ALGAL GROWTH INHIBITION TEST/ FeMn slag (Ferro-manganese slag)/ OECD 201/ GLP
Introduction. A study was performed to assess the effect of the test item on the growth of the green algae Desmodesmus subspicatus. The method followed that described in the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test", referenced as Method C3 of Commission Regulation (EC) 440/2008.
Results. Exposure of Desmodesmus subspicatus to the test item gave the following results:
| Response variable |
EL*50 (mg/l Loading Rate WAF) |
95% Confidence Limits (mg/l Loading Rate WAF) |
No Observed Effect Loading Rate (NOEL) (mg/l) |
Lowest Observed Effect Loading Rate (LOEL) (mg/l) |
| Growth rate | 90 | ** | 10 | 32 |
| Yield | 39 | 34 - 46 | 10 | 32 |
The test item contains manganese. The test concentrations were monitored by analysis of the test samples for manganese only.
*EL = Effective Loading Rate
**It was not possible to calculate 95% confidence limits for the ErL50 value as the data generated did not fit the models available for the calculation of confidence limits.
Analysis of the test preparations at 0 and 72 hours showed measured concentrations of manganese to be less than the limit of quantitation (LOQ) of the analytical method employed. This does not infer that no test item was in solution, merely that the test item(s) which was present was at a concentration below the LOQ.
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