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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Readily biodegradable: 79.5% in 28 days (OECD 301B)

Key value for chemical safety assessment

Additional information

No experimental data evaluating the biodegradation potential of Glycerides, C12-18 mono- and di- (CAS No. 91052-49-2) are available. Therefore, biodegradation data from a structurally related category member, Glycerides, C12-18 di- and tri- (CAS No. 91744-28-4) are used as read-across in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5. Both substances are esters formed from the combination of C12-18 fatty acids and glycerol. Due to differences on the degree of esterification of these substances (mono and diester for CAS No. 91052-49-2, and di and triester for CAS No. 91744-28-4), a higher biodegradation rate can be expected for the target substance. Generally, larger and branched molecules are considered as a worst-case approach, since the chain length and substitutions are determining factors for biodegradation of fatty acid alcohol esters (Bozcar et al., 2001; Dias and Alexander, 1971). As biodegradation will tend to increase at higher degree of esterification, reading across from Glycerides, C12-18 di- and tri- represents a worst-case scenario for the target substance and therefore it is justified.

A study evaluating the potential for ready biodegradability of Glycerides, C12-18 di- and tri- (CAS No. 91744-28-4) is available (Flach, 2012). The test was conducted according to OECD Guideline 301B, under GLP conditions. Activated sludge microorganisms were exposed to the test substance for a period of 28 days, and biodegradation followed by measuring the CO2 production in the test vessels. After 28 days, the test substance reached 79.5% biodegradation, and therefore, it can be considered as readily biodegradable. The results obtained in the toxicity control (55% biodegradation within 14 days) show that Glycerides, C12-18 di- and tri- is not toxic to and therefore non-inhibitory of activated sludge microorganisms activity.

 

Based on the results of the test performed on the structurally related analogue substance (in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5), Glycerides, C12-18 mono- and di- (CAS No. 91052-49-2) can be regarded as readily biodegradable.