DAPHNID, CERIODAPHNIA DUBIA SURVIVAL AND REPRODUCTION TEST/ MnO2 (Manganese dioxide)/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 8-Day EC50 (immobilisation) value based on the nominal test concentrations, for the parental Ceriodaphnia generation (P1) was estimated to be greater than 100% v/v saturated solution.
The 8-Day EC50 (reproduction) value based on the nominal test concentrations was calculated to be 32% v/v saturated solution with 95% confidence limits of 20 - 50% v/v saturated solution.
The "Lowest Observed Effect Concentration" was considered to be 32% v/v saturated solution on the basis that at this test concentration produced significantly fewer live young per adult (P<0.05) than the control.
The "No Observed Effect Concentration" was considered to be 10% v/v saturated solution 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 10% v/v saturated solution test group in terms of numbers of live young produced per adult by Day 8.
The test item contains a theoretical manganese content of 63% w/w. The test samples were analysed for manganese only. Analysis of the test preparations on Days 0, 2, 5, 7 and 8 showed measured concentrations of manganese to be less than the limit of quantitation (LOQ) of the analytical method (assessed as 0.050 mg manganese/l) with the exception of the 32% and 100% v/v saturated solution on Days 0 (fresh media) and 2 (old media). Analysis of these samples showed measured concentrations as test item of 0.233 and 0.810 on Day 0 and 0.138 and 0.666 mg/l on Day 2.
Given that the majority of the analyses were less than the LOQ, it was considered justifiable to base the results on nominal test concentrations only.
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