Fatty acids, C18-unsatd., dimers, mixed esters with oleic acid and trimethylolpropane

Biodegradation in water: screening tests

Description of key information

Readily biodegradable: 70-85% (O2 consumption) in 28 days (OECD 301F)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Six studies investigating the ready biodegradability of Fatty acids, C18-unsatd., dimers, mixed esters with oleic acid and trimethylolpropane (CAS No. 147256-33-5) are available. The key studies were conducted according to GLP and OECD guideline 301F under aerobic conditions using non-adapted effluent as inoculum, which is obtained from a STP predominately treating domestic sewage (Börner, 2000a, b). Based on O2 consumption a mean degradation of 85% and 70% was observed after 28 days. The first key studies reached a biodegradation 67% at the end of the 10-d window (Börner, 2000a). Hence, the substance is determined to be readily biodegradable according to OECD criteria. The second key study did not reach the biodegradation pass level of 60% within the 10-day window (Börner, 2000b). However, as the test substance is a mixture of constituents with different chain-lengths, sequential (instead of concurrent) biodegradation takes place. Thus, referring to Annex I to the OECD Guideline for The 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 considered for the test substance. Due to a degradation of > 60% within 28 days the test substance can be regarded as readily biodegradable.

This conclusion is supported by additional GLP guideline studies performed under aerobic conditions (Table 1). One study was conducted according to OECD guideline 301B using non-adapted activated sludge as inoculum (Häner, 2010). Based on CO2 evolution a mean degradation after 28 days was observed to be 94.5%. A further study was conducted according to ISO guideline 10708 (BODIS test) using STP effluent as inoculum (Küster, 1996). Based on O2 consumption a mean degradation of 69% was observed after 28 days. All available data are listed in the table.

Table 1: Biodegradation results for CAS No.147256-33-5

Biodegradation after 28 d [%]	Guideline	Inoculum	Result	Source
85	OECD 301F	STP effluent, non-adapted, domestic	readily biodegradable (10 -day window passed)	Börner, 2000a
70	OECD 301F	STP effluent, non-adapted, domestic	readily biodegradable (10 -day window failed)	Börner, 2000b
94.5	OECD 301B	Activated sludge, non-adapted, domestic	readily biodegradable (10 -day window passed)	Häner, 2010
69	ISO 10708	STP effluent, non-adapted, domestic	readily biodegradable (10 -day window failed)	Küster, 1996
82	OECD 301B	Activated sludge, non-adapted, domestic	readily biodegradable (10 -day window passed)	Junghans, 2009
73	OECD 301B	Activated sludge, non-adapted, domestic	readily biodegradable (10 -day window passed)	Garrivier, 2010

Based on all available data, Fatty acids, C18-unsatd., dimers, mixed esters with oleic acid and trimethylolpropane is considered to be readily biodegradable according to the OECD criteria.