Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Tris(2 -butoxyethyl)-phosphate (TBEP) is moderately soluble in water (663.5 mg/L at 20°C). Hydrolysis is not expected to be a significant abiotic degradation process at environmental pH based on theoretical investigations.

In addition, based on screening data, TBEP is readily biodegradable. Data on the mechanisms of biotic transformation are not available. The available information suggests that elimination in sewage treatment plant is significant and that biodegradation in the environment is fast. Information about other possible abiotic degradation processes (hydrolysis, photo transformation in water) are not available but the biodegradation process is expected to be the main degradation pathway.

A few information is available on the stability of TBEP in air. It is expected to be rapidly degraded in air due to photo oxidation processes (half-life about 1 hour).

In addition, TBEP exhibits a low vapour pressure (1.52 x 10^-5 Pa at 25°C). Therefore if released in the environment TBEP is not expected to go to the air compartment.

Anyway, known as a flame retardant, TBEP has been detected in environmental surface water and sediments in several studies (See Environmental Data Section). The adsorption coefficient of TBEP suggests that it may adsorb on the soil and the sediment compartments. Some model calculation estimate that about 81% may be found in soil and 16% in water if released via effluent. However this is a worst case estimation for the soil compartment as this does not take into account any biodegradation process. Other calculation taking into account STP removal estimate 84.8% removal in STP and the 12.3% released to water and 2.86% released to sludge. Therefore, taking into account its readily biodegradability, the low adsorption to soil and sediment, TBEP is not considered of concern for the soil compartment and the sediment compartment.

Finally, based on a BCF value in fish of 5.8, TBEP is not considered as bioaccumulable. Therefore taking into account the moderate solubility, the medium mobility in soil and the possible degradation, the terrestrial compartment is not considered as a compartment of concern for TBEP.