DAPHNID, CERIODAPHNIA DUBIA SURVIVAL AND REPRODUCTION TEST/ MnO (Manganese Oxide)/OECD 211/ GLP
Introduction. A study was performed to assess the effect of the test item on the survival and reproduction of Ceriodaphnia dubia over an 8-Day period. The method followed that described in the OECD Guidelines for Testing of Chemicals No 211 (1998) "Daphnia magna, Reproduction Test", US EPA Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms (Method 1002.0) and OPPTS Ecological Effects Test Guideline, Daphnid Chronic Toxicity Test OPPTS 850.1300.
Results. The test item contained a theoretical manganese content of 77% w/w. The test samples were analysed for manganese only. Analysis of the fresh test preparations on Days 0, 2, 5 and 7 showed measured concentrations to range from 0.142 to 7.81 mg/l as test item. Analysis of the old media on Days 2, 5, 7 and 8 showed measured concentrations to range from 0.109 to 7.68 mg/l as test item. The measured concentration of the saturated solution, and hence the prepared dilutions, was observed to increase at each media renewal over the period of the test. A review of the data did not reveal a reason for this but may have been the result of slight changes due to media differences on a day to day basis.
Given that no decline in measured concentration was observed over each media renewal period, the results are based on the mean measured test concentrations as test item only. These were calculated to be 0.40, 1.3 and 4.1 mg/l.
The 8-Day EC50 (immobilisation) value based on the mean measured test concentrations as test item, for the parental Ceriodaphnia generation (P1), was estimated to be 4.1 mg/l.
The 8-Day EC50 (reproduction) value based on the mean measured test concentrations as test item was calculated to be 2.5 mg/l with 95% confidence limits of 2.2 - 2.8 mg/l.
The "Lowest Observed Effect Concentration" was considered to be 4.1 mg/l as test item on the basis that at this test concentration no live young were produced during the test.
The "No Observed Effect Concentration" was considered to be 1.3 mg/l as test item on the basis that at this test concentration there were no significant mortalities (immobilisation) observed in the parental generation (P1) and that there were no significant differences (P≥0.05) between the control and the 1.3 mg/l test group in terms of numbers of live young produced per adult by Day 8.
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