Reaction mass of N, N'-hexane-1,6-diylbis [12-hydroxyoctadecanamide] and 12-hydroxy-N-[6-[1-oxoalkyl)amino] hexyl ] octadecanamide

Biodegradation in water: screening tests

Description of key information

AD-1000 is not readily biodegradable neither under the conditions of the modified Sturm test nor under the conditions of a head space test. 
QSAR's run on both components of the test substance revealed that the the Boethling criteria for ready biodegradation predicted not readily biodegradable whereas the MITI models predicted readily degradability of the substance.
Definitive conclusions with regard to ready biodegradation cannot be drawn from the non-interpretable and non-conclusive results. The substance, however, is deemed to biodegrade fast.

Additional information

AD-1000 was experimentally tested for biodegradation in two different studies. In a modified Sturm test (according to test guidelines OECD 301 B and EC C.4) with activated sludge under aerobic conditions only 3% degradation of AD-1000 was observed after 28 days. In a head space test (according to test guideline OECD 310) with adapted activated sludge under aerobic conditions 5% degradation of AD-1000 was observed after 28 days. It is thus concluded that AD-1000 is not readily biodegradable under the conditions of the modified Sturm test and the head space test. The results of these tests, however, cannot be interpreted because the tested concentrations in both tests were far above the maximum water solubility. Thus, in view of lack of the optimal contact between the test substance and the medium in the test, no definitive conclusions can be drawn with respect of biodegradability of the test substance.

Further testing for biodegradability by the enhanced ready biodegradation test (ISO Guideline 10634) was deemed to be

technically not possible (see attached letter).

The QSAR model EPIWEB was used in order to gain supplementary information on the biodegradability because no definitive conclusions could be drawn with respect of biodegradability of the test substance based on the two experimental screening studies. The validity and applicability criteria, as described in the REACH guidance, of the QSAR estimation were not evaluated in detail. However, BIOWIN is a known and reliable calculation tool for this endpoint. The BIOWIN models revealed no conclusive evidence either on the ready biodegradation, but the estimations indicated that the substance biodegrades fast.

Definitive conclusions with regard to ready biodegradation cannot be drawn from the non-interpretable and non-conclusive results. The substance, however, is deemed to biodegrade fast.