Geologically distinct crude oils cause a common cardiotoxicity syndrome in developing zebrafish

Area of Science:

• Environmental Toxicology
• Marine Biology
• Ecotoxicology

Background:

• Crude oils contain polycyclic aromatic hydrocarbons (PAHs) known to cause cardiotoxicity in developing fish.
• Understanding variations in crude oil toxicity is crucial for assessing environmental impacts of spills.

Purpose of the Study:

• To compare cardiotoxic effects of two different crude oils (Iranian Heavy Crude Oil and Alaska North Slope Crude Oil) on zebrafish embryos.
• To investigate how weathering affects crude oil toxicity and the underlying mechanisms.

Main Methods:

• Zebrafish embryos were exposed to water-accommodated fractions and oiled gravel effluent from weathered and unweathered crude oils.
• Cardiotoxicity phenotypes and aryl hydrocarbon receptor (AHR) activation patterns were analyzed.

Main Results:

• Both crude oils induced similar cardiac defects, including impacts on ventricular contractility and chamber looping.
• Weathering altered tissue-specific AHR activation, with myocardial AHR activation observed when alkyl-PAHs predominated.
• Cardiotoxicity mechanisms appeared to shift from AHR-independent to multiple/synergistic pathways with increased weathering.

Conclusions:

• Crude oil cardiotoxicity in early fish development shows largely overlapping effects across different oil types.
• Weathering influences the mechanisms of crude oil toxicity, potentially involving AHR-dependent and independent pathways.
• Existing research on Alaska North Slope Crude Oil is broadly applicable to understanding impacts from other crude oil spills.