Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Diethylenetriamine is a liquid with moderate vapor pressure (21.3 Pa at 20 °C); however, due to its miscibility with water, has low potential to volatilize from water. The substance has a very low octanol-water partition coefficient (log Kow = -1.58), which also inidcates a low potential for uptake in aquatic organisms. Diethylenetriamine possesses three amino groups, which will occur as charged species (cationic) under pH conditions encountered in the environment. This cationic character is responsible for its expected high affinity for adsorption to soil/sediment, by a cation exchange mechanism. The substance is not susceptible to hydrolysis or direct photolysis in the aquatic environment. Therefore, biodegradation is expected to be the dominant process affecting fate of this substance in the environment. Several biodegradation screening tests of inherent or ready biodegradability have indicated little or no biodegradation of the substance. However, evidence from these studies suggests that results were confounded by toxicity/inhibition of the microbial inocula by the relatively high concentrations of diethylenetriamine tested. In one closed-bottle test which employed a low test substance to inoculum ratio, ready biodegradability was demonstrated after a prolonged lag phase. In addition, there is evidence from other studies to suggest that a relatively long acclimation period may be required for previously unexposed inocula to attain the ability to degrade the substance. Studies using low concentrations of the substance, and/or extended incubation periods, have shown the substance to have potential for ultimate biodegradability in the environment. This potential is verified by simulation tests in sewage, soil, and lake water samples, where rapid biodegradation was observed. As such, the substance is not regarded as being persistent in the environment.