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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

Linear CaDDBs is a readily biodegradable substance (see section 5.2.1). Toxicity to micro-organisms is not a required endpoint for readily biodegradable substances because the tests demonstrate there is no inhibition to microbial viability.

Key value for chemical safety assessment

Additional information

The study determined the toxicity of three commercial linear alkylbenzene sulphonate sodium salt (LAS) products to the activated sludge of a treatment plant basically operating on domestic sewage. A contact time of 3 hours instead of 15 minutes was chosen to better simulate the real residence time used in wastewater treatment plants (4-6 hours). The EC50values are far above maximum raw sewage concentrations of 6 -8 mg/L and therefore provide a high margin of safety. The 3-hour EC50range for the reference substance (3,5-dichlorophenol) ranged from 20-30 mg/L, within the valid range of 5-30 mg/L.