Cardiovascular Toxicity in Daphnia magna: Heart Rate Analysis Under Exposure to Crystal Violet, Ethanol, and Formaldehyde

Water fleas have become valuable model organisms for ecotoxicity studies due to their ease of cultivation, transparent bodies, and high sensitivity to chemical pollutants. In this study, heart rates in Daphnia magna were examined to assess basic behavioral and physiological characteristics under exposure to known toxic chemicals. Crystal violet, ethanol, and formaldehyde selected for their distinct chemical properties and documented toxicity were utilized as toxic solutions. A slow-motion, video-based method was implemented to evaluate cardiovascular performance by monitoring heart rates in water fleas. Data for important parameters like heart rates, body reactions, and heart contraction were extracted from video recordings. It was found that crystal violet increased the heart rates of Daphnia magna (489±14.19) more than ethanol (450±40.67) and formaldehyde (445±48.21). Compared to the control group, formaldehyde caused a 28.51% increase in the heart rates of daphnids, while exposure to ethanol (30.54%) and crystal violet (35.89%) resulted in a lower increase. The response of water fleas to each of the three chemicals studied was determined as a statistically significant and noticeable increase in heart rate.