2-ethylhexyl nitrate

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:

October 2021

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)

Version / remarks:

Adopted 13. Apr. 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Batch number of test material: 123L21
- Purity: > 99.5 %

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Closed vessel at room temperature (20 ± 5 °C), dry, in the dark
- Stability and homogeneity of the test material in the vehicle/solvent under test conditions (e.g. in the exposure medium) and during storage: Homogeneous and stable under storage conditions

Analytical monitoring:

yes

Details on sampling:

At the beginning and at the end of the test, the content of the test item in the test solutions was determined using GC-MS -determination.

At the end of the test, the measured concentrations were much lower than at the beginning. Although the test was performed in completely filled and closed test vessels, it is highly probable that some of the test substance was removed by volatilisation during handling. Because the measured concentrations were not within the range of 20 % of the nominal concentration, the determination of the results was based on the geometric mean of the measured concentrations. Analytical data are provided in Tables 1, 2 and 3.

Vehicle:

no

Details on test solutions:

Test solution was prepared in accordance with OECD Guidance Document No. 23, Second Edition, Guidance Document on Aqueous-phase Toxicity Testing of Difficult Test Chemicals, adopted 08. Feb. 2019. the test medium (M4 media) was deionised water with an enrichment of certain minerals was used in the test. The minerals which are added comply to the composition M4 (see Table 4) derived by ELENDT as stated in the OECD-Guideline. A saturated solution was prepared for the test. This was done by pipetting the real load of 100.0 mg/L corresponding to a volume of 104 µL/L test item (based on a density of 0.962 g/mL), onto the surface of the corresponding amount of M4-medium and stirring vigorously for 23 hours. After a settling time of 1 hour, the first 50 mL of the lower phase were discarded. The solution was used as highest test concentration and also for preparation of the lower concentrated treatments (4.6 / 10 / 22 and 46 mg/L), by dilution with M4-medium.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna Straus
- Strain/clone: Berlin
- Age at study initiation (mean and range, SD): 0-24 hours
- Method of breeding: Daphnia magna is bred in the LAUS GmbH throughout the year. The animals are kept for the use in toxicity tests. They multiply by parthenogenesis, thus being genetically identical.

21 hours before the start of the test, the adult animals were separated from the young. 0.5 hours before test start, the adults were caught with the help of a glass tube, and the new-born daphnia (age < 24h) were sieved from the medium and immediately placed into a beaker containing M4-medium. After the settling-in period, animals which showed no apparent damage were used for the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

As per OECD 202 guideline

Hardness:

Not reported

Test temperature:

19.0 – 20.5 °C

pH:

See Table 5

Dissolved oxygen:

See Table 5

Salinity:

N/A

Conductivity:

Not reported

Nominal and measured concentrations:

4.6 / 10 / 22 / 46 / 100 mg/L nominal concentration. Concentrations were determined based on the result of a non-GLP pre-test.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass flask
- Type: Closed
- Material, size, headspace, fill volume: Glass flask, nomnal volume 65 mL, completely filled with test solution
- Volume of solution: 65 mL
- No. of organisms per vessel: Five
- No. of vessels per concentration (replicates): Four
- No. of vessels per control (replicates): Four

OTHER TEST CONDITIONS
- Photoperiod: 16/8 hours, using LEDs

EFFECT PARAMETERS MEASURED: Immobilisation

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (CAS No. 7778-50-9)

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.83 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Additional details are reported in the section 'Any other information on results incl. tables'.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: 24-hour EC50
- EC50: 1.20-2.82 mg/L

Reported statistics and error estimates:

95% confidence interval: 0.67-1.04 mg/L.

Table 6: Immobility data

Nominal Concentration in mg/L	Immobility 24 hours					Immobility 48 hours
	absolute				in %	absolute				in %
Blank control	0	0	0	0	0	0	0	0	0	0
4.6	0	0	0	0	0	0	0	0	0	0
10	0	1	0	0	5	0	1	0	1	10
22	0	0	0	0	0	1	2	2	3	40
46	4	3	1	3	55	5	4	4	5	90
100	3	5	4	4	80	5	5	5	5	100

Validity criteria fulfilled:

yes

Conclusions:

In a short-term toxicity study in aquatic invertebrates conducted according to OECD 202, a 48 -hour EC50 of 0.83 mg/L (95% confidence interval 0.67 -1.04 mg/L) was determined in Daphnia magna. All validity criteria were met and the study was considered Klimisch Code 1 (reliable without restriction).

Executive summary:

A short-term toxicity study was conducted in Daphnia magna according to OECD guideline 202. Test solution was prepared in accordance with OECD Guidance Document No. 23, Second Edition

, Guidance Document on Aqueous-phase Toxicity Testing of Difficult Test Chemicals, adopted 08. Feb. 2019. The test medium (M4 media) was deionised water with an enrichment of minerals which are added comply to the composition M4 (see Table 4) derived by ELENDT as stated in the OECD-Guideline.

A saturated solution was prepared for the test. This was done by pipetting the real load of 100.0 mg/L corresponding to a volume of 104 µL/L test item (based on a density of 0.962 g/mL), onto the surface of the corresponding amount of M4 -medium and stirring vigorously for 23 hours. After a settling time of 1 hour, the first 50 mL of the lower phase were discarded. The solution was used as highest test concentration and also for preparation of the lower concentrated treatments (4.6 / 10 / 22 and 46 mg/L), by dilution with M4 -medium. Concentrations were determined based on the result of a non-GLP pre-test.

At the beginning and at the end of the test, the content of the test item in the test solutions was determined using GC-MS -determination. At the end of the test, the measured concentrations were much lower than at the beginning. Although the test was performed in completely filled and closed test vessels, it is highly probable that some of the test substance was removed by volatilisation during handling. Because the measured concentrations were not within the range of 20 % of the nominal concentration, the determination of the results was based on the geometric mean of the measured concentrations

A 48 -hour EC50 of 0.83 mg/L (95% confidence interval 0.67 -1.04 mg/L) was determined in Daphnia magna. All validity criteria were met and the study was considered Klimisch Code 1 (reliable without restriction).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

0.83 mg/L