Fatty acids, C14-18 and C18-unsatd., branched and linear, esters with neopentyl glycol

Biodegradation in water: screening tests

Description of key information

Readily biodegradable: 60.4% (CO2 evolution) in 28 days

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Five ready biodegradation studies are available for Fatty acids, C14-18 and C18-unsatd., branched and linear, esters with neopentyl glycol (CAS No. 85005-25-0), of which three were used for the assessment.

The key ready biodegradability study carried out with Fatty acids, C14-18 and C18-unsatd., branched and linear, esters with neopentyl glycol (CAS No. 85005-25-0), was performed following the OECD Guideline 301 B (Bouillon, 2003). Activated sludge from the aeration tank of a municipal wastewater treatment plant was used as inoculum. During the 28-day test period, biodegradation reached 60.4%, based on CO2 evolution. 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 according to the OECD criteria.

Two supporting studies carried out with Fatty acids, C14-18 and C18-unsatd., branched and linear, esters with neopentyl glycol (CAS No. 85005-25-0), were reported to be performed following the OECD Guideline 301 B (King, 1993). However, the described procedure for these studies rather follows the OECD Guideline 310 (adopted 2006, i.e. after this study). Secondary effluent of an unacclimatised activated sludge plant was used as inoculum. During the 28-day test period, biodegradation reached 72.8% and 73.7%, based on CO2 evolution, in the two tests. 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.

A further supporting study carried out with Fatty acids, C14-18 and C18-unsatd., branched and linear, esters with neopentyl glycol (CAS No. 85005-25-0) was conducted according to OECD guideline 301 B (Sacker, 2006). Non-adapted domestic activated sludge was used as inoculum. After the 28-day test period biodegradation reached 89% and 49% for the two replicates. Since the difference between replicates is above 20%, this test is not valid and was judged unreliable. Nevertheless, it supports the biodegradability of the test substance.

An additional supporting study carried out with Fatty acids, C14-18 and C18-unsatd., branched and linear, esters with neopentyl glycol (CAS No. 85005-25-0) was conducted according to the guideline CEC L-33-A-93, which investigates primary biodegradation (Croda, 1996). 79.8% biodegradation was reported for the 21-day test period. Due to the non-standard guideline and the lack of detailed information on the test procedure, the reliability of this test cannot be properly assessed. Nevertheless, this study also supports the biodegradability of the test substance.

In conclusion, Fatty acids, C14-18 and C18-unsatd., branched and linear, esters with neopentyl glycol (CAS No. 85005-25-0) can be considered readily biodegradable according to OECD criteria.