Registration Dossier
Registration Dossier
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EC number: 910-245-3 | CAS number: -
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
Description of key information
Key value for chemical safety assessment
- EC50 for microorganisms:
- 22 mg/L
Additional information
Sodium Hydroxide: source sodium hydroxide summary risk assessment report JRC EC 2008
In a test system with the freshwater ciliated protozoan Tetrahymena thermophila, NaOH is used as a positive control. At the NOEC (EC10) of 167 mg/l the calculated pH value was 11.6, assuming that the dilution medium has no buffer capacity.
The inhibition of the bioluminescence of the marine bacterium Photobacterium phosphoreum by NaOH has been measured with the Microtox test system, resulting in a 15-minutes EC50 of 22mg/l.
Sodium Silicate:
The toxicity of a sodium silicate solution (MR 3.46, 34.8 wt%) has been determined with a growth inhibition test in compliance with German standards and GLP using the bacterium Pseudomonas putida (Hanstveit 1989). The 18 h toxicity threshold (EC10, 10 % inhibition) of a neutralised silicate solution of pH 7.6 - 7.8 was > 3480 mg active matter/L, the highest concentration tested, while for the unneutralised solution (pH 7.9 - 10.4) effects were found at concentrations above 348 mg active matter/L. In a further GLP guideline study complying with German standards corresponding to OECD 209, the toxicity to Pseudomonas putida was tested in an oxygen consumption inhibition test. Concentrations of a sodium silicate solution (MR 3.0, 34.54 wt%) of up to 3454 mg active matter/L at pH 8.0 - 11.1 did not cause toxic effects (Kirch 1993).
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