An accurate and sensitive method for neurotoxicity assessment of emerging contaminants in zebrafish

The rapid increase in emerging contaminants driven by industrialization poses significant threats to both ecosystems and neurodevelopmental health, underscoring the urgent need for sensitive and accurate screening platforms for developmental neurotoxic compounds. Here, we developed a zebrafish-based multi-indicator assessment system to overcome the limitations of conventional behavioral assays. The morphologies of the head, actions of microglial cells, numbers of motor neurons, changes in neuronal activity and behavioral mobility of zebrafish larvae are examined and set as assessment criteria. When validated with 12 known neurotoxicants, our approach significantly improved detection rates compared to previous behavioral screening methods. Specifically, 8 compounds (66.67 %) affected either interocular distance or midbrain area. 10 neurotoxic pollutants (83.33 %) were identified by observing the actions of microglia, while 9 compounds (75 %) showed effects on the patterns of neuronal cell activity and 7 compounds (58.33 %) were identified by the number of motor neurons. Furthermore, a scoring system was established by integrating these indicators, enabling simultaneous hazard identification and risk prioritization. This multi-dimensional assessment approach substantially minimizes the risk of omissions associated with relying on a single indicator. Overall, the sensitivity and accuracy of this method provide an efficient tool for screening and evaluating potential developmental neurotoxic pollutants, thereby supporting the management and risk mitigation of emerging contaminants.