CEST2025

The armed conflict in Ukraine has had a severe impact on aquatic ecosystems, with military actions leading to contamination and habitat destruction. In response to this, six water samples were collected from bodies of water across four regions - Kyiv, Chernihiv, Kharkiv, and Odessa - all of which have been impacted by military operations. This study evaluates the effects of these water samples on the early development of Danio rerio embryos and larvae. Tail bursting activity of embryos at 24 hours post-fertilization (hpf) remained consistent across all samples, indicating no immediate neurodevelopmental impact. Heart rate (HR) measurements at 48 hpf showed a significant effect of water exposure; however, HR values did not significantly differ from the control group (p > 0.05). No significant differences in HR were observed at 96 hpf. However, a significant difference in hatching rates was observed among the water samples at 72 hpf (p < 0.05). Hatching rates (at 96 hpf) were similar across all groups, showing no significant differences between the treatment and control groups (p > 0.05). These findings suggest that exposure to specific water samples from conflict zones may transiently disrupt cardiac function and delay hatching in D. rerio, emphasizing the necessity for further research into the long-term implications on fish behavior and survival. Acknowledgement This work was funded by NATO Science for Peace and Security Programme “Creating a Strategy for Assessing and Restoring War-affected Aquatic Ecosystem” (Project No. G6085).