1-Propanamine, 3-(C9-11-isoalkyloxy) derivs., C10-rich, acetates

Biodegradation in water: screening tests

Description of key information

The test substance  was oxidised by 68% after 28d in the Closed Bottle test.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

In order to assess the biotic degradation, a ready biodegradability test was performed which allowed the biodegradability to be measured in aerobic aqueous media. The study was performed with a Closed Bottle Test (CBT, according to OECD TG 301D) with 3-((C9-11-iso-,C10-rich)alkyloxy)propan-1-amine. The results of this study have been read-across to the 3-((C9-11-iso-,C10-rich)alkyloxy)propan-1-amine acetate. The read-across is justified because the biodegradation rate of an amine and its acetate will be the same in the environment.

The ready biodegradability was determined in a slightly modified Closed Bottle Test (OECD TG 301D) in compliance with GLP. Ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification (omission did not result in nitrogen limitation as shown by the biodegradation of the reference compound). Humic acid (2.0 mg/L) was added to reduce the toxicity of the test substance to the micro-organisms.

 

3-((C9-11-iso-,C10-rich)alkyloxy)propan-1-amine did not cause a reduction in the endogenous respiration in the presence of humic acid. The test substance is therefore considered to be noninhibitory to the inoculum. 3-((C9-11-iso-,C10-rich)alkyloxy)propan-1 -amine was oxidised 68% at day 28 in the Closed Bottle test. Hence this compound should be classified as readily biodegradable.

The test is valid as shown by an endogenous respiration of 1.4 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded 76% of its theoretical oxygen demand after 14 days. Finally, the most important criterion was met by oxygen concentrations >0.5 mg/L in all bottles during the test period.

1-Propanamine, 3 -(isodecyloxy)- is a surfactant. Surfactants are chemicals in which a hydrophilic group is linked to a hydrophobic moiety. Biodegradation of both moieties of surfactants requires the concerted action of at least two microorganisms as a single organism usually lacks the full complement of enzymatic capabilities (van Ginkel, 1996). In ready biodegradability tests, the two moieties of fatty amine derivatives are degraded sequentially.The biodegradation of the two moieties of 1-propanamine, 3-(isodecyloxy)- may be fully in line with the 10-day window criterion when judged as separate chemicals whereas the sum of the biodegradation curves is not. The biodegradation curve of 1-propanamine, 3-(isodecyloxy)- should therefore not be used to assess a 10-day window effect.

It can be concluded that the substance fulfills the criterion for readily biodegradability based on the results of the OECD301D study (GLP, reliability 1).