Date of Award

8-2007

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Environmental Toxicology

Advisor

van den Hurk, Peter

Committee Member

Rice , Charles D.

Committee Member

Klaine , Stephen J.

Abstract

Freshwater species in South Carolina have been declining for many years. However, the threats that these organisms face from point and non-point source pollution are largely unknown. The South Carolina Department of Natural Resources (SCDNR) began a five year survey of the wadeable streams of South Carolina in May 2006. One of the purposes of this study was to use molecular biomarkers of contaminant exposure to fully assess the health of fish in South Carolina's freshwater streams. During the first year of the study, sunfish (Lepomis sp.) were sampled from May through September 2006 at randomly selected sites in three ecobasins in South Carolina (the Saluda Sandhills, the Savannah Sandhills, and the Pee Dee Atlantic Southern Loam Plains). Somatic indices, including hepatosomatic index (HSI), spleen somatic index (SSI), gonadosomatic index (GSI), and Fulton's condition factor (K) were measured to determine the overall bodily condition of the fish. Cytochrome p4501A induction (as measured by the EROD assay) and bile fluorescence were measured to estimate exposure to polycyclic aromatic hydrocarbons (PAHs). Glutathione-s-transferase (GST) activity was measured to estimate oxidative stress. Additionally, measurements of land use and fish assemblage structure were used to determine relationships between land use and biomarker measurements. Results indicate that the HSI, SSI, and GSI were influenced by several factors, including sex, season, and the presence of parasitic infection. Though both EROD and GST were not induced beyond basal levels for the fish sampled, bile fluorescence was significantly elevated at fish from specific sites within the Saluda Sandhills and Pee Dee Atlantic Southern Loam Plains, indicating possible transient exposure to and metabolism of PAHs at these sites. Fish from these ecobasins also had higher EROD activities, bile fluorescence, and HSIs than the Savannah Sandhills, again suggesting possible exposure to higher levels of PAHs than the Savannah Sandhills. Additionally, bile fluorescence and HSI were significantly correlated with the percentage of impervious surface cover within the watershed area at sites, demonstrating a possible link between PAH exposure and land use. This study provided a first estimate of the health of fish in specific ecobasins of South Carolina as part of a five year survey of the wadeable streams of South Carolina.

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