Ethyl (S)-2-hydroxypropionate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-08-08 to 1992-04-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

- ethyl S(-) lactate,
- Batch nr.: EK 355.8
- Purity > 97 %

Analytical monitoring:

yes

Details on sampling:

- Concentrations: At t = 0 h samples were taken from the control medium and from the freshly prepared solutions of 100, 320 and 1000 mg/L. At the end of the test samples of the "spent" control medium and the same "spent" solutions were taken.
- Sampling method: Samples of 50 mL were taken in 50 mL glass bottles.
- Sample storage conditions before analysis:samples were immediately transported under cool condition to the Analytical Department of the TNO Institute. Immediately upon arrival the samples were transferred to autosampler vials and analysis was started.

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

The organism used was the fresh-water crustacean Daphnia magna, cultured in the laboratory under standard conditions, according to the principles of NPR 6503. The animals were less than 24 h old at the beginning of the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

220 mg/L

Test temperature:

19.9 °C

pH:

The pH values of the test solutions and control media varied between 7.3 and 8.1.

Dissolved oxygen:

> 7.5 mg/L

Nominal and measured concentrations:

Nominal concentrations: 0, 100, 180, 320, 560, 1000 and 1800 mg/L.
Measured concentrations (for nominal concentrations 0, 100, 320 and 1000 mg/L), at t = 0: < 1, 84, 277 and 910 mg/L; at t = 48 h: < 1, 50, 240 and 855 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, fill volume: 150 mL all-glass beakers, fill volume 100 mL
- Aeration: none
- Renewal rate of test solution (frequency/flow rate): none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dutch Standard Water (reconstituted water), prepared from Linschoten ground water
- Total organic carbon: 2.0 mg/L
- Metals: Na 1.26 mmol/L, K 0.23 mmol/L, Ca 1.41 mmol/L, Mg 0.78 mmol/L
- Chlorine: 2.81 mmol/L

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 h light, 8 h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): The immobile animals were counted after 24 hours and at the end of the test (48 h) according to the definition given in the OECD guideline no. 202. At the same time the condition (swimming behaviour, colour or any other visual observable morphological or behavioural criterion) of the mobile animals was visually compared with that of the control animals.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

1 078 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CI = 940–1236 mg/L

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

683 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CI = 592–788 mg/L

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

560 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: condition

Details on results:

- Behavioural abnormalities: none
- Observations on body length and weight: not done
- Other biological observations: There were no immobile animals in the control vessels and in the solutions of 320 mg/L and the lower test concentrations (see Table 1). At 560 mg/L, 15 % of the animals died, however, the condition of the surviving animals was equal to that of the control animals (visually assessed) (see Table 2). The NOEC for mobility and condition are therefore 320 and 560 mg/L respectively.
- Mortality of control: no mortality in control
- Other adverse effects control: none
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none
- Effect concentrations exceeding solubility of substance in test medium: none

Table 1.Number of mobile animals (Daphnia magna) at several concentrations of ethyl S(-) lactate and after several exposure times.

Time  (h)	Nominal concentration of test substance (mg/L)
	0	100	180	320	560	1000	1800
0	20	20	20	20	20	20	20
24	20	20	20	20	20	9	3
48	20	20	20	20	17	0	0

 

Table 2.Number of animals (Daphnia magna) and their condition at several concentrations of ethyl S(-) lactate and after several exposure times (a,b,c and d are quadruplicate test vessels)¹⁾.

Time

Nominal concentration of the test substance (mg/L)

(h)

0

100

180

320

a

b

c

d

a

b

c

d

a

b

c

d

a

b

c

d

0

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

24

5^a)

5^a)

5^a)

5^a)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

48

5^a)

5^a)

5^a)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

5^b)

 

Time

Nominal concentration of the test substance (mg/L)

(h)

560

1000

1800

a

b

c

d

a

b

c

d

a

b

c

d

0

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

5^a)

24

5^b)

5^b)

5^b)

5^b)

4

1

3

1

0

1

1

1

4^f)

1^f)

3^f)

1^f)

5^d)

1^ef)

1^ef)

1^f)

1^d)

4^d)

2^d)

4^d)

0

4^d)

4^d)

4^d)

48

5^b)

4

4

4

0

0

0

0

0

0

0

0

4^b)

4^b)

4^b)

4^d)

1^d)

3^d)

1^d)

1^d)

1^d)

1^d)

1^d)

1^d)

1^d)

 

The following codes are used to denote condition:

a) Condition of all test animals, visually assessed, normal (=good).

b) Condition of all test animals assessed, equal to that of the control animals.

c) The quoted number of animals was immobile.

d) The quoted number of animals was dead.

e) The quoted number of animals was mobile, according to the definition given in OECD Guideline no. 202, but their movements were slower.

f) The quoted number of animals was mobile, but they swam slower with irregular movements.

Validity criteria fulfilled:

yes

Conclusions:

The 48-h EC50 (immobilization) of ethyl (S)-lactate to Daphnia magna is 683 mg/L. The 48-h NOEC (immobilization) of ethyl (S)-lactate to Dapnia magna is 320 mg/L.

Executive summary:

The acute toxicity of ethyl (S)-lactate to the freshwater crustacean Daphnia magna was determined as decribed in OECD guideline no. 202 and according to the OECD principles of Good Laboratory Practice. The test was carried out with 4 × 5 daphnias (quadruplicate test solutions) for each concentration, and the test solutions were not replaced. The exposure duration was 48 hours. The nominal concentrations tested were 100, 180, 320, 560, 1000 and 1800 mg/L. At the start of the test the testsubstance appeared to be completely dissolved at all concentrations tested (visually assessed). The actual concentrations of ethyl (S)-lactate in the freshly prepared test solutions were determined with gas chromatography (direct injection). They were between 84 and 91 % of the nominal concentrations just after dosing (average 87 %). To test the stability of the test substance concentrations of ethyl (S)-lactate were also analysed at the end of the test and appeared to be between 50 and 86 % of the nominal concentration (average 70 %).

The results of the test were (as nominal concentrations):

24-h EC50 (mobility): 1078 mg/L

48-h EC50 (mobility): 683 mg/L

Slope of the concentration-effect curve: 6.0

48-h EC100 (mobility): 1000 mg/L

48-h NOEC (mobility = 48-h ECO): 320 mg/L

48-h NOEC (condition): 560 mg/L

Description of key information

The 48-h EC50 (immobilization) reported for Ethyl (S)-lactate to Daphnia magna was 683 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

ca. 683 mg/L

Additional information

No adverse effects have been observed at the highest recommended concentration (100 mg/L). Accordingly, the substance is not hazardous in terms of the CLP Regulation.