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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

3h EC50 (activated sludge, domestic) = 680 mg/L (respiration inhibition test, EU Method C.11)

Key value for chemical safety assessment

EC50 for microorganisms:
680 mg/L

Additional information

Since no reliable studies on toxic effects of C12-16AS Na (CAS 73296-89-6) 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. A key study on microorganisms was performed with C12-18AS Na (CAS 68955-19-1). Since the toxicity of alkyl sulfates is dependent on the carbon chain length reaching its maximum at the C14/C15 carbon chain, it is expected that the toxic effects of the C12-18AS Na will be comparable to 12-16AS Na. The respiration inhibition test for C12-18AS Na (CAS 68955-19-1) with activated sludge was conducted according to the EU Method C.11 and is GLP compliant. An EC50 of 680 mg a.i./L was reported for the respiration rate after 3 h of exposure. Due to structural and property similarities with the tested category members it can be concluded that the above results apply also to C12-16AS Na (CAS 73296-89-6). The 3-hour EC50 value of 680 mg/L was used for the PNEC STP derivation.

Moreover, a study was performed with C12AS Na (CAS 151-21-3) using activated sludge from a municipal sewage treatment plant (Dutka 1983). 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. Additionally, a GLP test according to DIN 38412 part 8 with Pseudomonas putida using C12-14AS TEA (CAS 90583-18-9) is available (Guhl 1992). In this study, the growth inhibition of Pseudomonas putida was recorded after approximately 16 hours of exposure. The 16-h EC10 value was determined to be 1084 mg a.i./L (nominal concentration). Finally, a reliable study with Pseudomonas putida is available for C16-18AS Na (CAS 68955-20-4; Steber 1988). The study followed the procedure of cell multiplication inhibition test according to Bringmann and Kühn (1977). The growth inhibition of Pseudomonas putida was recorded after 18 hours of exposure to the test substance. The 18-hour NOEC value was determined to be 550 mg a.i./L (nominal concentration).