Isobutyl isobutyrate

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:

1994

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Aliquots of the exposure solutions were submitted for concentration dterminations at times 0 24, 48, 72, and 96 hours. The exposure solutions containing nominaly 111.0 mg/L (replicate A) and 200.0 mg/L ( replicates A and B) were submitted at 0 and 24 hours as 100% mortality was observed among the test organisms in these replicates at 24 hours of exposure.

Vehicle:

no

Details on test solutions:

Test solutions were prepared in replicate (i.e., A and B) and results were reported for each replicate

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name: Fathead Minnow
- Strain:
- Source: Aquatic Research Organisms, Hampton, New Hampshire
- Age at study initiation (mean and range, SD): 32 days old
- Length at study initiation (length definition, mean, range and SD): 2.17 cm (1.7 to 2.6 cm range) and 1.98 cm (1.6 to 2.6 cm range) representing two separately measured replicates
- Weight at study initiation (mean and range, SD): 0.11 g
- Method of breeding:
- Maintenance of the brood fish:

ACCLIMATION
- Acclimation period: 2 weeks
- Acclimation conditions (same as test or not): Same
- Type and amount of food during acclimation:
- Feeding frequency during acclimation:
- Health during acclimation (any mortality observed):

QUARANTINE (wild caught)
- Duration:
- Health/mortality:

FEEDING DURING TEST
- Food type:
- Amount:
- Frequency:

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

120 mg/L

Test temperature:

20 +/- 1 degress Celsius

pH:

7.4 to 9.0

Dissolved oxygen:

7.9 to 9.0

Salinity:

not applicable

Nominal and measured concentrations:

10.5, 19.0, 34.5, 61.5, 111.0 and 200 mg/L

Details on test conditions:

acute tests were performed in seamless Pyrex glass 30.5 cm cuboidal chromatography jars containing 20 L of exposure solution.

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

14.22 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other:

Remarks:

replicate A

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

12.5 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other:

Remarks:

replicate B

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

9.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other:

Remarks:

replicate A

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

9.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other:

Remarks:

replicate B

Details on results:

The test material concedntrations used in the LC50 calculations were dervied from the mesaure mean values of the seasoned and renewed exposure solutions at times 0 and 24 hours (nominally, 110.0 mg/L replicate A, and 200.0 mg/L replicates A and B) and times 0, 24, 48, 72, and 96 hours (all reamaining seasoned and renewed test article solutions).

Reported statistics and error estimates:

A computer program developed by C.E. Stephan and ASTM was used to compute point and interval estimates ot the LC50 values for this test.

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of the test article, as measured by the 96-hour LC50 values, did not vary considerably over the course of the study. The 96-hour Lc50 values, were 14.2 mg/L and 12.5 mg/L, for replicates A and B, respectively. The lowest of these two replicates 12.5 mg/L will be the LC50 value used for the risk assessement and to develop environmental concetration limits.

Executive summary:

The acute toxicity of Isobutyl Isobutyrate to the fathead minnow, Pimephales promelas, was determined in a 96 -hrm semi-static, aquatic effects test. The test material solutions and water controls were freshly prepared (renewed) every 24 hours. At each renewal perios, the fish were transferred from the 24 -hour old solutions to the renewed solutions. After preparation of each renewed solution, samples of the seasoned solutons and the renewed solutions of each replicate containing the test material and control solutions were submitted for chemical analysis. Replicate servies fish mortality results were not pooled for input into the LC50 program. the 24, 48, 72, and 96 -hour LC50 values for P. promelas for replicate servies A were calculated to be 17.5, 15.7, 15.1 and 14.2 mg/L, respectively. The 24, 48, 72 and 96 -hour LC50 values for replicate B were 23.3, 21.2, 15.8 and 12.5 mg/L.

Description of key information

An acute toxicity study was conduct with the Fathead Minnow, Pimphelas promelas, following OECD 203. The result from each of two replicates was reported based ono mean measured concentrations. The reported LC50 was based on the geometric mean of the replicate data and resulted in an 96 -hr LC50 value of 13.3 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

13.3 mg/L