Glycerides, C18-36

Biodegradation in water: screening tests

Description of key information

Readily biodegradable: 61% (O2 consumption) after 28 d (OECD 301F)

Additional information

One experimental study is available investigating the ready biodegradability of Dub TGI 24. The study was conducted according to OECD 301F using non-adapted activated sludge from a municipal sewage treatment plant. Two test concentration were used, 100 mg/L which correspond to 302 mg ThOD and 20 mg/L which correspond to 60 mg ThOD. The ThOD of the first test substance concentration (302 mg ThOD) is clearly above the demanded value of at least 50 – 100 mg ThOD. Therefore, the additional approach with 20 mg test item (60 mg ThOD) was conducted. The biodegradation after 28 days was recorded as 40% at 100 mg/L and 61% at 20 mg/L. As the first test substance concentration (100 mg/L) failed the treshold with 302 mg ThOD, the second approach (20 mg/L with 60 mg ThOD) was used for evaluation of the biodegradation of the test substance. Therefore a biodegradation of 61% (O2 consumption) was reported after 28 days, but the 10-day-window was failed. Since the test substance is an UVCB substance and consists of structurally similar constituents with [e.g. different chain-lengths, degree and/or site of branching or stereo-isomers], sequential (instead of concurrent) biodegradation of the individual structures can take place. All can be considered as readily biodegradable. Thus, referring to Annex I to the OECD Guideline for Testing of Chemicals ‘Revised introduction to the OECD guidelines for testing of chemicals, section 3’ (OECD, March 2006), the 10-day window should not be applied to this UVCB substance . Based on the degradation of >60 % within 28 days the substance can be regarded as readily biodegradable.