Multigeneration Effects of Chronic Exposure to Polycyclic Aromatic Hydrocarbons in Gulf Killifish (Fundulus grandis)

Abstract

The goal of this study was to examine potential adaptation within two generations of Gulf killifish exposed to polycyclic aromatic hydrocarbons (PAH) while also investigating the use of mucus as an effective and non-lethal alternative to determine concentrations of 11-ketotestosterone (11-KT) and vitellogenin (VTG) of F. grandis. Multiple biomarkers were used to assess adaptation within these fish, such as lysozyme (enzyme critical in innate immunity), and 11-ketotestosterone and vitellogenin (endocrine hormones often affected by PAHs). Mucal concentrations of 11-KT and VTG were determined and evaluated for effectiveness through comparative assays with blood plasma. This method was then applied to evaluate potential endocrine disruptions in F. grandis undergoing chronic exposure to a water accommodated fraction (WAF) of crude oil. Both 11-KT and VTG showed significant positive relationships between their respective concentrations in the plasma and mucus. Four populations of F. grandis with different exposure histories were exposed to WAF for 60 days, and followed 40 additional days after WAF treatments. Concentrations of 11-KT in mucus decreased throughout the 40 day WAF exposure period when compared to responses within control treatment males. Exposure history of the populations also had a significant effect on observed 11-KT concentrations in mucus; exposed Gangs Bayou males (reference site) had a decrease in 11-KT concentrations, while concentrations of 11-KT of exposed males from Vince Bayou (superfund site) increased. Exposed females showed near null concentrations of mucosal VTG when exposed to WAF regardless of exposure history while control groups did not exhibit deceases in mucus VTG concentrations. The second portion of this thesis details the exposures of two successive generations of Gulf killifish first to WAF and the second to naphthalene. Sperm motility and oocyte cell wall thickness was significantly lower in adults exposed to WAF, while egg viability and survival activity index were not. For the resulting progeny, lysozyme assessed within the surface mucus of Gulf killifish with naphthalene exposure significantly decreasing the relative concentration of lysozyme regardless of parental history. Changes in concentrations of lysozyme were also significant with the linear relationship of time, treatment and parental history with individuals from exposed parents showing overall higher concentrations than individuals from control parents. EROD induction was significantly higher in fish exposed to naphthalene regardless of parental history. Results show potential alteration to PAH metabolism and immunology within two generations in Gulf killifish.