Ethyl 2-methylbutyrate

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:

15 August to 17 August 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/l
- Sampling method: Samples taken in bottles at 0 and 48h.
- Sample storage conditions before analysis: No data

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 100 mg of EMB was dissolved in 1l of water.
- Control: Yes

Test organisms (species):

Daphnia magna

Details on test organisms:

- Common name: Daphnia magna STRAUS, parthenogenetic females
- Source: Strain of Bundesgesundheitsamt Berlin
- A population of parthenogenetic females of synchronized age structure is maintained since more than 15 years in the test facility under constant temperature conditions (20 +/- 1°C) at a 16:8 hour light-dark photoperiod (illumination: < 1000 lux).
- The culture water (so-called ‘M4 medium’) is partly renewed once a week.
- The Daphnia are exclusively fed with unicellular green algae (Scenedesmus subspicatus CHODAT) ‘ad libitum’.
- Mortalities of parent Daphnia during the culture period are recorded daily in a semi-quantitative way. The neonates are separated from their parent Daphnia by filtration prior to the acute test.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

Observations were made on the swimming ability and the immobilisation rate, respectively, after 24 and 48 hours of exposure.

Hardness:

The total hardness of the dilution water, measured at test start, was 14.9°dH (266 mg/l CaCO3).

Test temperature:

- Control (48h): 20°C
- Test concentration (100 mg/l) (48h): 20.1°C

pH:

- Control (48h): 7.8
- Test concentration (100 mg/l) (48h): 7.7

Dissolved oxygen:

- Control (48h): 8.8 mg/l and 99.5% saturation
- Test concentration (100 mg/l) (48h): 7.0 mg/l and 79.3% saturation

Salinity:

No data

Nominal and measured concentrations:

Test concentration/s (nominal): 100 mg/l

Pre-treatment of the test substance: 100 mg of the test substance were directly added to 1 litre of dilution water to produce the only test concentration.

Details on test conditions:

TEST SYSTEM
- Test vessel: Karlsruher Flaschen holding 10 neonates in 250-300 ml of test medium
- Type (delete if not applicable): closed-bottle conditions
- Aeration: none
- 1 test concentration plus 1 control
- No feeding during the exposure period
- No. of organisms per vessel: 10 neonates per vessel
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- Method of initiation: neonates were placed in prepared media
- Method of administration: stock solution
- Medium renewal: none
- Criteria of effects: The criterion of adverse effects used in this study was the substance-induced alteration of the normal mobility behaviour and the loss of locomotory actions of the neonates, observed at 24 and 48 hours.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Culture and dilution water - Reconstituted water (so-called ‘M4 medium’, originally described in Water Research 24 (9): 1157-1167), prepared according to the recommendations of Bundesgesundheitsamt Berlin. This standard dilution water is used for both, the stock and test solutions of the maintenance of the test animals and the preparation of test substance.

The total hardness of the dilution water, measured at test start, was 14.9°dH (266 mg/l CaCO3).

OTHER TEST CONDITIONS
- Photoperiod: 16 h light:8 h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): EC0 (24h and 48h)

TEST CONCENTRATIONS
- Test concentrations (nominal): 100 mg/l
- Range finding study: Deviating from the above test guideline and considering the decrease of the test concentrations during the preliminary test, the main test was conducted under closed-bottle conditions in so-called ‘’Karlsruher Flaschen”.

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

>= 61.6 mg/L

Nominal / measured:

meas. (not specified)

Remarks on result:

other: mean measured

Details on results:

24h EC0: The results are expressed in terms of nominal concentrations (at 24h), and in terms of mean measured concentrations (at 48h). Measured concentrations correspond to 73.6% of nominal values at 0 hours, and to 49.6% of nominal values at 48 hours, respectively.

48h EC0: The results are expressed in terms of nominal concentrations (at 24h), and in terms of mean measured concentrations (at 48h). Measured concentrations correspond to 73.6% of nominal values at 0 hours, and to 49.6% of nominal values at 48 hours, respectively.

Results with reference substance (positive control):

No data

Reported statistics and error estimates:

No data

N/A

Validity criteria fulfilled:

yes

Conclusions:

Analysis of the immobilisation rates give the following results:

Time [h] EC 0 [mg/l]
24 ≥ 100 mg/I
48 ≥ 61.6 mg/I

The results are expressed in terms of nominal concentrations (at 24h), and in terms of mean measured concentrations (at 48h).

Measured concentrations correspond to 73.6% of nominal values at 0 hours, and to 49.6% of nominal values at 48 hours, respectively.

Executive summary:

A study was performed to assess the acute toxicity of Ethyl Methylbutyrate-2 to Daphnia magna STRAUS under static conditions in a closed bottle system.

The study was conducted in accordance with EEC Methods for Determination of Ecotoxicity Annex to Directive 92/69/EEC (O.J. No. L383A, 29.12.92) Part C, Method 2 ‘Acute toxicity for Daphnia’ which is in most parts equivalent to the OECD Guideline for Testing of Chemicals No. 202 ‘Daphnia sp., Acute Immobilisation Test and Reproduction Test, Part I - The 24h EC_5O Acute Immobilisation Test’.

 

The Daphnia were exposed to a limit test concentration of nominally 100 mg/l of Ethyl Methylbutyrate-2 dissolved in water. Observations were made on the swimming ability and the immobilisation rate, respectively, after 24 and 48 hours of exposure. The following values were determined:

 

Time [h]  EC 0 [mg/l]

    24       ≥ 100 mg/l

    48       ≥ 61.6 mg/l

 

The results are expressed in terms of nominal concentrations (at 24h), and in terms of mean measured concentrations (at 48h). Measured concentrations correspond to 73.6% of nominal values at 0 hours, and to 49.6% of nominal values at 48 hours, respectively.

 

Description of key information

EC0 was determined as > 61.6 mg/L hence the EC/LC50 value has been taken to be the same value.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

61.6 mg/L

Additional information

Time [h]  EC 0 [mg/l]

    24       ≥ 100 mg/l

    48       ≥ 61.6 mg/l

 

The results are expressed in terms of nominal concentrations (at 24h), and in terms of mean measured concentrations (at 48h). Measured concentrations correspond to 73.6% of nominal values at 0 hours, and to 49.6% of nominal values at 48 hours, respectively.

In order to assign a value to the EC/LC50 the EC0 has been used.