Long-term exposure to polycyclic musk tonalide- A potential threat to juvenile zebrafish (Danio rerio)?

Polycyclic musk compounds are commonly used in personal care products to replace expensive natural fragrances. Due to their huge consumption, they have become a part of the aquatic environment. In the present a two-month exposure effect of tonalide on juvenile zebrafish (Danio rerio) was investigated. We deter-mined the vitellogenin concentration to define the potential endocrine-disrupting effect of tonalide and also ana-selected indices to evaluate the induction of oxidative stress. The environmentally relevant concentration tonalide (i.e., 500 ng/l) caused a significant decrease in the catalase activity (P < 0.05) and a significant increase 0.05) in the lipid peroxidation. An increasing lipid peroxidation was also recorded for the highest concentra-group tested (i.e., 50 000 ng/l). On the other hand, no significant changes were recorded in vitellogenin in all exposed groups. Thus, based on these results, we have not demonstrated the endocrine-disrupting activity tonalide in zebrafish. The results of the oxidative stress indices showed a significant impairment of the anti-oxidant defence after the two-month tonalide exposure, which could indicate part of the adaptive response tonalide toxicity.