Swimming Performance of Juvenile Florida Pompano after Sublethal Exposure to Ethylene Glycol and Methanol: Synergistic Effects

Abstract

Chemical additives for enhancing deepwater (>305-m) petrochemical production, such as ethylene glycol and methanol, are used to prevent the formation of gas hydrates in deepwater wells and pipelines and pose threats to marine faunas. Juvenile Florida pompano Trachinotus carolinus were used in controlled experiments to test the effects of 3.0% (volume per volume) ethylene glycol, 1.07% methanol, and a combination of the two chemicals on the swimming performance of individuals. We quantified the sublethal effects of contaminants by comparing differences in pre- and postexposure critical swimming speeds (U _crit) among treatment and control groups. In juvenile swimming performance tests, single exposure to ethylene glycol and to the combination of ethylene glycol and methanol significantly reduced mean U _crit by 13.4% and 41.1%, respectively. No detectable difference in U _crit was found for control groups or juveniles exposed solely to methanol. The sublethal effects of single exposures to ethylene glycol and methanol were increased synergistically more than threefold when juveniles were exposed to the contaminants in combination. The reduced ability to sustain high and prolonged performance levels could affect an individual's ability to avoid predators and feed effectively.