Ethyl octanoate

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:

2002-01-29 to 2002-01-31

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:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

1992

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

DOC was measured in all concentration levels and control at test start (0 h, fresh media) and test end (48 h, old media).

Details on test solutions:

- Stock solution: 100 mg/L was prepared with dilution water one day prior to application
- Dispersion treatment: 24 h an a magnetic stirrer, afterwards filtration with 0.45 µm
- Test dilutions: 1:16-1:8-1:4 -1:2-1:1
- Real test concentrations: 0.6 - 1.1 -2.5-4.8 - 9.3 mg/L

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna STRAUS
- Source: Institut für Wasser-, Boden- und Lufthygiene des Bundes- gesundheitsamtes, Corrensplatz, D-14195 Berlin
- Feeding: 5 x weekly ad libitum with a mix of Scenedesmus subspicatus and Chlorella vulgaris, with an algae cell density of > 106cells/mL
- Culture medium: Elendt M4, according to Elendt (1990), modified to a total hardness of 160 to 180 mg CaCO3/L
- Culture: In 2-3 L glass vessels with approximatively 1.8 L culture medium, at 21 °C, in an incubator, 16 h illumination, illumination strength max. 20 µmol-m-2.s-1.
- Age: less than 24h old
- Acclimation: 2h in dilution water

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

265 mg/L

Test temperature:

18 - 22 +/- 1 °C

pH:

7.72

Dissolved oxygen:

8.62 mg/L O2

Nominal and measured concentrations:

Measured concentrations (Based on DOC analysis): 0, 0.6, 1.1, 2.5, 4.8 and 9.3 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (5 cm ID x 8 cm H), 50 mL
- Volume study medium: 20 mL
- Number of study organisms per concentration and control: 20 animals
- Number of animals per test vessel: 5
- Number of parallel samples per concentration: 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: According to EEC 92/69 L383A C.2
- Culture medium different from test medium: no
- Intervals of water quality measurement: 0 h; 48 h (pH, dissolved oxygen); temperature permanently

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light / 8 hours dark
- Illumination: Diffuse light, illumination strength max. 20 µmol-m-2 (corresponding to 1200 lx)

TEST CONCENTRATIONS
- Test concentration: 5 dilutions: 0.6 - 1.1 -2.5-4.8 - 9.3 mg/L

CONTROL
- dilution water

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

5.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: DOC concentrations

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

7.9 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: DOC concentrations

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 9.3 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: DOC concentrations

Basis for effect:

mobility

Details on results:

The test item was clearly dissolved in all concentration levels throughout exposure.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels after 24h: EC 50 = 2.0 mg/L (CL 1.9 - 2.1 mg/L), EC 10 = 1.7 mg/L
The result is within the prescribed concentration range.

Range finding test results

Mean immobilisation rates (%) after 24 and 48h:

Dilution	24h	48h
1:1	95	100
1:10	0	0
1:100	0	0
Control	0	0

Results of the main test

Mean immobilisation rates (%) after 24 and 48h:

Concentration (mg/L)	24h	48h
9.3	65	70
4.8	0	0
2.5	0	0
1.1	0	0
0.60	0	0
Control	0	0

DOC - Analysis of New (Oh) and OId Media (48h)

Dilution	DOC (mg/L)				ThTOC (mg/L)	Recovery rate (%)	Real concentration (mg/L)
	0 h	48 h	mean	Corrected against DOC control
1:1	11.33	9.44	10.39	6.48	69.71	9.3	9.3
1:2	7.44	7.11	7.28	3.37	34.86	9.7	4.8
1:4	5.64	5.60	5.62	1.71	17.43	9.8	2.5
1:8	4.77	4.59	4.68	0.77	8.71	8.8	1.1
1:16	4.29	4.38	4.34	0.43	4.36	9.9	0.6
Control	4.22	3.59	3.91	---	---	---	---

Validity criteria fulfilled:

yes

Conclusions:

The EC50 (48h) was determined to be 7.9 mg/L, the EC10 (48h) was 5.4 mg/L and the EC100 (48h) > 9.3 mg/L.

Executive summary:

In the current study the acute immobilisation (EC50) of the test item to Daphnia magna (Straus) was determined according to OECD guideline 202.

The study was conducted under static conditions over a duration of 48 hours. 20 test organisms were exposed to each test concentration and control.
 The real test concentrations were calculated based an the DOC-analysis of the test item dilutions alter 0 and 48 h (mean values of DOC measurments): 0.6, 1.1, 2.5, 4.8 and 9.3 mg/L

The test item was clearly dissolved in all concentration levels throughout exposure. The 24 h and 48 h EC10 and EC50 values were calculated by probit analysis in the tested concentration range.

 

The EC50 (48h) was determined to be 7.9 mg/L, the EC10 (48h) was 5.4 mg/L and the EC100 (48h) > 9.3 mg/L.

 

Description of key information

EC50 (48 h) = 7.9 mg/L (Daphnia magna, OECD 202)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

7.9 mg/L

Additional information

One experimental study is available investigating the short-term effects of the substance to aquatic invertebrates. The study was performed according to OECD 202 (GLP) with the water flea Daphnia magna. Measured concentrations of 0.6, 1.1, 2.5, 4.8 and 9.3 mg/L were tested under static conditions. Test concentrations were verified by DOC-analysis at the beginning and end of the exposure period. Immobilisation of D. magna was observed after 48 h resulting in an EC50 (48 h) of 7.9 mg/L based on the arithmetic mean measured concentrations.