2-methylpropyl-(R)-2-hydroxypropanoate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study results published were generated according to OECD guideline 202 " Daphnia sp., Acute Immobilisation Test and Reproduction Test” and in compliance with GLP. The test substance is isobutyl-(S)-lactate, which is used for read-across. Since the test substance is the optical antipode of the target compound isobutyl-(R)-lactate and results for short-term toxicity in invertebrates can be extrapolated, read-across is fully justified.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

other: EPA Guideline No. EG-1 and Technical Support Document No. ES-1 (1982)

Deviations:

not specified

GLP compliance:

yes

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea

Test type:

static

Water media type:

not specified

Limit test:

no

Total exposure duration:

48 h

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

395 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CI = 355-438 mg/L

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

180 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48

Dose descriptor:

other: NEC

Effect conc.:

307 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CI = 276-321 mg/L

Validity criteria fulfilled:

not specified

Conclusions:

The experiment was conducted in accordance with OECD guideline 202 and revealed an 48–hour EC50 of 395 mg/L (nominal). The 48–hr NOEC based on immobilisation was 180 mg/L.

Executive summary:

The 48-hr acute toxicity of isobutyl-S-lactate to Daphnia magna was studied under static conditions. Daphnids were exposed to control and test chemical at nominal concentrations that are not further specified for 48 hr. Immobilisation and sublethal effects were observed test termination. The 48-hour LC₅₀/EC₅₀was 395 mg/L. The 48-hr NOEC based on immobilization was 180 mg/L.

Based on the results of this study and read across from isobutyl-S-lactate its optical antipode isobutyl-R-lactate would not be classified as toxic to aquatic organisms in accordance with the CLP Regulation.

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates, despite some reporting deficiencies.

Results synopsis

Test organism age: Neonates

Test type: Static

EC₅₀: 395 mg/L (95 % CI = 355–438 mg/L

NOEC: 180 mg/L

Endpoint(s) effected: Immobilisation

Description of key information

The short-term toxicity test with Daphnia magna revealed a 48-h EC₅₀ of 395 mg/L (nominal). The 48-h NOEC was 180 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

395 mg/L

Additional information

The short-term toxicity of isobutyl-(S)-lactate to aquatic invertebrates was studied in a 48-h test under static conditions according to the OECD guideline 202, using Daphnia magna as test organism. Based on the observations of mortality and immobilisation, the 48-h EC₅₀ was 395 mg/L (nominal concentration). The 48-h NOEC was 180 mg/L. Although the average measured concentrations of the test substance in the media at the beginning and in the end of the experiment only accounted for 70 to 80 % of the applied nominal concentration, the threshold for acute effects (EC₅₀ > 1 mg/L) is clearly exceeded. This result can be extrapolated to the target substance isobutyl-(R)-lactate without restrictions, since being the optical antipode of the test substance isobutyl-(S)-lactate.