4-tert-butylbenzonitrile

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:

02.06. - 23.10.2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Analytical samples were taken from all test concentrations and control vessels at test start, at renewal of test solutions and 48 hours after beginning of the test.
Samples from all test item concentrations and the controls taken at t = 0 and t = 24 hours from fresh test solutions and at t = 24 hours from aged test solutions were analysed.

Vehicle:

yes

Details on test solutions:

Elendt M4 medium (composition and preparation according to OECD 202) was used as test medium for the untreated control. Elendt M4 medium was spiked with Tween 80 as emulsifier (due to the low solubility in water), not exceeding the maximum solvent concentration of 100 µL/L. This Tween solution was used as test medium for the emulsifier control and the test solutions. At test initiation the pH-value of the control (untreated test medium) was 8.02, the dissolved oxygen concentration was 8.4 mg/L and the total hardness was 14°dH (250 mg/L as CaCO3).

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain: Daphnia magna Straus, Clone V
- Source: Umweltbundesamt, Berlin, Germany
- Age at study initiation: freshly hatched, max. 24 hours old
- Method of breeding: Daphnia magna was bred as group culture (5 to 20 daphnids per litre) in Elendt M4 medium. The pH-value of the aerated water was within a range of 6.0 – 9.0. The dissolved oxygen was above 60 % saturation and the total hardness 140 - 250 mg/L (as CaCO3), corresponding to 7.8 - 14°dH. The animals were fed with single cell green algae (Desmodesmus subspicatus, former Scenedesmus subspicatus) at least three times a week.
- Feeding during test: none
- Food type: single cell green algae (Desmodesmus subspicatus)
- Frequency: at least three times a week

ACCLIMATION
Not necessary because the daphnids were bred in the laboratory under the same conditions as in the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

Not applicable

Hardness:

14 °H (250 mg/ as CaCO3)

Test temperature:

20.1 – 21.8 °C

pH:

7.79 – 8.02

Dissolved oxygen:

≥ 7.7 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal Concentration:0.854, 1.88, 4.13, 9.09, 20.0 mg/L
Measured Concentration (after 0 h fresh): 0.604, 1.51, 3.29, 7.58, 14.4 mg/L
Measured Concentration (after 24 h aged): 0.756, 1.94, 4.14, 8.89, 20.0 mg/L
Measured Concentration (after 24 h fresh): 0.684, 1.60, 3.13, 7.30, 15.2 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: four 100 mL glass beakers per concentration, each filled with 50 mL
- Aeration: none
- Test type: semi-static
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water

OTHER TEST CONDITIONS
- Adjustment of pH: pH = 7.79 - 8.02
- Photoperiod: 16 h of illumination and 8 h darkness

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2

RANGE FINDING TEST:
The non-GLP range finding test was conducted with a control, an emulsifier control and the following concentrations:
0.010, 0.10, 1.00 and 10.0 mg/L.
After 24 hours of exposure no immobilisation was observed in the controls and up to 1.00 mg/L. 40 % of the daphnids were immobilised at 10.0 mg/L.
After 48 hours of exposure no immobilisation was observed in the controls and up to 1.00 mg/L. 60 % of the daphnids were found immobile at 10.0 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.64 mg/L

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.88 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.73 mg/L

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

In order to check the validity of the results, the toxicity of the reference item potassium dichromate was tested at 1.0 and 2.0 mg/L with 20 test organisms per test concentration on 23 July 2014 around the same time period as the study with the test item. The results indicate an EC50 (24 h) of the reference item potassium dichromate between 1.0 and 2.0 mg/L. Since the results fall within the range recommended by the guideline (OECD 202), the daphnids were suitable for the determination of the toxicological effects of the test item.

Validity criteria fulfilled:

yes

Conclusions:

According to the results of the test, the EC50 (48 h) for immobilisation was determined to be 4.10 mg/L (nominal) and 3.64 mg/L (actual) of test item. The corresponding NOEC (48 h) was 1.88 mg/L (nominal) and 1.73 mg/L (actual) of 4-tert-Butylbenzonitrile.

Executive summary:

The toxicity of 4 -tert-Butylbenzonitrile on Daphnia magna was tested in a 48 hour acute immobilisation test. The test was performed semi-static according to OECD Guideline 202 ("Daphnia sp., Acute Immobilisation Test") with concentrations of 0, 0.854, 1.88, 4.13, 9.09 and 20.0 mg/L and twenty organisms per test concentration (4 replicates of 5 animals each) were used.

According to the results of the test, the EC50 (48 h) for immobilisation was determined to be 4.10 mg/L (nominal) and 3.64 mg/L (actual) of test item. The corresponding NOEC (48 h) was 1.88 mg/L (nominal) and 1.73 mg/L (actual) of 4-tert-Butylbenzonitrile.

Description of key information

Acute toxicity effects to aquatic invertebrates were observed in a 48h freshwater test according to OECD test guideline 202.

Juvenile Daphnia magna were exposed to different concentrations of 4-tert-Butylbenzonitril. An increasing rate of immobilisation depending on the concentration of the test substance could be observed.

Additional information

The toxicity of 4 -tert-Butylbenzonitrile on Daphnia magna was tested in a 48 hour acute immobilisation test. The test was performed semi-static according to OECD Guideline 202 ("Daphnia sp., Acute Immobilisation Test") with concentrations of 0, 0.854, 1.88, 4.13, 9.09 and 20.0 mg/Land twenty organisms per test concentration (4 replicates of 5 animals each) were used.

According to the results of the test, the EC50 (48 h) for immobilisation was determined to be 4.10 mg/L (nominal) and 3.64 mg/L (actual) of test item. The corresponding NOEC (48 h) was 1.88 mg/L (nominal) and 1.73 mg/L (actual) of 4-tert-Butylbenzonitrile.