Date of Award

2017

Document Type

Open Access Thesis

Department

Environmental Health Sciences

Sub-Department

The Norman J. Arnold School of Public Health

First Advisor

Geoffrey I. Scott

Abstract

There are numerous cases of intersex condition in fish, specifically immature oocytes in testicular tissue, documented in recent literature. Typically, these cases identify a point source input of endocrine disrupting compounds impacting the fish, such as wastewater treatment effluent. Legacy contaminants such as polychlorinated biphenyls (PCBs) have been suggested as endocrine disruptors in fish species. The objective of this study was to assess endocrine disruption in wild largemouth bass (Micropterus salmoides) from exposure to PCBs at a Superfund site in South Carolina on Lake Hartwell (SV-107), where high levels of PCBs in sediment and fish tissue samples have been detected for many years. A less severely PCB-contaminated site on Lake Hartwell (SV-535) and a reference site upstream on Lake Keowee (SV-311) were also sampled. Endocrine disruption in fish was measured by analyzing plasma vitellogenin (VTG), intersex severity, and intersex prevalence. Measurable levels of plasma VTG, an egg yolk precursor protein, were detected in male fish from all sites. There were no cases of intersex observed in females collected for this study. Intersex in males manifested as testicular oocytes (TO). Histological analysis indicated that testicular oocytes were present in 23 of 33 (69%) of male largemouth bass sampled and was found in fish from all three sites. These data suggest there may be a significant association between PCB concentration in fish tissue and endocrine disruption in the form of VTG production, intersex severity, and intersex prevalence in male largemouth bass.

Rights

© 2017, Stephanie B. LaPlaca

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