Acute toxicity (daphnia)

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Term Acute toxicity (daphnia)
Definition The purpose of this test is to determine the median effective concentration for immobilization (EC50) of a substance to Daphnia in fresh water. It is desirable to have, as far as possible, information on the water solubility, vapour pressure, chemical stability , dissociation constants and biodegradability of the substance before starting the test.

Additional information (for instance structural formula, degree of purity, nature and percentage of significant impurities, presence and amount of additives, and n-octanol/water partition coefficient) should be taken into consideration in both the planning of the test and interpretation of the results.

A limit test may be performed at 100 mg per litre in order to demonstrate that the EC50 is greater than this concentration. The Daphnia are exposed to the test substance added to water at a range of concentrations for 48 hours.

If a shorter test is used, justification should be given in the test report.

Under otherwise identical test conditions, and an adequate range of test substance concentrations, different concentrations of a test substance exert different average degrees of effect on the swimming ability of Daphnia. Different concentrations result in different percentages of Daphnia being no longer capable of swimming at the end of the test. The concentrations causing zero or 100 % immobilization are derived directly from the test observations whereas the 48-hour EC50 is determined by calculation if possible.

References 1.
Additional Information