The effect of some organic solvents on the behavior and antioxidant enzyme activity of Daphnia magna

This study was conducted to demonstrate the potential toxic effects of some organic solvents (Toluene, Chloroform, n-Hexane, and Phenol) on Daphnia magna, both physiologically and biochemically. In the study, D. magna was exposed to doses of the 4 organic solvents at 1/50, 1/100, and 1/200 of the previously reported lethal doses found in the literature for a duration of 14 days. On the 3rd, 7th, and 14th days of exposure, the heart rate, thoracic, and abdominal cavity activities of Daphnias were examined. Additionally, malondialdehyde (MDA), catalase (CAT), glutathione (GSH), and glutathione S-transferase (GST) activities were determined. Physiological activities such as heart rate, thoracic, and abdominal cavity activities started to decrease on the 3rd day of exposure in all solvent applications, and especially the heart rate came to a standstill at the end of the exposure period. Significant differences were found for all three activities. Time-dependent increases were observed in MDA, CAT, and GST activities in all experimental groups where each solvent application was made, and these increases were statistically significant compared to the control group (P<0.05). However, a significant decrease in GSH levels was observed over time in all solvent groups compared to the control group (P<0.05). As a result, it has been clearly demonstrated that these solvents, which can be discharged into surface waters for various reasons, have a toxic effect on aquatic organisms. Therefore, it is essential to take necessary measures to prevent the release of these and similar pollutants into our waters.