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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Several GLP and non-GLP studies according or similar to OECD guidelines 301F, 301E and 302B are available for propylene glycol methyl ether acetate.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

In the manometric respirometry test (OECD GL 301F) the time required to achieve 10% degradation of propylene glycol methyl ether acetate was 1.3 days, while the average extent of biodegradation at the end of the 10 day-window was 83%. Propylene glycol methyl ether acetate can be considered as readily biodegradable based on the results of this study. In the OECD GL 301E (Closed Bottle Test) the results of the abiotic control showed a 31% loss of DOC after 28 days. According to the authors, this loss is considered to be due to adsorption of test material to the glassware and/or the cellular material present from the poisoned inoculum. Therefore the loss of DOC in the other test vessels cannot be attributed to microbial degradation alone. The degradation of 70% reported was obtained after correction taking into account the loss observed in the abiotic control. The 10-day window criteria is not met. The Zahn and Wellens test (OECD GL 302B) showed that propylene glycol methyl ether acetate is inherently biodegradable. It was considered valid with restrictions because industrial sewage was used as inoculum. In industrial sewages, adapted microbial populations are more likely to be present than in domestic sewages. A biodegradation test - not conducted according to the standard OECD guideline - showed biodegradation from 70.5% to 93.4% after 45 days at different substance concentrations. The inoculum used in this study was an acclimated sludge. Therefore, this test is considered to be valid with restriction. Based on the result of the manometric respirometry test, propylene glycol methyl ether acetate is considered to be readily biodegradable. The other studies support this conclusion.