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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28 days
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:
Published research covering the biodegradability of alkyl lactates and lactic acid.
The research concludes that the rate of biodegradation is closely corrolated to partition coeficient with higher water solublity leading to more rapid biodegradation.
Considered reliable research covering any type of lactate.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1998

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Principles of method if other than guideline:
Different methods were used, but those relating to oxygen consumption were reported (Closed Bottle and Manometric methds)
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Lactic acid
EC Number:
200-018-0
EC Name:
Lactic acid
Cas Number:
50-21-5
Molecular formula:
C3H6O3
IUPAC Name:
2-Hydroxypropanoic acid

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Inoculum was prepared from activated sludge originating from domestic sewage.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
ca. 3 mg/L
Based on:
ThOD
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (DOC removal)
Value:
ca. 50
Sampling time:
5 d
Parameter:
% degradation (DOC removal)
Value:
ca. 67
Sampling time:
28 d
Details on results:
Only 2 time points reported.
All water soluble lactates resulted in rapid biodegradation, mostly exceeding 60% after 28 days

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Remarks:
Details of controls were not included
Interpretation of results:
readily biodegradable, but failing 10-day window
Conclusions:
Lactic acid and lactate salts are major metabolites found in living cells. Lactates are readily consumed in foods (milk).
Rapid biodegradation was expected.