditional assessments of contaminated sites require the collection and analysis of field media. Specifically, sediment analysis is used to determine type of contaminant as well as total contaminant concentrations (TCC). Although TCC can be used to determine if a site is contaminated, it is unable to adequately predict exposure and bioaccumulation in organisms. Biota-sediment accumulation factors were originally introduced to calculate and predict expected exposure to organisms based on sediment TCC. As they have been shown to be unreliable with field sediments, their use is limited. Alternatively, Tenax has been examined as a tool for measuring exposure to hydrophobic organic contaminants, where the Tenax extractable concentration is related to the bioaccumulated organism concentration. Although this relationship has been demonstrated in multiple studies, few have actually related the data from multiple sites to develop a standard model of Tenax accumulation. This research had two specific goals: Develop a literature based model of Tenax accumulation of polychlorinated biphenyl congeners (PCBs) and test it's applicability to field collected sediments from the Ottawa River (OR, Toledo OH, Chapter 2) and verify the use of the model in a highly-disturbed, post-dredge system, as well as the use of Tenax as an indicator of changes in bioavailability after dredging (Chapter 3). The literature-based complete Tenax model (TM) provided a strong model for the prediction of bioaccumulation in Lumbriculus variegatus (r2=0.91). When compared to the pre-dredge data from the OR, 95% of the data were encompassed by the CTM. No bias of the model was observed across homologue groups. Subsequently, the model was used with sediments collected after remediation via dredging from the OR. In this study, the CTM encompassed 73% of the data. Although all sites along the river were considered disturbed by the dredging, resuspension, and drift of sediments, data from sites that were less disturbed were better described by the model (86% versus 64% of dredged data). Overall, the CTM is recommended for use in the prediction of exposure and accumulation of PCBs in field sediments.
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