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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

An algal growth inhibition study was performed with soda-ash flux calcined in accordance with OECD guideline 201. Exposure of Desmodesmus subspicatus to the test item gave EC50 values of greater than 100% v/v saturated solution 

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Additional information

The key study (Vryenhoef 2010) was performed according to GLP and OECD guideline 201. Pre-study solubility work conducted indicated that it was not possible to obtain a testable solution of the test item using traditional methods of preparation e.g. ultrasonication and high shear mixing. Given the insoluble nature of the test item and also its high purity value it was considered that the most suitable method of preparation was as a saturated solution.  Following a preliminary range-finding test,Desmodesmus subspicatus was exposed to a solution of the test item at a concentration of 100% v/v saturated solution (six replicate flasks) for 72 hours. Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group, using a Coulter®Multisizer Particle Counter. Exposure o fDesmodesmus subspicatus to the test item gave EC50values of greater than 100% v/v saturated solution. The No Observed Effect Concentration was determined to be 100% v/v saturated solution