Reaction mass of methyl (9E,12E,15Z)-9,12,15-octadecatrienoate and methyl (9E,12Z,15E)-9,12,15-octadecatrienoate and methyl (9Z)-9-octadecenoate and methyl (9Z,12E,15E)-9,12,15-octadecatrienoate and methyl (9Z,12Z)-9,12-octadecadienoate

Biodegradation in water: screening tests

Description of key information

Weight of evidence: substance is readily biodegradable
1. Biodegradation: 80% (28-days; 10-day window met) readily biodegradable, OECD TG 301F (non-GLP), Firmenich SA 2009
2. Biodegradation: 77 – 82% (28-days; 10-day window not relevant to multi-constituent substance); readily biodegradable, CATALOGIC Kinetic 301F v.13.16, OASIS Catalogic v5.11.17, Firmenich SA 2015

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The weight of evidence indicates that the substance is 'readily biodegradable' and can be expected to exceed 60% degradation within 28-days. The 10-day window is less relevant to the multi-constituent substance-type as under OECD, 2006 definitions.

 

OECD TG 301F (non-GLP), 2009 - The ready biodegradability test was carried out according to OECD TG 301F guideline. The test substance, at a concentration of 96 mg/L in test 1 and at a concentration of 92 mg/L in test 2 was exposed to activated sewage sludge micro-organisms obtained from the secondary treatment stage of the sewage treatment which treats predominantly domestic sewage (Villette: Geneva, Switzerland) with culture medium in sealed culture vessels in diffused light at 22°C ± 1°C for 28 days. The sludge was diluted in the BOD bottles to 30 mg DW/L. The degradation of the test substance was assessed by the measurement of daily oxygen consumption on days 0 and 28 using an Oxitop control system. Control solutions with inoculum and the reference substance, sodium benzoate were used for validation purposes. The oxygen uptake was < 60 mg O2/L in all of the inoculum blank test systems. The test system met the validation criteria of the guideline. Sodium Benzoate attained 60% degradation within 14 days and 84% degradation after 28 days thereby confirming the suitability of the inoculum and test conditions. The mean biodegradation for duplicate test flasks at 28 days for the test substance was 80%. Under the conditions of this study the test substance is considered to be readily biodegradable. Applicant assessment of the data indicates: Whilst the 10-d window was achieved during the course of the study (10% achieved on day 2; in duplicate and >60% on day 9) it is noted by the applicant that for multi-constituent substances this criteria has less relevance. These substances are considered to be ‘readily biodegradable’ when they surpass the 60% limit criterion based on oxygen consumption within the 28-d period of the test. Reference: UN/SCEGHS/15/INF.35, 2008

 

(Q)SAR assessment, CATALOGIC Kinetic 301F v.13.16, 2015 - substance is readily biodegradable

Summary: BOD [28]= from 0.77 to 0.82

Substance will exhibit 77 – 82% biodegradation (BOD) at 28-d and exceeding the 60 % pass level set by the OECD Guidelines for testing of Chemicals (301).

Although the 10-day window criteria was not met for 7 of the constituents composing this multi-constituent substance, the nature of the substance (multi-constituent) precludes the application of a 10-day window when assessing the biodegradability of the substance as a whole (OECD, 2006). Additionally, this prediction is intended as supporting information in a weight-of-evidence approach that shows the substance to be readily biodegradable.