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Environmental fate & pathways

Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2001-03-02 to 2001-03-27
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic (adaptation not specified)
Duration of test (contact time):
28 d
Initial conc.:
40.2 mg/L
Based on:
DOC
Key result
Parameter:
% degradation (DOC removal)
Value:
88
Sampling time:
28 d
Details on results:
no other details

no overall remarks

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
A 28-d ready biodegradability test (OECD 301E) using sludge from the secondary effluent of a treatment plant indicated that 2-acetylbutyrolactone was ready biodegradable under the conditions of the test (initial concentration 40.2 mg/L DOC). The test substance showed 88% biodegradation after 28 days. The results of the test can be considered reliable without restriction.
Executive summary:

A-Lactone was tested for its ready biodegradability in the modified OECD screening test.

The study procedure was based on OECD guideline No. 301 E, July 17, 1992.

The test piece was added in a quantity of 40.2 mg/l DOC to the test medium.

The inoculum was derived from the secondary effluent of a treatment plant. Anillin was used as reference substance. The observed biodegradability was 88% after 28 days.

The criterion for ready biodegradability (at least 70% removal of DOC in a 10 -day window) was also met in these experiment.

The substance was found to be readily biodegradable.

Endpoint:
biodegradation in water: inherent biodegradability
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Initial conc.:
300 mg/L
Based on:
DOC
Initial conc.:
534 mg/L
Based on:
test mat.
Parameter:
% degradation (DOC removal)
Value:
95
Sampling time:
23 d
Details on results:
The degree of biodegradation for A-Lacton at the end of the test after 23 days is 95%. The plateau-phase is reached after 12
days. The length of the degradation-phase of the reference substance is in the same range as the one of the test substance.

no overall remarks

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
A 28-d inherent biodegradability test (OECD 302B) using a mixture of activated sludge indicated that 2-acetylbutyrolactone showed evidence for ultimate biodegradability under the conditions of the test. The test substance shows 95% biodegradation. The results of the test can be considered reliable without restriction.
Executive summary:

In this report the inherent biodegradability of A-Lacton has been examined using the

modified Zahn-Wellens-Test according to the GLP Standard Operation Procedure

ZWT1991.

A mixture of activated sludge from a domestic sewage works and from a pilot chemical

waste water treatment plant was exposed under controlled conditions to 534 mg/l

A-Lacton (= 300 mg DOC/l). The degradation of the test substance was monitored during

28 days by determination of the DOC values at regular time intervals and expressed as

percentage biodegradation at this time.

A-Lacton shows a biodegradability of 95%. A physico-chemical degradation of 32% was

observed when the test substance was incubated without inoculum.

Thus, A-Lacton may be characterized as: evidence for ultimate biodegradability

Description of key information

One study is included in this dossier and regarded as a key study (Klimisch score of 1). The biodegradability of 2 -acetylbutyrolactone was determined according to OECD Guideline 301E. Under the conditions of the test, 2 -acetylbutyrolactone was determined to be readily biodegradable within 28 days.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

not required - both tests indicate that A-Lactone is readily biodegradable