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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study
Qualifier:
according to
Guideline:
OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)
Deviations:
no
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic, non-adapted
Duration of test (contact time):
28 d
Initial conc.:
20 mg/L
Based on:
other: TOC
Reference substance:
benzoic acid, sodium salt
Key result
Parameter:
% degradation (O2 consumption)
Value:
64
Sampling time:
28 d
Details on results:
CO2 evolution:
day4: 1%
day 7: 3%
day14: 28%
day 21: 64%
day28: 64%
Results with reference substance:
100% DOC after 28d
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
2-Octyl-1-dodecanol (Rilanit G20) is regarded to be readily biodegradable within 28 d (fulfilling the 10d-window) by 64% CO2 evolution.
Executive summary:

2-Octyl-1-dodecanol (Rilanit G20) was tested for readily biodegradability in the CO2 -Headspace test (OECD 310). After 28 d and fulfilling the 10d-window 1-Dodecanol, 2-octyl- (Rilanit G20) reached 64 % CO2. Therefore, 1-Dodecanol, 2-octyl- (Rilanit G20) is regarded to be readily biodegradable.

Description of key information

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Reliable measured data show that Guerbet alcohols of chain lengths up to C32 are readily biodegradable.

At carbon chain length of C16 the data show that the pass level for ready biodegradation was reached within the 10-day window with removal levels up to 96%. Shorter and longer carbon chain lengths (for example, C12 and C20) achieved ready test pass levels but not in all cases within the 10d window. The C24 Guerbet alcohol showed biodegradation rates of 84% after 28 days and reached the pass levels of the 10 day window. Guerbet alcohols with chain lengths of C32-36 showed only degradation of up to 47%. The data demonstrate a decrease in biodegradation rates with increasing chain length if the biodegradation test is conducted according to the standard procedure. It is assumed that this decrease is associated to the decrease in water solubility and the resulting decrease in bioavailability. This assumption is supported by the biodegradation tests of the C24- and C32-Guerbet alcohols. In this test the substance was administered to test system by applying it on the whole surface of the test flask. With this increased surface and resulting improvement of bioavailability higher biodegradation rates were achieved than for the C20 -Guerbet alcohols. Therefore the whole category of the Guerbet alcohols with carbon chain lengths of C12 -C32 is considered to be readily biodegradable.