Reaction mass of (Z)-3-(9-octadecenyloxy)propane-1,2-diol and alpha-(Z)-octadec-9-en-1-yl-omega-hydroxy-di[oxy[(hydroxymethyl)-1,2-ethanediyl]] and alpha-(Z)-octadec-9-en-1-yl-omega-hydroxy-tri[oxy[(hydroxymethyl)-1,2-ethanediyl]]

Biodegradation in water: screening tests

Description of key information

OECD 301B, EU Method C.4-C, GLP, key study, validity 2:
84% biodegradation after 28 days. 
Readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

One valid key study is available to assess the biodegradation of Chimexane NB. This study was performed over a test period of 28 days with a non adapted activated sludge from a predominantly municipal plant according to OECD 301B and EU method C.4-C with GLP statement at Dr. U. Noack-Laboratorien.

The test item was tested at a concentration of 20 mg/L in duplicates, corresponding to a carbon content (TOC) of 13.0 mg C/L in the test vessels. The biodegradation of the test item was followed by titrimetric analysis of the quantity of CO2 produced by the respiration of bacteria. The degradation was stopped on day 28 by acidification of the test solutions. The last titration was made on day 29, after residual CO2 had been purged from the test solutions over a period of 24 hours. The percentage CO2 production was calculated in relation to the theoretical CO2 production (ThCO2) of the test item. The biodegradation rate was calculated for each titration time.

To check the activity of the test system, sodium benzoate was used as functional control. The percentage degradation of the functional control reached the pass level of 60% after 7 days and came to a maximum of 77% after 28 days.

In the toxicity control containing both test and reference item a biodegradation rate of 64% was determined within 14 days and it came to 76% after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

The biodegradation of Chimexane NB was 58% at the end of the 10-d window and 84% after 28 days. Since the 10d-window does not apply to test substances representing a mixture of homologous compounds as technical surfactants, Chimexane NB is considered as readily biodegradable.

All validity criteria were fulfilled except the IC content of the test item suspension in the mineral medium at the beginning of the test. It was 5.9% of the TC instead of <5.0%. The slightly higher IC content has no impact on validity and integrity of the study.