OECD 202, Regulation (EG) Nr. 440/2008 C.2, DIN EN ISO 6341, DIN 38412-L30
Daphnids are small crustaceans that belong to the zooplankton and play an important role as filtering organisms in the aquatic ecosystems of stagnant waters. The purpose of this test is to determine the immobilisation of the Cladoceran Daphnia magna by test substances or wastewater.
The daphnids are exposed to the test substance in a defined test medium. After 24 or 48 h, the mobility of the daphnids is examined. The dose-effect relationship is calculated by a statistical software. From this the 50% effect concentration (EC50) related to the mobility of the daphnids can be calculated as final result.
Test substance properties
Dependent on the characteristic of the test substance the design of the test will be adapted: static test design without renewal of the test solution for soluble substances and semistatic test design with renewal of the test solution after 24 h for unstable or adsorbing substances.
For testing wastewaters, the daphnia toxicity test is applied in a more simplified screening version with two parallel test vessels each containing 5 daphnids per test concentration. Test duration is 24 h. The Lowest Ineffective Dilution, for which at least 90% of the daphnids are mobile, is given as test result (=LIDD-value). Hereby, the LID corresponds to the dilution factor or the reciprocal value of the volume proportion of the wastewater (No. 402 Wastewater Ordinance and DIN 38412-L30).