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Short-term toxicity to fish

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Reference
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
11 August 1997 - 15 August 1997
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.1 (Acute Toxicity for Fish)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 1000 mg/L (only concentration tested)
- Sampling method: water samples were taken from the middle of the test chamber by pipetting approx. 20 mL into a screw-neck glass bottle at 0, 48, and 96 h.
- 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: the test substance was weighed into a beaker. Water for dilution was added and the mixture homogenized using an Ultra-Turrax and poored into the chamber under stirring with a glas rod. After adding the substance, the pH fell to avalue of 4.0. It was then adjusted to the pH of the test water with 10 molar NaOH
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no
Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
TEST ORGANISM
- Common name: zebra fish
- Strain: HAMILTON-BUCHANAN
- Source: Hoechst Marion Roussel Deutschland GmbH, Global Preclinical Development - Drug Safety
- Age at study initiation (mean and range, SD): 5 weeks
- Length at study initiation (length definition, mean, range and SD): cm ,2.7, 2.6 - 2.9, ±0.12
- Weight at study initiation (mean and range, SD): no data
- Method of breeding: no data
- Feeding during test: no

ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions (same as test or not): yes
- Type and amount of food: Tetra Min, Tetra Werke, Melle, Germany, ad libitum
- Feeding frequency: twice daily
- Health during acclimation (any mortality observed): no data
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
96 h
Hardness:
2.7 mmol Ca2+ plus Mg2+/L
Test temperature:
21.2 - 21.5
pH:
7.3 - 8.3
Dissolved oxygen:
7.2 - 9.4
Nominal and measured concentrations:
nominal: 1000 mg/L
measured: 996.3 mg/L (aritmethic mean), 993 mg/L (geometric mean) (mean of samples taken at 0 h, 48 h and 96 h)
Details on test conditions:
TEST SYSTEM
- Test vessel: cuboid test chambers situated in a water bath
- Type (delete if not applicable): no data
- Material, size, headspace, fill volume: glass, 6 L (20x15x20 cm length/width/height), 2L, 4L
- Aeration: no
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water, composition according to ISO/DIS 7346/1, no detailed information on composition or water parameter measurements

OTHER TEST CONDITIONS
- Adjustment of pH: yes; after addition of test substance, the pH of the test solution was adjusted to the original pH of the dilution water (7.9 - 8.2) with 10 molar NaOH
- Photoperiod: 12 h light /12 h dark
- Light intensity: 700 lux directly above the chambers

EFFECT PARAMETERS MEASURED (with observation intervals if applicable)
- Conditions of fish (lethality, appearance, behaviour): after 3, 6 ,24, 48, 72, and 96 h
- Temperature: at 0, 24, 48, 72, and 96 h
- O2 concentration: at 0, 24, 48, 72, and 96 h
- pH: at 0, 24, 48, 72, and 96 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: only one concentration tested
- Justification for using less concentrations than requested by guideline: limit test
- Range finding study: no data
Reference substance (positive control):
no
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: test solution was neutralized
Details on results:
- Mortality of test group: no mortalities observed
- Behavioural abnormalities: up to 24 h some fish showed hypoactivity, tail heavy swimming posture, projecting opercula, and irregular respiration
- Observations on body length and weight: no data
- Other biological observations: no data
- Mortality of control: none
- Other adverse effects control: no data
- Abnormal responses: no
Validity criteria fulfilled:
yes
Conclusions:
No mortality was observed in a test group of seven fish, exposed for 96 h to a test concentration of 1000 mg/L of neutralized 2-methylbutyric acid.
Executive summary:

2-Methylbutyric acid (2 -MBA) was tested in zebra fish (Brachydanio rerio) over 96 hours in a static system. The study was performed acc. to OECD 203 and in compliance with GLP. The concentration tested was 1000 mg/L (limit test) and a negative control (0 mg/L). After adding the substance, the pH fell to a value of 4.0. It was then adjusted to the pH of the test water with 10 molar NaOH. The tested concentration was present as a clear solution. The test concentration was analytically verified. The values determined were in a range of ± 20 % of the theoretical value and therefore, effect concentrations were based on nominal concentrations.

Fish exposed to 2 -MBA showed changes in behaviour, swimming behaviour and respiration rate. The effects were reversible from 48 hours after exposure. No mortality occurred. Therefore, the 96-LC50 was > 1000 mg/L.

The validity criteria of the test guideline were fulfilled. The study was reliable and adequate for the environmental hazard assessment for aquatic organisms.

Description of key information

96-LC50 (Brachydanio rerio) > 1000 mg/L (nominal, OECD 203, 1997)

Key value for chemical safety assessment

Additional information

A reliable supproting study is available for the submission substance (RL1). 2-Methylbutyric acid (2 -MBA) was tested in zebra fish (Brachydanio rerio) over 96 hours in a static system. The study was performed acc. to OECD 203 and in compliance with GLP. The concentration tested was 1000 mg/L (limit test) and a negative control (0 mg/L). After adding the substance, the pH fell to a value of 4.0. It was then adjusted to the pH of the test water with 10 molar NaOH. The test concentration was analytically verified. Fish exposed to 2 -MBA showed changes in behaviour, swimming behaviour and respiration rate. The effects were reversible from 48 hours after exposure. No mortality occurred. Therefore, the nominal 96-LC50 was > 1000 mg/L.

The study fulfilled the validity criteria of the guideline. The study was considered reliable and adequate for the environmental hazard assessment for aquatic organisms.