Propanoic acid, 2-hydroxy-, ammonium salt (1:1), (2S)-

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

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) 0.9361
Biowin2 (Non-Linear Biodeg Probability) 0.9704
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) 3.5247
Biowin4 (Survey Model - Primary Biodeg) 4.2328
Result Classification: 5.00 -> hours 4.00 -> days 3.00 -> weeks
(Primary & Ultimate) 2.00 -> months 1.00 -> longer

Biowin5 (MITI Linear Biodeg Probability) 0.7362
Biowin6 (MITI Non-Linear Biodeg Probability) 0.8791
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) 0.9102
A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast
A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Conclusions:

L-(+)-lactic acid is predicted to be readily biodegradable by the (Q)SAR model BIOWIN v4.10.

Executive summary:

L-(+)-lactic acid is predicted to be readily biodegradable by the (Q)SAR model BIOWIN v4.10.

This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Justification for type of information:

For details and justification of read-across please refer to the attached report in section 13 of IUCLID.

Reason / purpose for cross-reference:

read-across source

Test performance:

The oxygen concentrations measured in the various bottles of the BOD determination are given in Annex B and discussed in detail in sections 3.1 and 3.2. Table 1 lists the mean oxygen concentrations measured and the oxygen consumption and BOD values calculated for L(+) lactic acid (referring to the test substance as such, containing 80 % L-(+)-lactic acid).
The pH of the medium in the BOD bottles was 7.0-7.1 at the start of the test, 6.6-6.9 after twenty days. The pH values in bottles with glucose added were generally lower 6.1-6.3. The temperatures measured in the BOD bottles varied between 19.9 and 20.7 °C.

Parameter:

% degradation (O2 consumption)

Value:

50

Sampling time:

5 d

Parameter:

% degradation (O2 consumption)

Value:

67

Sampling time:

20 d

Details on results:

The BOD5 and BOD20 values of the various concentrations of L-(+)-lactic acid were in the ranges 0.44-0.45 mg O2/L and 0.54-0.60 mg O2/L, respectively; it was therefore concluded that the BOD5 and BOD20 of L-(+)-lactic acid are 0.45 and 0.60 mg O2/mg, respectively.
Similar oxygen consumption by the test substance was also found in the presence of glucose and glutamic acid, confirming these results. The COD value of L-(+)-lactic acid was found to be 0.902 mg O2/mg (duplicate values: 0.873 and 0.930 mg O2/mg). The theoretical oxygen demand was calculated tobe 0.85 mg O2/mg.
Comparison of the BOD and COD values indicates that degradation was about 50 % after 5 days and about 67 % after 20 days.

Parameter:

BOD5

Value:

0.45 g O2/g test mat.

Parameter:

COD

Value:

0.9 g O2/g test mat.

Parameter:

BOD5*100/COD

Value:

50

Results with reference substance:

The BOD5 and BOD20 values of the glucose/glutamic acid control were 3.02 mg O2/L and 7.29 mg O2/L respectively; these values indicate that the activity of the inoculum was not quite sufficient. According to ref. (3) a 150 mg/L glucose/glutamic acid mixture should have a BOD5 value of 200 ± 37 mg O2/L; this corresponds to a value of 4.0 ± 0.75 mg O2/L for a 3 mg/L mixture. Since the BOD values were similar at both test substance concentrations and only slightly lower than the value found in the presence of glucose/glutamic acid with its higher microbial activity, the test was regarded as valid.
The results obtained by adding allylthiourea showed that some nitrification had taken place.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

With a BOD5 of 50 % and BOD20 of 67 % of COD, and considering the function of lactic acid in biological systems, it can be concluded that lactic acid is readily biodegradable. Since following an outdated and not fully adequate test guideline, the study is used as supportive data.

Executive summary:

BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) determinations were carried out for L(+)-lactic acid using the method described in the Dutch guidelines “Water – Determination of Biochemical Oxygen Demand after n days (BODn)' (NEN 6634)” and “Water – Determination of Chemical Oxygen Demand (COD)' (NEN 6633)”, respectively. These methods are similar to those referred to in the EC test guidelines C.5 and C.6 (Regulation (EC) No 440/2008). The study was carried out in accordance with the OECD principles of Good Laboratory Practice.

The test substance was a pure chemical with a high solubility in water. Two concentrations (2 and 4 mg/L) were tested. An inoculum was prepared from activated sludge. Its microbial activity appeared to be sufficient although the control substances glucose and glutamic acid had a BOD5 of slightly less than the required value of 4.00 ± 0.75 mg O₂/L.

No toxic effects were found.

The BOD5 of L(+)-lactic acid was 0.45 mg O₂/mg and the BOD20 was 0.60 mg O₂/mg; the COD was 0.90 mg O₂/mg. These figures indicate a degradation of 50 and 67 % after 5 and 20 days, respectively.

This information is used in a read-across approach in the assessment of the target substance.

For details and justification of read-across please refer to the attached report in section 13 of IUCLID.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Description of key information

To evaluate the biodegradability of ammonium-S-lactate read-across from L-(+)-lactic acid is performed. A study report from Hanstveit (1993) does not meet the formal requirements for deriving a "ready biodegradability" classification but is more than sufficient to at least support a classification of "readily biodegradable, not satisfying the 10 day window requirement". The (Q)SAR model BIOWIN v4.10 predicts L-(+)-lactic acid to be readily biodegradable with high reliability. The ammonium compound of ammonium-S-lactate is an inorganic substance which is part of the global ammonium cycle.

Based on this information, ammonium-S-lactate is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.