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Biodegradation in water: screening tests

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biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
according to guideline
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
Inoculum or test system:
activated sludge, domestic, non-adapted
Duration of test (contact time):
29 d
Initial conc.:
32.8 mg/L
Based on:
test mat.
Initial conc.:
32.7 mg/L
Based on:
test mat.
Reference substance:
% degradation (CO2 evolution)
Sampling time:
28 d
Details on results:
All validity criteria were met. Negative degradation values were calculated at some sampling dates, wich is due to measurement uncertainties.
The test item showed no degradation in the biotic flasks, but nearly 50 % degratation in the abiotic flask. This error was due to a biofilm which was detected in the air supply tubes. Therfore the abiotic control was regarded as invalide, and the test item was assessed taking into accont the biotic flasks only. Absolutely no degradation was detected in the biotic flasks.
The degradation in the toxic flask was 42% after 14 d. Therefore the test item can be stated as "not toxic towards the inoculum in a concentration of 32.5 mg/L (limit value: 25 %).
Validity criteria fulfilled:
Interpretation of results:
under test conditions no biodegradation observed
not biodegradable
not toxic towards the inoculum
Executive summary:

10 day window:                                               none

degration at the end of the 10 day window:      0 % pass level: 60%

degration at the end of the test:                        1 %

Description of key information

The test item N,N'-hexane-1,6-diylbis(hexahydro-2-oxo-1H-azepine-1-carboxamide) is considered as "not readily" biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

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