2-(2-ethoxyethoxy)ethyl acetate

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:

25 Jul - 11 Aug 2012

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)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Water samples were taken from the control and each test group (replicates R1 – R4 pooled) at 0 and 48 hours for quantitative analysis.
- Sample storage conditions before analysis: All 0-Hour samples were stored at approximately -20 °C prior to analysis. Duplicate samples were taken and stored at approximately -20 °C for further analysis if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Range finding study: An amount of test item (100 mg) was dissolved in reconstituted water and the volume adjusted to 1 liter to give the 100 mg/L test concentration from which a series of dilutions was made to give further test concentrations of 10, 1.0 and 0.10 mg/L. Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity. Definitive test: An amount of test item (250 mg) was dissolved in reconstituted water and the volume adjusted to 2.5 liters to give the 100 mg/L test concentration from which a series of dilutions was made to give further test concentrations of 56, 32, 18 and 10 mg/L. Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
- Eluate: no
- Differential loading: yes
- Controls: yes, test medium control

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: in-house laboratory cultures
- Age at study initiation (mean and range, SD): < 24 h
- Method of breeding: Adult Daphnia were maintained in 150 mL glass beakers containing Elendt M7 medium in a temperature controlled room at approximately 20 °C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods. Each culture was fed daily with a mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension. Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.
- Feeding during test: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20 - 22 °C

pH:

7.9 - 8.4

Dissolved oxygen:

8.3 - 9.0 mg/L corresponding to 92 - 101% as a percentage of Air Saturation Value

Nominal and measured concentrations:

nominal: control, 10, 18, 32, 56, 100 mg/L
measured: < LOQ, 9.76, 17.8, 31.4, 57.3, 102 mg/L (0 h); < LOQ, 7.98, 16.0, 28.9, 52.6, 93.4 mg/L (48 h)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): covered to reduce evaporation
- Material, size, headspace, fill volume: glass, 250 mL, headspace: 50 mL, fill volume: 200 mL
- 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: reconstituted water
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light / 8 h dark with 20 minute dawn and sudk transition periods
- Light intensity: 577 - 712 lux

EFFECT PARAMETERS MEASURED: Immobilisation or adverse reactions were recorded at 24 and 48 h after the start of exposure.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study
- Test concentrations: 0.10, 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: No immobilization was observed at the test concentrations of 0.10, 1.0 and 10 mg/L. However, immobilization was observed at 100 mg/L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

56 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

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

Details on results:

- Mortality of control: 0%
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: All test preparations were observed to be clear colorless solutions throughout the duration of the test.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50/LC50: EC50 (48 h): 0.45 mg/L (95% CL: 0.42 - 0.48 mg/L)
- Other: A positive control (Harlan Laboratories Ltd., Study Number: 41203341) used potassium dichromate as the reference item at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L. Exposure conditions for the positive control were similar to those in the definitive test. Analysis of the immobilization data by the geometric mean method at 24 hours and the trimmed Spearman-Karber method (Hamilton et al 1977) at 48 hours based on the nominal test concentrations.

Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to range from 80% to 102% of nominal value and so the results are based on nominal test concentrations only.

Table 1: cumulative immobilization data in the definitive test

Nominal concentration [mg/L]	Cumulative immobilized Daphnia (initial population: 5 per replicate)
	24 h						48 h
	R1	R2	R3	R4	Total	%	R1	R2	R3	R4	Total	%
Control	0	0	0	0	0	0	0	0	0	0	0	0
10	0	0	0	0	0	0	0	0	0	0	0	0
18	0	0	0	0	0	0	0	0	0	0	0	0
32	0	0	0	0	0	0	1	0	0	0	1	5
56	0	0	0	0	0	0	0	0	0	0	0	0
100	0	0	0	0	0	0	0	1	3	1	5	25

A single immobilized daphnid was observed at 32 mg/L after 48 hours exposure. This was considered to be due to natural causes rather than a true toxic effect given that less than 10% immobilization occurred and no effects were observed at the higher concentration of 56 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

The 48 hour EC50 was greater than 100 mg/L and the No Observed Effect Concentration (NOEC) was 56 mg/L.

Executive summary:

The acute toxicity of 2 -(2 -ethoxyeythoxy)ethyl acetate to Daphnia magna has been investigated utilising OECD TG 202.

The 48 hour EC50 was greater than 100 mg/L and the No Observed Effect Concentration (NOEC) was 56 mg/L.

Description of key information

EC50 (48 h) > 100 mg/L for Daphnia magna (OECD 202)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

100 mg/L

Additional information

One study is available investigating the short-term effects of 2-(2-ethoxyethoxy)ethyl acetate (CAS 112-15-2) to aquatic invertebrates (Vryenhoef, 2012). The study was performed according to OECD 202 under GLP conditions with the water flea Daphnia magna. A preliminary range-finding study resulted in immobilization at the highest concentration of 100 mg/L. Thus, the definitive test was conducted with five concentrations up to 100 mg/L. 25% immobilization was recorded after 48 h at the highest concentration of 100 mg/L (nominal). Thus, an EC50 (48 h) > 100 mg/L and a NOEC (48 h) of 56 mg/L resulted. Analytical determination of the test concentrations at 0 and 48 h showed measured concentrations were 80% and 102% of nominal, respectively. Thus, the EC50 and the NOEC were based on the nominal concentration.