Methyl (S)-(-)-lactate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

Serious reporting deficiencies, both in terms of methods and results (e.g., inoculum, blanks, replicates, test conditions not reported); spacing of sampling times unsuitable for determining ready biodegradability (BOD determination only after 5 and 28 days); see further below for details.

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.5 (Degradation: Biochemical Oxygen Demand)

Deviations:

not specified

Remarks:

It is furthermore not clear which method was used for the test substance (EU C.5 or OECD 301D).

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

yes

Remarks:

Sampling only on day 5 and 28; no inoculum blank, abiotic control, toxicity control, replication and corresponding variability reported; no information on primary analytical parameter; no information on inoculum and test conditions.

GLP compliance:

not specified

Oxygen conditions:

not specified

Inoculum or test system:

not specified

Details on inoculum:

No data

Duration of test (contact time):

ca. 28 d

Initial conc.:

2.04 mg/L

Based on:

test mat.

Initial conc.:

ca. 1.38 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation:

other: BOD (biochemical oxygen demand)

Details on study design:

No data

Reference substance:

acetic acid, sodium salt

Reference substance:

other: mixture of glucose and glutamic acid, depending on the guideline used (not differentiated among a series of lactate esters)

Parameter:

other: % degradation based on BOD

Value:

ca. 15

Sampling time:

5 d

Key result

Parameter:

other: % degradation based on BOD

Value:

ca. 76

Sampling time:

28 d

Parameter:

BOD5

Value:

>= 0.21 - <= 1.05 g O2/g test mat.

Results with reference substance:

Complete degradation within five days.

Validity criteria fulfilled:

no

Remarks:

Reporting insufficient for evaluating validity.

Interpretation of results:

readily biodegradable

Remarks:

Data insufficient for definitive evaluation of biodegradability.

Conclusions:

The substance is biodegradable within the 28-d test period. However, due to considerable reporting deficiencies, a final conclusion on biodegradability is not possible (10-d window not evaluable).

Executive summary:

Several esters of lactic acid were tested for ready biodegradability and/or biochemical oxygen demand according to OECD 301D (closed bottle test), however with significant methodological and reporting deficiencies. Alloction of test methods to substance is neither evident from the materials and methods section nor from the results section.Therefore, study performance and documentation are considered unreliable. Nevertheless, the results indicate that methyl (S)-lactate may be readily biodegradable, but data allowing evaluation of the 10-d window are missing.

 

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

Validated QSAR model, acceptable in a regulatory context.

Justification for type of information:

QSAR prediction

1. SOFTWARE
EpiSuite 4.11

2. MODEL (incl. version number)
BIOWIN v4.11

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES: OC(C)C(=O)OC

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF.

5. APPLICABILITY DOMAIN
See attached QMRF.

6. ADEQUACY OF THE RESULT
Ready biodegradability is a key parameter for the environmental risk assessment and for classification for environmental hazards.

Qualifier:

according to guideline

Guideline:

other: REACH guidance on information requirements and chemical safety assessment, chapter R.6: QSARs and grouping of chemicals, May 2008.

Principles of method if other than guideline:

(Q)SAR calculation

GLP compliance:

no

Key result

Parameter:

probability of ready biodegradability (QSAR/QSPR)

Remarks on result:

readily biodegradable based on QSAR/QSPR prediction

Details on results:

Biowin1 (Linear Biodeg Probability) 1.0309
Biowin2 (Non-Linear Biodeg Probability) 0.9988
A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast
A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

Biowin3 (Survey Model - Ultimate Biodeg) 3.2693
Biowin4 (Survey Model - Primary Biodeg) 4.0559
Result Classification: 5.00 -> hours 4.00 -> days 3.00 -> weeks
(Primary & Ultimate) 2.00 -> months 1.00 -> longer

Biowin5 (MITI Linear Biodeg Probability) 0.7730
Biowin6 (MITI Non-Linear Biodeg Probability) 0.9115
A Probability Greater Than or Equal to 0.5 indicates --> Readily Degradable
A Probability Less Than 0.5 indicates --> NOT Readily Degradable

Biowin7 (Anaerobic Linear Biodeg Prob) 0.8157
A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast
A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

The prediction is not dependent on stereochemistry.

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Conclusions:

Methyl (S)-lactate is predicted to be readily biodegradable by the (Q)SAR model BIOWIN v4.11.

Executive summary:

Methyl (S)-lactate is predicted to be readily biodegradable by the (Q)SAR model BIOWIN v4.11.

Description of key information

Methyl (S)-lactate is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

According to QSAR modelling, the substance is readily biodegradable. This was also shown in an experimental study from Bowmer (1998), though having deficiencies regarding reporting.