A reproductive toxicology study of phenanthrene in medaka (Oryzias latipes).

Environmental contaminants, such as polycyclic aromatic hydrocarbons (PAHs), can disrupt the endocrine system and affect reproductive function of humans and wildlife. In this study, we exposed Japanese medaka (Oryzias latipes) to water-borne or food-spiked phenanthrene, an ubiquitous PAH, and investigated the chronic effects of the chemical on medaka reproduction. The results showed that phenanthrene significantly prolonged the time to hatch for embryos. Other parameters such as fecundity and fertility, organ-somatic ratios, hepatic vitellogenin production, and the histology of testes and ovaries were not different between the control and phenanthrene-treated groups. This suggests that the time to hatch in embryos might be a more sensitive biomarker for environmental contaminants.