Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Four reliable screening tests (GLP compliant guideline studies) and a non-GLP result from the MITI database are available which show different results on the biodegradability of the substance. In the OECD Guideline 301 F test (Ready Biodegradability: Manometric Respirometry Test) with sludge from a municipal sewage treatment plant, 81.9% biodegradation was found after 28 days determined as O2 consumption and 60.1% determined as CO2 removal (West et al., 2007)). This test is a better simulation of realistic conditions than the other screening tests and will therefore be further used as key study in the assessment. It can be concluded that the substance is ready biodegradable.

Significant biodegradation was found in an OECD306 test with natural seawater after 64 days (West et al, 2007). Therefore tripropylene glycol is not expected to persist in water or marine environments.

Under the conditions of other screening tests (OECD301B, OECD301C and OECD301D with municipal inoculum) the test substance was not ready biodegradable (Shell Research, 1993, MITI, 1995, The Dow Chemical Company, 1991). However, in an OECD301D test with industrial inoculum, 69% of the theoretical oxygen demand was consumed after 28 days in reaction mixtures containing the industrial inoculum. These data suggest that some adaptation of the microorganisms may be required for biodegradation. Simulation studies with sediment and/or soil are not available.

The rate constant used in the assessment are (calculated with EUSES):

 

Degradation in the STP

24 d-1

Biodegradation in surface water

0.0462 d-1

Biodegradation in sediment

2.31E-03 d-1

Biodegradation in soil

0.0231 d-1