Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

MICROBIAL METABOLISM

Pseudomonas MA3 is capable to use dodecyldimethyl amine as sole carbon and energy source oxidizing and cleaving the substance to dodecanal, dodecanoic acid and dimethylamine. Dodecanoic acid as a fatty acid is subsequently biodegraded by beta oxidation. The C alkyl - N bond is cleaved with help of a dehydrogenase. The metabolites dodecanal and dodecanoic acid were identified using specific enzyme inhibitors to stop further metabolism. Dimethylamine was determined by GC.

Finally the intermediate metabolites will be mineralised which means that Dodecyldimethylamine is ultimately biodegraded.

BIODEGRADATION IN WATER: SCREENING TESTS

Reliable screening studies on biodegradation are available for eight out of ten DMA category members. These altogether 15 studies (4x RL 1, 11x RL 2) were performed according to OECD 301 guidelines and consistently demonstrated ready biodegradability of DMA.

BIODEGRADATION IN WATER AND SEDIMENT: SIMULATION TESTS

Biodegradation in Sewage Treatment Plants

One Key studies is available for C12-14 DMA sufficiently reported to demonstrate a elimination of >99.6% in an OECD303A Test. This result is supported by studies form the substances HYEQS and C20/22 ATQ. A supporting study is also available for Amines, Coco alkyl (C12-18-(even numbered)-alkylamines). These studies conclusively show that DMA category members will be fast and effectively eliminated in STP firstly by adsorption on particulate matter and secondly by immediate and effective biodegradation by more than 90% in the plateau phase.

Biodegradation in Surface water

In a reliable River Water Die Away test with the radio labelled supporting substance HYEQS the first order rate constant for primary biodegradation was 1.13 day-1, and the rate constant for mineralization was 0.09 day-1. Within 21 days 80% evolved as CO2. Biodegradation in Sediment

No studies in sediment are available but the half-life in soil (see IUCLID section 5.2.3) of 16.9 d at 12 deg C can be used instead.

BIODEGRADATION IN SOIL

Concluding from the reliable (without restriction) key study performed according to OECD 307 and compliant to GLP (RL 1) DMA category members are expected to degrade rapidly and ultimately in soil: A median (3 soils) half-life of 8.9 d at 20 degree C was determined for supporting substance hexadecanamine and found to be applicable for DMA category. This corresponds to a median half-life of 16.9 d at an environmental temperature of 12 degree C. It is important to note that despite the fact that cationic surfactants sorb considerably biodegradation rate is still high meaning rapid biodegradation. This experimental results do not support the assumption given in REACH Guidance R.16 Table R16.6 that the biodegradation half-life in soil is as lower as higher the sorption is.