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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The ready biodegradability of the test substance itself was examined to the OECD 301 F (Ready Biodegradability: Manometric Respirometric Test). The test substance was degraded 84 % in 27 days and the 10 days window criteria was fulfilled. The test substance was found to be readily-biodegradable under test conditions. The ready biodegradability of the test item was further assessed using a read-across category approach based on grouping of substances. The surrogate test substances were found to be readily biodegradable and a weight of evidence approach was applied.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

The ready biodegradability of the test substance 3-methylbutan-1-ol was examined according to the OECD 301 F (Ready Biodegradability: Manometric Respirometric Test). The biodegradation of the test surrogate substance was followed by exposing it to the active sludge of a domestic waste water treatment plant also non-adapted. The concentration of the test substance was 100 mg/L. The test substance was degraded 84 % in 27 days and the 10 days window criteria was fulfilled. The test substance 3-methylbutan-1-ol was found to be readily-biodegradable under test conditions.

 

Supplementary the ready biodegradability of the surrogate test substance pentan-1ol was examined according to ISO DIS 9439 (Ultimate aerobic biodegradability – Method by Analysis of Released Carbon Dioxide). The biodegradation of the test substance was followed by exposing it to the active sludge of a domestic waste water treatment plant, non-adapted. The active sludge concentration was 150 mg/L. For this reason the OCED criteria for readily biodegradability could not be applied, although the 10 day window was fulfilled. The concentration of the read across test substance was 59 mg/L. As reference compound (procedure control), aniline was tested simultaneously under the same test conditions. The aniline was biodegraded by an average of > 60 % after 14 days. The validity criterion was met. The read across substance was degraded by 80 - 90 % (CO2 evolution) and 90 -100 % (DOC removal) after 28 days. The read across substance was found to be biodegradable under the test conditions. The 10 days window criterion was also fulfilled.

 

In addition the biodegradability of the other category members was assessed. The ready biodegradability of the surrogate test substance pentanol branched and lineal was examined according to OECD 310 (Ready biodegradability – CO2 in Sealed Vessels (Headspace Test). The biodegradation of the surrogate test substance was followed by exposing it to the active sludge of a domestic waste water treatment plant, non-adapted. As reference compound (procedure control), aniline was tested simultaneously under the same test conditions. The aniline was biodegraded by an average of 78 % (TIC/TOC) after 14 days. In consequently the validity criteria was met. The test substance was degraded 100 % in 18 days. The surrogate test substance pentanol branched and lineal was found to be readily-biodegradable under the test conditions.

 

Further the ready biodegradability of the read across substance 2-methylbutan-1-ol was investigated according to OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test). The biodegradation of the surrogate test substance was followed by exposing it to the active sludge of a domestic waste water treatment plant, non-adapted. As reference compound (procedure control), aniline was tested simultaneously under the same test conditions. The aniline was biodegraded by an average of 83 % after 14 days. The validity criterion was met. The test substance was degraded 93 % in 18 days, therefore the surrogate test substance 2-methylbutan-1-ol was found to be readily-biodegradable under the test conditions.

 Based on the available data and the test results of the other read-across category members the target substance is considered to be readily biodegradable.