Franz Giersdorf

• Background: Neurodegenerative diseases are on the rise. A possible link between the exposure and residue of neuroactive compounds to the environment and humans was found in recent years. At the present day the effects of chemical mixtures are a field of great concern. However aquatic communities and organism seem even more vulnerable to adverse effects of toxic mixtures. Zebrafish was selected as suitable in vivo model to investigate these concerns. The possible effects of nine selected compounds and four binary mixtures were assessed by an evaluation of movement change in D. rerio embryos at early life stages. Results: The investigation has shown various changes in the behavior of D. rerio embryos for eight of nine tested compounds and their mixtures, respectively. The STC (spontaneous tail coiling)-method revealed changes in hyper- and hypoactivity in zebrafish. Conclusions: This report demonstrates the advances of investigating sublethal behavior-related endpoints linked to observed effects regarding to a specific mode of action or to a certain group of compounds, respectively. Furthermore, the STC-method proved to be a promising tool to detect, evaluate and investigate combined effects in binary mixtures. Keywords: Danio rerio embryos, behavior, mixtures, neurotoxicity, sublethal endpoints, STC-method, movement change