Effect of toluene on fathead minnow (Pimephales promelas Rafinesque) development

The environmental levels of aromatic hydrocarbons present in freshwater systems have been poorly characterized. This study examines the effect of toluene, a major water-soluble component of petroleum fuels on teleost development under controlled conditions. The fathead minnowPimephales promelas Rafinesque, was chosen as a model teleost for this study. Live embryos as well as serial sections of paraffin-embedded embryos were examined to determine effects of the toxicant. The toluene concentrations utilized ranged from 30 to 45 mg/L. Abnormalities noted under these conditions included distorted embryonic axis, abnormal heart and circulatory system development, hydration and swelling of the pericardial coelom, hemorrhaging, an overall stunted appearance, microphthalmia, and a unique migration of the ventrally located yolk syncytial layer and its associated nuclei.