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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

3h EC50 (activated sludge, domestic) = 135 mg/L (respiration inhibition test, similar to OECD 209)

Key value for chemical safety assessment

EC50 for microorganisms:
135 mg/L

Additional information

Since no reliable studies on toxic effects of C9-11AS Na (CAS 84501-49-5) to microorganisms are available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5, a read-across to other structurally related category members was conducted. The key study was performed with C12AS Na (CAS 151-21-3) using activated sludge from a municipal sewage treatment plant (Dutka 1983). Since the toxicity of alkyl sulfates is dependent on the carbon chain length, it is expected that the toxic effects of the C12 homologue will be representative for C9-11AS Na (CAS 84501-49-5). The non-GLP test was performed with C12AS Na according to a guideline similar to OECD 209. The EC50 values of 188 and 135 mg/L (nominal concentrations) were obtained for the endpoint respiration inhibition after 30 minutes and 3 hours of exposure, respectively. The 3-hour EC50 value of 135 mg/L was used for the PNEC STP derivation for C10-12AS Na (CAS 85049-86-1). In the supporting non-GLP study with CAS 151-21-3, Dutka and Kwan (1984) used synthetic activated sludge and measured respiration rate after 3 hours. The 3h IC50 value was 480 mg/L (nominal concentration).

Due to structural and property similarities with the tested category members it can be concluded that the above results apply also to C9-11AS Na (CAS 84501-49-5).