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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: screening test, other
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
as a UVCB and natural complex substance, it is considered a constituents approach. This mother tincture contains about 65% (v/v) of ethanol.
Qualifier:
according to guideline
Guideline:
EU Method C.5 (Degradation: Biochemical Oxygen Demand)
GLP compliance:
not specified
Specific details on test material used for the study:
wastewater from domestic sewage
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic (adaptation not specified)
Details on inoculum:
wastewater from domestic sewage
Duration of test (contact time):
>= 5 - <= 20 d
Details on study design:
Three concentrations tested (3, 7 and 10 mg/l) with at least two in duplicate. Tested concentrations gave a BOD of 3 to 30mg/l. Dissolved oxygen measured periodically (5 times in 20 days).
Parameter:
other: BOD protocol
Value:
74
Sampling time:
5 d
Remarks on result:
readily biodegradable based on QSAR/QSPR prediction
Parameter:
other: BOD protocol
Value:
74
Sampling time:
10 d
Remarks on result:
readily biodegradable based on QSAR/QSPR prediction
Parameter:
other: BOD protocol
Value:
95
Sampling time:
15 d
Remarks on result:
readily biodegradable based on QSAR/QSPR prediction
Details on results:
Measured COD was 1.99 mg O2/mg.
Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
In aerobic conditions using adapted wastewater from domestic sewage, degradation was 74% after 5 days rising to 95% by day 15 and in similar conditions in synthetic seawater, ethanol was 45%
degraded after 5 days rising to 75% by day 20 (Price, 1974). Biodegradation in a study to a MITI protocol showed degradation of 89% after 14 days (>70% after 10 days, CERI, 2004) and >90% within 10 days (Birch, 1991).
Activated domestic sludges were capable of aerobically oxidizing ethanol, as measured by BOD, which was 37.3% of maximum after 1 day (Gerhold, 1966).

Description of key information

As a UVCB, this mother tincture (TM) is a mixture of several components. All major constituents of TM are readily biodegradable. Ethanol is readily biodegradable at 74% after 5 days rising to 95% by day 15 (source OECD SIDS). Therefore, the TM can be considered as a readily biodegradable mixture.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information