Dodecanoic acid, ester with oxybis[propanediol]

Endpoint summary

Additional information

Reaction products of lauric acid and oxybis(propanediol) is an UVCB substance composed of different C12 fatty acid esters, whose environmental fate was basically assessed using QSAR calculations for its main components: diglycerol monolaurate and diglycerol dilaurate.

 

Fatty acid esters are ubiquitous and dynamic in the environment and are completely metabolised in water and soil by microorganisms. They occur in the environment both naturally and from the use by man. Fatty acid esters are commonly found in essential oils or pheromones. Fatty acid esters are enzymatically metabolized in organisms to Fatty acids and fatty alcohols, which are integral parts of cell membranes of every living organism from bacteria and algae to higher plants and animals. Each of these organisms contains fatty acids also as part of their food reserves and they also consume fatty acids to produce energy required for anabolic and catabolic metabolism.  Microbial metabolism is the primary route of degradation in the environment.

 

In water aliphatic fatty acid esters are abiotically stable (US-EPA; 2004, 2010). Based on the expected ready biodegradability and the molecular structure, hydrolysis is not a relevant degradation pathway of the test substance as confirmed by QSAR calculations for its main components (DT50 [pH 7] = 2.6 – 7.1 yrs).

 

Based on QSAR estimations for the main components the test substance is susceptible to indirect photodegradation in air. The estimated half time for the reaction with OH-radicals is in the range of 6.30 - 7.16 hours. However, photodegradation is not expected to be an important environmental fate process since the test substance is unlikely to exist in the vapour phase in the atmosphere.

 

Experimental results for a similar UVCB substance as well as reliable QSAR predictions for the main components of the test substance indicate that the test substance can be considered as readily biodegradable. This assumption is consistent with the hazard assessment presented in the US-EPA HPV Aliphatic Diester Category (US-EPA, 2010), where aliphatic diesters with a carbon chain length in the range of C4 – C13 are judged to be readily biodegradable.

 

Adsorption potential to sediment and soil is considered to be moderate based on log Koc values calculated for its main components in the range of 1.84 – 3.89 (MCI method). Volatilization is not expected to be a significant transport process for the test substance in the environment (9.2* E-12 – 9.0*E-15 Pa*m3/mole, calculated for its main components).

 

The bioaccumulation potential of the test substance is considered to be low, as BCF values for its main components were calculated to be in the range of 30.2 – 515 L/kg (regression-based estimate). The conclusion on low bioaccumulation is in line with the recent assessment of substances as defined by the US-EPA HPV Aliphatic Diester Category (US-EPA, 2010).

US-EPA. 2004. Monoester Category of the Aliphatic Esters Chemicals (Test Plan and Robust Summaries for Substances in the HPV Test Plan). High Production Volume (HPV) Chemical Challenge Program (201-14870A and 201-14870B). accessed: http://www.epa.gov/hpv/pubs/summaries/alipestr/c13466tc.htm (04 Nov 2011)

US-EPA. 2010. Diesters Category of the Aliphatic Esters Chemicals (Test Plan and Robust Summaries for Substances in the HPV Test Plan). High Production Volume (HPV) Chemical Challenge Program (201-16837A and 201-16837B). accessed: http://www.epa.gov/hpv/pubs/summaries/alipestr/c13466tc.htm (04 Nov 2011)