4-formyl-2-methoxyphenyl isobutyrate

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:

30 June - 10 November 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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test material (as cited in study report): Isobutavan
- Physical state: colourless to pale yellow liquid
- Lot/batch No.: SC00010048
- Expiration date of the lot/batch: December 17, 2015
- Storage condition of test material: ambient temperature, dark

Analytical monitoring:

yes

Details on sampling:

Analytical samples were taken from all test concentrations and control(s) at test start (fresh) and after 24 hours (aged). After 24 hours analytical samples were taken from control, 6.25, 12.5, 25.0 and 50.0 mg/L from fresh test solutions and after 48 hours from aged test solutions.
All test item concentations and control were analysed at t = 0 hours from fresh test solution and after 24 hours from aged test solution. At 24 hours samples of 6.25, 12.5, 25.0 and 50.0 mg/L were analysed from fresh test solutions. Stability of the test item in test solutions could be shown by analysis covering one 24 hour interval. Thus samples taken after 48 hours from aged test solutions were not analysed.

Vehicle:

no

Details on test solutions:

Following a range finding test at concentrations of 1.0, 10.0, and 100 mg/L test material, it was determined that the concentrations to be used in the final test were 0, 6.25, 12.5, 25.0, 50.0, and 100 mg/L. The necessary amount of the test item for preparing the stock solution was weighed on weighing scoops and transferred to a volumetric flask. Test medium was added up to the bench mark and the solution was homogenised by shaking. The lower test solutions were prepared by dilution of the stock solution. Defined volumes of the prepared solution were transferred to each test vessels. The test solution volume was 50 mL per test vessel.

Test organisms (species):

Daphnia magna

Details on test organisms:

As test organism, Daphnia magna STRAUS, Clone V, was used. The animals are continuously bred in the laboratory and were originally purchased in a
healthy condition from the Umweltbundesamt in Berlin, Germany.
Daphnia magna was bred as single culture (1 daphnid per 50 mL) in Elendt M4 medium. Daphnia magna was bred as single culture (1 daphnid per 50 mL) 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, formerly Scenedesmus subspicatus) at least three times a week. The daphnids were reared at a temperature of 20 ±2oC in a climatic chamber
with 16 h of illumination and 8 h of darkness.
Freshly hatched daphnids max. 24 hours old were used for the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20.0 – 20.8 °C

pH:

7.75 – 8.02

Dissolved oxygen:

8.5 – 8.8 mg/L

Nominal and measured concentrations:

Nominal concentrations were 0, 6.25, 12.5, 25.0, 50.0, and 100 mg/L.
The initial measured concentration of Isobutavan in the samples ranged between 92 and 100 % of nominal. The mean measured content of Isobutavan in the samples at 0, 24 hours (aged) and 24 hours (fresh) was 91 % of nominal. Therefore the toxicological endpoints were evaluated using nominal concentrations of the test item.

Details on test conditions:

The daphnids were exposed to a control and increasing concentrations of the test item for 48 hours, with a renewal of the test solutions after 24 hours. Two concentrations of the reference item potassium dichromate (1.0 mg/L, 2.0 mg/L) were tested around the same time period as the study.
The test was semi-static and conducted in four 100 mL glass beakers per concentration, each filled with 50 mL, loosely covered by a glass plate. 20 animals were used per concentration in 4 replicates of 5. Test organisms were not fed during the test.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

36.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% C.L. 32.3 - 40.6 mg/L

Details on results:

After 24 hours of exposure no immobilisation was observed in the control and at the test concentrations of 6.25, 12.5 and 25.0 mg/L. 80 % immobilisation was observed at 50.0 mg/L and 100 % immobilisation at the highest test item concentration level of 100 mg/L. At 50.0 and 100 mg/L daphnids were observed at the surface of the test vessel. After 48 hours of exposure no immobilisation was observed in the control and at test concentrations up to and including 25.0 mg/L. 95 % immobilisation was observed at 50.0 mg/L and 100 % immobilisation at the highest test item concentration level of 100 mg/L.

Results with reference substance (positive control):

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 36.2 mg/L (nominal). The corresponding NOEC (48 h) was determined to be 25.0 mg/L (nominal) of the test item.

The toxicological endpoints were evaluated using nominal concentrations because the measured concentrations of the test item were within the recommended range of 80 % and 120 % nominal (actual range = 91-100% nominal).

Executive summary:

An OECD 202 acuteDaphnia magnaimmobilisation test was conducted for the substance Isobutavan. Following a range-finding test, juvenileDaphnia magnafrom in-house cultures were exposued to Isobutavan at concentrations of 0, 6.25, 12.5, 25.0, 50.0, and 100 mg/L. The test was semi-static and conducted in four 100 mL glass beakers per concentration, each filled with 50 mL, loosely covered by a glass plate. 20 animals were used per concentration in 4 replicates of 5. Test organisms were not fed during the test. The photoperiod was 16 hours light to 8 hours dark. the pH of the test solutions was 7.75-8.02, the test temperature was 20.0-20.8^oC.

After 24 hours of exposure no immobilisation was observed in the control and at the test concentrations of 6.25, 12.5 and 25.0 mg/L. 80 % immobilisation was observed at 50.0 mg/L and 100 % immobilisation at the highest test item concentration level of 100 mg/L. At 50.0 and 100 mg/L daphnids were observed at the surface of the test vessel. After 48 hours of exposure no immobilisation was observed in the control and at test concentrations up to and including 25.0 mg/L. 95 % immobilisation was observed at 50.0 mg/L and 100 % immobilisation at the highest test item concentration level of 100 mg/L.

According to the results of the test, the EC50 (48 h) for immobilisation was determined to be 36.2 mg/L (nominal). The corresponding NOEC (48 h) was determined to be 25.0 mg/L (nominal) of the test item.

Description of key information

EC50 (48 h) = 36.2 mg/L (nominal)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

36.2 mg/L

Additional information

An OECD 202 acuteDaphnia magnaimmobilisation test was conducted for the substance Isobutavan. Following a range-finding test, juvenileDaphnia magnafrom in-house cultures were exposued to Isobutavan at concentrations of 0, 6.25, 12.5, 25.0, 50.0, and 100 mg/L. The test was semi-static and conducted in four 100 mL glass beakers per concentration, each filled with 50 mL, loosely covered by a glass plate. 20 animals were used per concentration in 4 replicates of 5. Test organisms were not fed during the test. The photoperiod was 16 hours light to 8 hours dark. the pH of the test solutions was 7.75-8.02, the test temperature was 20.0-20.8^oC.

After 24 hours of exposure no immobilisation was observed in the control and at the test concentrations of 6.25, 12.5 and 25.0 mg/L. 80 % immobilisation was observed at 50.0 mg/L and 100 % immobilisation at the highest test item concentration level of 100 mg/L. At 50.0 and 100 mg/L daphnids were observed at the surface of the test vessel. After 48 hours of exposure no immobilisation was observed in the control and at test concentrations up to and including 25.0 mg/L. 95 % immobilisation was observed at 50.0 mg/L and 100 % immobilisation at the highest test item concentration level of 100 mg/L.

The initial measured content of Isobutavan in the samples ranged between 92 and 100 % of nominal. The mean measured content of Isobutavan in the samples at 0, 24 hours (aged) and 24 hours (fresh) was 91 % of nominal. Therefore toxicological endpoints were evaluated using nominal concentrations of the test item.

According to the results of the test, the EC50 (48 h) for immobilisation was determined to be 36.2 mg/L (nominal). The corresponding NOEC (48 h) was determined to be 25.0 mg/L (nominal) of the test item.