A Comparison of the Water Flea Static Non-Renewal Culture and Water Flea Continuous Culture Methods Using Continuous Culture Apparatus

The ecotoxicity value of unknown harmful substances contained in effluent was calculated by determining the health status of Daphnia magna (water fleas) through a standard reference toxicity test (ES 04705.1b). For this test, the Daphnia magna was cultured with static non-renewal culture and the Daphnia magna neonate was separated, which was time-consuming. This problem was solved by developing a continuous water flea culture apparatus and a continuous culture method. Standard reference toxicity tests were performed to confirm the health status of static non-renewal cultured Daphnia magna and continuous cultured Daphnia magna. We found that the average test value (EC50) for neonate separated from static non-renewal cultured Daphnia magna was 1.020 mg/L. Additionally, the average test value (EC50) for neonate separated in natural flow from continuous cultured Daphnia magna was 0.992 mg/L. It was confirmed that the EC50 values for potassium dichromate were in the satisfactory range of 0.9 to 2.1 mg/L, so it was valid for ES 04705.1b and ISO 6341:2012. In conclusion, there is a high chance for saving time and effort for toxicity evaluation when the continuous culture apparatus is used.