Cardiotoxicity and interspecies sensitivity of early life stage fish to polycyclic aromatic compounds
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Date
2025
Authors
McKenzie, Kristin C. R.
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences
Abstract
Polycyclic aromatic compounds (PACs) are a broad class of organic contaminants that are present in all types of hydrocarbon fuels and produced from the incomplete combustion of organic matter. During early development, PAC exposure induces sublethal and lethal toxicity in fish. Predictive tools such, as the target lipid model (TLM), have been developed to estimate these impacts. Although cardiotoxicity is a well-established outcome of early life stage crude oil and PAC exposure, few studies have compared cardiotoxicity endpoints across freshwater fish species, and applications of cardiotoxicity endpoints within a TLM framework remain limited. Therefore, the aim of this study was to compare lethal and cardiotoxicity endpoints of larval walleye (Sander vitreus), fathead minnow (Pimephales promelas), and rainbow trout (Oncorhynchus mykiss) following exposures to naphthalene, dibenzothiophene and benz(a)anthracene. Larvae from each species were exposed using a passive-dosing system to five serial concentrations of each PAC, with exposures initiated within 24 h post-hatch and terminated at seven days post-hatch. The TLM framework was able to effectively characterize lethality, bradycardia and ventricle to atrium length ratio (walleye only), enabling a critical target lipid body burden (CTLBB) for each endpoint and species. Although walleye exhibited significantly lower sensitivity to acute lethality relative to the other species, no significant differences between species were observed for bradycardia endpoints. Despite their high survival, walleye exhibited significant reductions in ventricle length and diminished cardiac function following exposure to PACs. This study is the first to successfully apply cardiotoxicity endpoints in fish to a TLM and the first to produce CTLBB data for walleye. Results from this study further support the integration of cardiac endpoints into TLM-based approaches for improving the prediction of sublethal impacts from oil spills.
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Keywords
polycyclic aromatic compounds , cardiotoxicity , passive dosing , fish , target lipid model