Sulfuric acid, mono-C12-14-alkyl esters, potassium salts

Biodegradation in water: screening tests

Description of key information

Readily biodegradable according to OECD criteria: 79.8 % after 28 days based on CO2 evolution (OECD 301 B).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Since no reliable biodegradability tests are available for C12-14AS K (CAS 1268005-68-0), in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5, a read-across to another structurally related category members was conducted. Read-across data on the following substances was used: C14AS Na (1191-50-0), C12AS Na (CAS 151-21-3), a similar C12-14 mixture: C12-14AS TEA (CAS 90583-18-9) and C12-16AS Na (73296-89-6).

One GLP study showing ready biodegradation of C14AS Na (CAS 1191-50-0) is available (Hansmann 1995). This key study was performed according to OECD 301 B guideline using activated, domestic, non-adapted sludge as inoculum and the initial concentration of the test substance 11 mg/L as TOC. Biodegradation measured as CO2 evolution was greater than 60% after 10 days. The final level of biodegradation after 28 days was 79.8%. Based on these results, C14AS Na is readily biodegradable, passing 10-day window.

For the C12AS Na homologue (CAS 151-21-3), a GLP-guideline study according to OECD guideline 301 B is available (Brunswik-Titze 2005).  In this study, activated, non-adapted domestic sludge was used as inoculum and the initial concentration of the test substance was 20 mg/L as DOC. Based on the CO2 evolution measurements, the biodegradation reached 95% after 28 days and the 10-day window was passed. The substance therefore can be considered as readily biodegradable. Another, supporting study is available for CAS 151-21-3 (Börner 1996). This GLP test was performed according to OECD 301 D guideline using effluent of domestic sewage treatment plant as inoculum. Two concentrations of the substance were tested: 2 mg/L and 5 mg/L. By measuring O2 consumption, the substance was evaluated to be readily biodegradable. On day 28 biodegradation reached 97% and 94% for the concentrations of 2 mg/L and 5 mg/L respectively, passing the 14-day window in both cases.

Three reliable ready biodegradability tests are available for C12-14AS TEA (CAS 90583-18-9). The EU C.4-A method test was performed according to GLP guideline (Diefenbach 1995) using activated, domestic, non-adapted sludge as inoculum. The initial concentration of the test substance was 13.58 mgL as DOC. The biodegradation reached 87% after 7 days and 95% after 28 days based on DOC removal. Another GLP test is available for C12-14AS TEA (CAS 90583-18-9), performed according to modified OECD screening method (Richterich 1991). The initial concentration of the test substance was 10 mg/L (given as carbon). Biodegradation reached 95% after 10 days and 98% after 28 days based on DOC removal. Third, non-GLP test available for C12-14AS TEA (CAS 90583-18-9) was performed according to OECD 301 E guideline (Henkel, 1999). Municipal sewage treatment plant effluent was used as inoculum and the initial concentration of the test substance was 10 mg/L as DOC. Biodegradation reached 72% after 3 days and 98% after 28 days measured as DOC removal.

The biodegradability of C12-16AS Na CAS (73296-89-6) was investigated in a GLP guideline study according to OECD 301 B (Clarke 2005). Activated, domestic, non-adapted sludge as was used as inoculum and the initial concentration of the test substance was 10 mg/L as DOC. After 28 days of exposure the test substance was completely biodegraded in 100% passing the 10-day window.

Due to structural and property similarities with the tested category member these results also apply to C12-14AS K (CAS 1268005-68-0) which is considered to be readily biodegradable according to OECD criteria.