Methyl (S)-(-)-lactate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Justification for type of information:

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

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2 200 mg/L

95% CI:

>= 1 900 - <= 2 600

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2 300 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control: yes
- Observation of abnormalities: no
- Unusual cell shape: no
- Colour differences: no
- Flocculation: no
- Adherence to test vessels: no
- Aggregation of algal cells: no
- Other: Many bacteria were found in the cultures containing test substance at the end of the test.
- Any stimulation of growth found in any treatment: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no

Table1: Measured concentrations of ethyl (S)-lactate.

Nominal concentration [mg/L]	Measured concentrations
	start		end
	mg/L	% of nominal	mg/L	% of nominal
0	<1		<1
100	110	110	54	54
1000	870	87	850	85
3200	2970	93	3040	95
Average % of nominal concentration	97		78

 

Table 2: Set of cell counts (1.0E+04 particles/mL, corrected for background) 

Time [h]	Nominal concentration [g/L]
	0	0	0.10	0.32	0.58	1.0	1.8	3.2
0	0.9	1.0	0.9	0.9	1.0	0.9	1.0	1.0
24.5	5.9	5.8	5.7	5.5	4.8	5.1	4.3	3.5
49	34.7	32.4	33.7	32.2	28.2	27.9	21.9	13.3
71.5	191.5	175.7	208.1	230.2	164.0	219.0	183.3	23.4

Executive summary:

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

 

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

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

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

no

Specific details on test material used for the study:

SMILES: C(=O)(C(C)O)OC

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

368 mg/L

Remarks on result:

other: calculated

Validity criteria fulfilled:

yes

Conclusions:

The EC50 for methyl-(S)-lactate was estimated at 368 mg/L, showing low acute toxicity to algae, not fulfilling the CLP criterion for being classified as environmentally hazardous (≤100 mg/L).

Executive summary:

For the determination of the acute toxicity to algae value the 'Leadscope Enterprise model for acute toxicity to microalgae (72 h growth inhibition, EC50)' as included in the Danish QSAR Database, has been applied. Based on the calculated 72-h EC50 value of 368 mg/L it can be concluded that methyl-(S)-lactate shows low acute toxicity to algae, not fulfilling the CLP criterion for being classified as environmentally hazardous (≤100 mg/L).

Description of key information

The modelled EC50 value of methyl (S)-lactate is 368 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

368 mg/L

Additional information

The EC50 value for the read-across substance ethyl-(S)-lactate is 2200 mg/L based on inhibition of the algal growth rate. Thus, the substance of scope is practically non-toxic to algae. Both the predicted (368 mg/L) and the experimental value are significantly higher than 100 mg/L, the effect concentration that would trigger classification under CLP.