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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

IC50 3h > 100 mg/l

Key value for chemical safety assessment

EC50 for microorganisms:
100 mg/L

Additional information

The inhibitory effect of the substance under registration (CAS 27344-06-5) on aerobic waste-water bacteria was investigated in a respiration test, according to OECD Guideline for Testing of Chemicals No. 209. The test article showed only a slight inhibition (6.3 %) of the respiration rate up to a concentration of 100 mg/l, therefore the IC50 was determined > 100 mg/l (Ritter A., 1989).

For completeness sake, supporting studies were reported on analogous dihydroxyethyl derivatives belonging to the category of Stilbene Fluorescent Whitening Agents: the dihydroxyethylamino derivative disulphonated sodium salt (CAS 4193-55-9) and thedihydroxyethylamino derivativetetrasulphonated sodium salt (CAS 16470-24-9).

The chemical similarity has been already described in previous endpoint and their water solubilities are lower and higher than the substance under registration (see also the Category Justification Report attached to the section 13).

All of those studies demonstrate that the substance does not inhibit the degradation activity of activated sludge in concentrations higher or equal to 100 mg/l.