Daphnia sp. Acute Immobilization Test (OECD TG 202)
The Daphnia sp. Acute Immobilization Test according to OECD TG 202 is used to evaluate the short-term toxic effects of substances on aquatic invertebrates. Daphnia, commonly known as water fleas, are highly sensitive organisms and serve as key indicators for assessing environmental hazards in freshwater ecosystems.
In this test, juvenile Daphnia (typically less than 24 hours old) are exposed to a series of concentrations of the test substance under controlled laboratory conditions for a period of 24 to 48 hours. The primary endpoint is immobilization, defined as the inability of the organisms to swim within a specified period after gentle agitation.
The test aims to establish concentration–response relationships and to determine the median effective concentration (EC₅₀), which represents the concentration causing immobilization in 50% of the test organisms.
Results from this study are essential for environmental risk assessment and regulatory evaluation, providing insight into the potential acute toxicity of chemicals to aquatic invertebrates.
