Meeting Abstract
The use of chemical dispersants to remediate crude oil spills is common, especially in estuarine areas, and its effectiveness is dependent upon many properties of water, such as salinity. Crude oil is composed of polycyclic aromatic hydrocarbons (PAHs), which are extremely toxic to aquatic organisms. Dispersants facilitate the breakup of oil molecules, dispersing them through the water column, which leads to the uptake of PAHs through gills of fish. Not only can PAH exposure lead to osmoregulatory imbalances, but it activates the stress response system and can cause structural damage to gill epithelia. To observe these effects, adult bluegill,Lepomis macrochirus, were exposed to treatments of crude oil, chemical dispersant, and chemically dispersed oil in both freshwater and 1.5% salinity for 48 hours. Blood parameters were tested and gill morphology was analyzed both qualitatively and quantitatively. There were profound qualitative proliferative and degenerative changes in gill epithelia for all treatment groups, as well as differences in lamellar length and width. Proliferative changes included hypertrophy and hyperplasia of epithelial cells, and degenerative changes observed were epithelial cell lifting and rupture, lamellar fusion, and necrosis of filamentary epithelium. Significant differences were observed in fish exposed to dispersed oil in freshwater for glucose relative to the control, and both hematocrit and hemoglobin were higher in fish in saltwater compared to the respective freshwater groups. These results support current similar research in fish toxicology and indicate that anthropogenic pollution, and ways in which it is remediated, affects various physiological and anatomical parameters of aquatic organisms.
