3-methylbutyl butyrate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-11-09 to 2015-11-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all
- Sampling method: daily taken from freshly prepared test media and from corresponding aged test media after 24h. The test item concentrations were diluted with fish dilution water with the last dilution step in a 20 mL headspace vial containing approx. 1 g sodium chloride. 100 pL methanol were added to the vials before sealing.
- Sample storage conditions before analysis: Original samples were stored at room temperature before preparation, if necessary. All prepared samples were stored at room temperature (in autosampler) before start of analysis, if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Appropriate volumes of the test item were pipetted into measuring flasks filled with 5000 mL of the dilution water. The test media were stirred on a magnetic stirrer (30 minutes, 1100 rpm, room temperature). This procedure was repeated for each renewal day.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: zebrafish
- Source: single brood stock
- Length at study initiation (length definition, mean, range and SD): mean: 2.34 cm
- Weight at study initiation (mean and range, SD): mean: 0.156 g
- Feeding during test: no

ACCLIMATION
- Acclimation period: at least 12 d
- Acclimation conditions (same as test or not): same
- Type and amount of food: Sera Vipan, 4% of fish body weight per feeding day
- Feeding frequency: 3 times/week (The test fish were not be fed 24 h before test start.)
- Health during acclimation (any mortality observed): no mortality observed

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

64 mg CaCO3/L

Test temperature:

22.1 - 23.2 °C

pH:

7.0 -7.7

Dissolved oxygen:

87 - 100 % saturation

Nominal and measured concentrations:

Nominal: 0 (control), 0.342, 0.751, 1.65, 3.64, 8.00 mg/L
Measured (geometric mean):

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass aquaria of 13 L were used, filled with 5 L of dilution water (dimensions: 25.5/18/28 cm, depth of water: 20 cm)
- Type: semi-static (covered with aluminium foil)
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): daily
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.218 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap water of local origin
- Chlorine: filtered on activated charcoal and aerated for at least 24 hours to remove chlorine
- Hardness: 64 mg CaCO3/L
- pH: 7.0 - 7.7
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 9 hours/day
- Light intensity: mean: 0.81 µmol photons/m²s

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality, visible abnormalities (e.g. loss of equilibrium, swimming behaviour, respiratory function, pigmentation, etc.) after 2, 24, 48, 72 and 96 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2
- Range finding study: yes
- Test concentrations: preliminary test with 0.5 mg/L (43% mortality), first definitive test as limit test with 6.8 mg/L (100% mortality)
- Results used to determine the conditions for the definitive study: yes, full test with 5 test concentrations

Reference substance (positive control):

not required

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

2.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3.47 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CI: 2.20 - 5.46 mg/L

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

5.46 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities:
- Observations on body length and weight:
- Other biological observations: staggering, missing escape reflex and hyperventilation observed in highest test concentration (5.46 mg/L)
- Mortality of control: no
- Other adverse effects control: no

Sublethal observations / clinical signs:

Table 1: Cumulative mortality (%) (n=7)

Geometric mean measured concentration (mg/L)	Cumulative mortality (%) after different exposure periods (hours)
	2	24	48	72	96
5.46	0	0	0	86	100
2.20	0	0	0	0	0
1.12	0	0	0	0	0
0.712	0	0	0	0	0
0.249	0	0	0	0	0
Control	0	0	0	0	0

 

Table 2: Environmental conditions

Exposure time (days)	Geometric mean measured concentration (mg/L)	Mean oxygen saturation (%)	pH value	Temperature (°C)
0	5.46	100	7.69	22.1
	2.20	100	7.69	22.1
	1.12	100	7.68	22.2
	0.712	100	7.67	22.2
	0.249	100	7.61	22.1
	Control	100	7.51	22.1
1	5.46	94.5	7.40	23
	2.20	94	7.37	22.8
	1.12	94	7.37	22.9
	0.712	94.5	7.35	22.9
	0.249	95.5	7.19	22.8
	Control	94.5	7.08	22.8
2	5.46	96.5	7.44	22.9
	2.20	95	7.41	22.9
	1.12	95	7.37	23
	0.712	95.5	7.31	22.9
	0.249	95.5	7.20	23
	Control	94.5	7.06	22.7
3	5.46	95	7.42	23.1
	2.20	95	7.22	23.1
	1.12	96	7.19	23
	0.712	96	7.16	23.1
	0.249	96	7.13	23
	Control	95	7.10	22.9
4	5.46	90	7.36	23.1
	2.20	87	7.35	23.1
	1.12	89	7.33	22.9
	0.712	92	7.30	23
	0.249	91	7.23	23
	Control	87	7.22	22.9

- no measurements due to 100% mortality

 

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of Isoamyl isovalerate on Danio rerio was tested in a GLP study according to OECD 203. The LC50 was determined to be 3.47 mg/L based on mean measured concentrations.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The read across justification is included as attachment to section 13 in the IUCLID dataset.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3.19 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: recalculated value to correct differences in molecular weight between source (MW = 172.270 g/mol) and target (MW = 158.240 g/mol).

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3.47 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Isoamyl Isovalerate (CAS 659-70-1)

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

5.46 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Isoamyl Isovalerate (CAS 659-70-1)

Basis for effect:

mortality (fish)

Conclusions:

The toxicity of Isoamyl butyrate to fish (Danio rerio) was predicted from the source substance Isoamyl isovalerate (CAS no. 659-70-1) (see read across justification). The effect value (mortality; LC50) was predicted to be 3.47 mg/L. The recalculated value to correct differences in molecular weight between source (MW = 172.270 g/mol) and target (MW = 158.240 g/mol) was 3.19 mg/L.

Description of key information

The toxicity of the test item Isoamyl butyrate to fish was predicted from the read-across substance Isoamyl isovalerate (CAS no. 659 -70 -1) (refer to the read-across justification, section 13 in the IUCLID dataset).

Both substances have a similar chemical structure and corresponding physicochemical properties. In addition they show similarity in their environmental fate such as biodegradability and their ecotoxic effects on aquatic organisms. Isoamyl isovalerate is therefore proposed suitable to predict the short-term toxicity to fish of the target substance Isoamyl butyrate.

Key study: The toxicity of the read-across substance (Isoamyl isovalerate) to fish was determined in a reliable GLP study according to OECD 203. The LC50 of 3.47 mg/L was estimated based on geometric mean measured concentrations. The recalculated value to correct differences in molecular weight between source (MW = 172.270 g/mol) and target (MW = 158.240 g/mol) was 3.19 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

3.19 mg/L

Additional information

The toxicity of the read-across substance (Isoamyl isovalerate) to fish was determined in a reliable semi-static test performed according to OECD 203 and GLP. Individuals of Danio rerio were exposed to nominal test concentrations of 0.342, 0.751, 1.65, 3.64 and 8.00 mg/L, equivalent to geometric mean measured concentrations of  0.249, 0.712, 1.12, 2.20 and 5.46 mg/L. The test concentrations were analysed by GC-FID daily. After 96 h 100% mortality was observed at 5.46 mg/L, whereas 0% mortality was recorded at 2.20 mg/L. The LC50 (96 h) was estimated at 3.47 mg/L (geometric mean measured). The recalculated value to correct differences in molecular weight between source (MW = 172.270 g/mol) and target (MW = 158.240 g/mol) was 3.19 mg/L.