Isobutyric acid

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1989-06-26 - 1989-06-30

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure according to national standards; comparable to guideline study with acceptable restrictions (test substance concentrations not measured, only four test concentrations tested)

Qualifier:

according to guideline

Guideline:

other: German industrial standard test guideline DIN 38 412, part L15.

Principles of method if other than guideline:

Test method is a short-term toxicity test for fish similar to OECD test guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The doses were chosen based on a range finding study.
The product was added to the test water without any pretreatment; subsequently the fish were placed into the aquaria

Test organisms (species):

Leuciscus idus

Details on test organisms:

TEST ORGANISM
- Common name: Goldorfe
- Strain: Leuciscus idus (golden variety)
- Source: Fischzucht Paul Eggers, 2354 Hohenwestedt, Germany
- Length at study initiation: 7.2 cm (range: 6.2-7.9)
- Weight at study initiation: 3.5 g (range: 2.4-4.4)
- Feeding during test: no
- Frequency: Withdrawal of food before exposure: 1 day


ACCLIMATION
- Acclimation conditions (same as test or not): oil-free aerated water
Water temperature: 21°C
Acclimation to test water and test temperature: 3 days

- Type and amount of food: Growing feed, F/B 50, SSNIFF Spezialdiaeten GmbH, Soest, Germany
- Feeding frequency: ad libitum.

HOUSING
- Housing water: charcoal filtered dechlorinated water in continuous flow-through
- Aeration: oilfree air
- Light regime: 16 : 8 hours light : dark
- Hardness: 2.5 mM
- Oxygen concentration: > 60 % of maximum saturation
- pH: about 8.0
- Water temperature: 20 ± 1 °C
- Duration of housing: about 3 month
- Medical treatment: Twice with 0.05 mg/L Malachitegreen and once with 10 mg/L tetracyclinhydrochlorid
- Feeding: Growing feed, F/B 50, SSNIFF Spezialdiaeten GmbH, Soest, Germany
- Amount of feed: ad libitum
- Mortality during the last 2 weeks of housing: 0.2 %

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Hardness:

Total hardness: 2.5 mmol/L

Test temperature:

21 °C

pH:

about 8.0

Dissolved oxygen:

6.8 - 8.5 mg/L

Nominal and measured concentrations:

Nominal concentrations: control, 100, 215, 464, 1000 mg/L. Additionally: Neutralised samples: 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): aquaria open
- Material, size, fill volume: glass, 30 x 22 x 24 cm, 10 L
- Aeration: aeration with oil-free air
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 3.5 g fish /L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted freshwater according to DIN 38412, part 11
- Ca/Mg ratio: 4 : 1
- Intervals of water quality measurement: 1, 24, 48, 72, and 96 hours

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

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality, symptoms

Reference substance (positive control):

yes

Remarks:

Chloracetamid

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

146.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: not neutralised samples

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

215 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: not neutralised samples

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: neutralised sample

Details on results:

- Behavioural abnormalities: narcotic like stage

Results with reference substance (positive control):

- Results with reference substance valid? yes
- LC50: ca. 25 mg/L (48 h)

Validity criteria fulfilled:

yes

Conclusions:

The actual pH in the test vessel may be different from the reported value (about 8.0). pH values after addition of test substance (carboxylic acid) to the test water are not reported.

Description of key information

Three different fish species were tested in short term toxicity fish tests
Golden orfe (Leuciscus idus): 96-h LC50 = 146.6 mgTS/L (similar to OECD TG 203; BASF AG, 1989)
Rainbow trout (Oncorhynchus mykiss): 96-h LC50 = 286 mg mg/L (similar to OECD TG 203; Hoechst AG, 1979)
Pumpkinseed (Lepomis gibbosus): 96-h LC50 = 435 mg/L (similar to OECD TG 203; Hoechst AG, 1979)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

146.6 mg/L

Additional information

In three individual short term (96 hr) tests, the toxicity of isobutyric acid to three fish species was tested. All tests were performed using the same method (similar to OECD TG 203). Although there are some restrictions (test substance concentration not measured, only four concentrations tested) the studies are assessed as acceptable.

 

There was no adjustment of pH. In two tests (Hoechst AG), pH-values were measured after addition of the test substance to the dilution water. Values in the test medium declined in a concentration dependent manner within 24 hours to a pH as low as 4.6.

 

The 96 -h LC50 for golden orfe (Leuciscus idus) was 146.6 mg/L (BASF AG, 1989).

The 96-h LC50 for rainbow trout (Oncorhynchus mykiss) was 286 mg/L (Hoechst AG, 1979).

The 96-h LC50 for pumpkinseed (Lepomis gibbosus) was 435 mg/L (Hoechst AG, 1979).

 

Sublethal effects were discoloration, imbalance, uncoordinated movements, and dorsal and lateral position. Fish of the three highest dose groups were narcotized. In sacrificed pumpkinseed (dose group 315 and 500 mg/L), light discoloration of livers were observed.

 

For high test substance concentrations, the observed toxicity may have been influenced by the acidic conditions of the test medium.