2-ethyl-3-methylpyrazine

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:

from 2017-03-14 to 2017-04-28

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

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Duplicate samples were taken at the start and at the end of the test (after 48 hours) from the single test concentration of 100 mg/L and from the control. For the 48-hour stability samples, the contents of the respective replicates were combined prior to sampling.

Vehicle:

no

Details on test solutions:

The test medium was prepared by dissolving 102 μL of test item completely in 1000 mL of test water. This volume is equivalent to the concentration of 100 mg/L, considering the relative density of the test item of 0.9830. The test item was mixed into test water by intensive stirring for 30 minutes at room temperature in the dark. After the dissolving procedure the single test concentration of 100 mg/L was a clear solution. The test medium was prepared just before the introduction of the daphnids.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Straus
- Source: bred in the testing laboratory under temperature and light conditions identical to those of the tests
- Age at the start of the test: 6-24 hours old
- Feeding during test: no

BREEDING
- Type and amount of food: algal suspension of the green algae Desmodesmus subspicatus, or a mixture of this algal suspension and a commercial fish diet (Tetra Min® Hauptfutter)
- Feeding frequency: 3 times a week

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

2.5 mmol/L or 250 mg/L CaCO3

Test temperature:

20 - 21 °C

pH:

7.8 - 8.0

Dissolved oxygen:

8.2 - 8.6 mg/L

Salinity:

NA

Conductivity:

no data

Nominal and measured concentrations:

Nominal concentration: 100 mg/L
Measured concentrations: 102 mg/L (0 h) and 97.6 mg/L (48 h)

Details on test conditions:

TEST SYSTEM
- Test vessel: 60-mL test tubes
- Type: closed with glass stoppers
- Material, size, headspace, fill volume: filled with 50 mL test medium; including a headspace to keep the oxygen concentration sufficionet during the test
- Aeration: no
- 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: ISO test water
- Alkalinity: 0.8 mmol/L
- Ca/mg ratio: 2.0 : 0.5 mmol/L
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16-hour light to 8-hour dark cycle with a 30-minute transition period
- Light intensity: 15 - 17 μmol/m^2/s.

RANGE-FINDING STUDY
- Test concentrations: 0, 1, 10, 100 mg/L

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The measured concentration of the test item in the test medium of the single test concentration of 100 mg/L was 102 and 98 % of nominal value at the start and the end of the test, respectively.
In the control and in the test item concentration of 100 mg/L, no daphnids showed immobilization or other signs of disease or stress (e.g., discoloration or unusual behavior such as trapping at the surface water) during the test period of 48 hours.

Results with reference substance (positive control):

For evaluation of the quality of the daphnia clone and the experimental conditions, potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test in March 2017 (24-hour EC50: 1.2 mg/L) showed that the sensitivity of the test organisms was within the range given by the guideline (24-hour EC50: 0.60-2.1 mg/L).

Validity of the test

The test is considered to be valid, as in the control no daphnids showed immobilization or other signs of disease or stress (e.g., discoloration or unusual behavior such as trapping at the surface water). Furthermore, the dissolved oxygen concentration at the end of the test was ≥3 mg/L in the control and test vessels.

Table 1. Effect of the test item on the Mobility of Daphnia magna

Nominal Test Item Concentration [mg/L]	No. of Daphnids Tested	Immobilized Daphnids after 24 Hours		Immobilized Daphnids after 48 Hours
		No.	[%]	No.	[%]
Control 100	20 20	0 0	0 0	0 0	0 0

 

Table 2. Analytical results for test samples

Sampling Day/ Sample Age [d/h]	Nominal Concentration Of Test Item Cnom[mg/L]	Measured Concentration of Test Item x [mg/L]	Sample Preparation Factor F	Determined Concentration of Test Item c [mg/L]	% of Nominal Concentration[%]
0/0 (fresh)	Control 100	n.d. 50.9	2 2	< LOQ 102	n.a. 102
2/48 (aged)	Control 100	n.d. 48.8	2 2	< LOQ 97.6	n.a. 98

 

Validity criteria fulfilled:

yes

Conclusions:

The test item had no acute toxic effects on Daphnia magna in a static 48-hour test up to the nominal concentration of 100 mg/L under the conditions of the test.

Executive summary:

The acute toxicity of the test item on Daphnia magna was determined in a 48-hour static test according to the OECD Guideline for Testing of Chemicals, No. 202 (2004) and the Commission Regulation (EC) No. 440/2008, Part C.2. A limit test was performed with a nominal concentration of 100 mg/L. Additionally, a control group was tested in parallel.

The measured concentration of the test item in the test medium of the single test concentration of 100 mg/L was 102 and 98 % of nominal value at the start and the end of the test, respectively. The determined 48-hour EC50 was > 100 mg/L.

In conclusion, the test item had no acute toxic effects on Daphnia magna in a 48-hour static test up to the nominal concentration of 100 mg/L.

Description of key information

The test item had no acute toxic effects on Daphnia magna in a static 48-hour test up to the nominal concentration of 100 mg/L under the conditions of the test.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

The acute toxicity of the test item on Daphnia magna was determined in a 48-hour static test according to the OECD Guideline for Testing of Chemicals, No. 202 (2004) and the Commission Regulation (EC) No. 440/2008, Part C.2. A limit test was performed with a nominal concentration of 100 mg/L. Additionally, a control group was tested in parallel.

The measured concentration of the test item in the test medium of the single test concentration of 100 mg/L was 102 and 98 % of nominal value at the start and the end of the test, respectively. The determined 48-hour EC50 was > 100 mg/L.

In conclusion, the test item had no acute toxic effects on Daphnia magna in a 48-hour static test up to the nominal concentration of 100 mg/L.