4-formyl-2-methoxyphenyl 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:

04 August 2014 - 12 January 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity 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 taken at t = 0, 24, 48 and 72 h from fresh test solutions and at t = 24 h from aged test solutions from control, 1.71 and 3.76 mg/L were analysed. Samples taken at t = 0, 24, 48 and 72 h from fresh test solutions and at t = 24, 48, 72 and 96 h from aged test solutions from 8.26 mg/L were analysed, respectively. Samples taken at t = 0 h fresh and t = 24 h aged from 18.2 and 40.0 mg/L were analysed, respectively.

Vehicle:

no

Details on test solutions:

The test medium was water composed of dechlorinated drinking water and deionised water with a conductivity of 394 μS/cm.
The test concentrations were selected on basis of a limit test and subsequent non-GLP range-finding test. Test concentrations chosen for the definitive test were 1.71, 3.76, 8.26, 18.2, and 40.0 mg/L. As the test was performed as a semi-static test, each day the necessary amount of test item for preparing the stock solutions was weighed on a weighing scoop and transferred directly into the test medium in the aquaria. The solution was homogenised by stirring for five minutes.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Species: Oncorhynchus mykiss (Walbaum)
Size: 4-6 cm
Producer: Fischzucht Peter Stork, Wagenhausen, Germany
Acclimatisation: Fish for the test were obtained from the supplier on 26 August 2014 (acclimatisation > 12 days) and held under testing conditions in 300 L containers with continuous renewal of water (5 - 10 % per day) and permanent aeration of water. The fish were held under identical conditions for the entire pre-experimental period. The last feeding was performed 24 hours prior test start.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

8°dH corresponding to 143 mg CaCO3/L

Test temperature:

15.4 – 16.2 °C

pH:

7.61 – 8.33

Dissolved oxygen:

> 92 % of air saturation

Nominal and measured concentrations:

Nominal concentrations were 1.71, 3.76, 8.26, 18.2, and 40.0 mg/L.
The mean measured content of Isobutavan in fresh test solutions was between 59 % and 91 % of nominal. The measured content of Isobutavan in aged test solutions was between 59 % and 74 % of nominal.

Details on test conditions:

Following OECD 126 (2010), a limit test was performed with a threshold concentration (TC) of 50.0 mg/L based on reliable algae and acute invertebrate toxicity data (EC50) to investigate if fish is the most sensitive test organism. Since all fish died within the first four hours a range-finding test was performed followed by a dose-response test with five test item concentrations (1.71, 3.76, 8.26, 18.2, 40.0 mg/L) and control with untreated test medium was conducted using a semi-static design with daily water renewal. Each test concentration and control contained seven fish. The test was performed without replication and without a reference item. The pH-value, temperature and O2 concentration were measured in 24 hour intervals in test solutions.
Exposure to light during the test was 16 hours daily. Test vessels were 25 L glass aquaria filled with 15 L. The loading was a max of 1 g fish/L. Aeration was continuous.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

5.97 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% C.L. = 4.49 - 7.94 mg/L

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

2.72 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

In the control and at the test item concentrations up to and including 3.76 mg/L no mortality was observed within the period of the test. At 8.26 mg/L one fish died after 48 hours and another fish died after 72 hours. At 18.2 mg/L all fish were found dead after 24 hours. At the highest test item concentration of 40.0 mg/L all fish were found dead after 4 hours.
The LC50 (96 h) of the test item was 9.79 mg/L (nominal). The corresponding NOEC (mortality) (96 h) was 3.76 mg/L (nominal).
Based on actual measured concentrations the LC50 (96 h) of the test item was determined to be 5.97 mg test item/L (measured). The corresponding NOEC (mortality) (96 h) was 2.72 mg test item/L (measured).

Validity criteria fulfilled:

yes

Conclusions:

According to the results of the test, the LC50 (96 h) of the test item was determined to be 9.79 mg/L (nominal). The corresponding NOEC (mortality) (96 h) was 3.76 mg/L (nominal). No sublethal effects were observed up to and including 1.71 mg/L (nominal) after 96 h. Based on actual measured concentrations the LC50 (96 h) of the test item was determined to be 5.97 mg test item/L (measured). The corresponding NOEC (mortality) (96 h) was 2.72 mg test item/L (measured). No sublethal effects were observed in the lowest test item concentration of 1.25 mg test item/L (measured) after 96 h.

Executive summary:

The aim of the study was the assessment of mortality and determination of the LC50 (96 h) of the test item in fish within the framework of laws for registration according to OECD Guideline 203 considering OECD guidance document 126. Test species: Oncorhynchus mykiss (Walbaum), size between 4 and 6 cm. Seven organisms per test concentration were used. The duration of the test was 96 hours. The test item was evaluated in a limit test at a threshold concentration of 50.0 mg/L and control, followed by a semi-static range-finding test and a dose-response test at test item concentrations of 1.71, 3.76, 8.26, 18.2 and 40.0 mg/L and control. Test solutions were prepared by dilution of the test item in test water and application of a defined volume of the stock solutions to the test vessels. Assessments on effects and mortality after 0, 4, 24, 48, 72 and 96 hours were conducted. Endpoints reported are the LC50 (96 h) and the NOEC (No Observed Effect Concentration) mortality.

Isobutavan was analytically determined to confirm the correct application of the test item. The mean measured content of Isobutavan in fresh test solutions was between 59 % and 91 % of nominal. The measured content of Isobutavan in aged test solutions was between 59 % and 74 % of nominal. Since the measured concentrations of Isobutavan in fresh and aged test item solutions were below 80 % of nominal concentrations, the biological endpoints were evaluated using nominal and measured test item concentration.

According to the results of the test, the LC50 (96 h) of the test item was determined to be 9.79 mg test item/L (nominal). The corresponding NOEC (mortality) (96 h) was 3.76 mg test item/L (nominal). No sublethal effects were observed in the lowest test item concentration of 1.71 mg test item/L (nominal) after 96 h. Based on actual measured concentrations the LC50 (96 h) of the test item was determined to be 5.97 mg test item/L (measured). The corresponding NOEC (mortality) (96 h) was 2.72 mg test item/L (measured). No sublethal effects were observed in the lowest test item concentration of 1.25 mg test item/L (measured) after 96 h.

Description of key information

LC50 (96 h) = 5.97 mg test item/L (measured)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

5.97 mg/L

Additional information

The aim of the study was the assessment of mortality and determination of the LC50 (96 h) of the test item in fish within the framework of laws for registration according to OECD Guideline 203 considering OECD guidance document 126. Test species: Oncorhynchus mykiss (Walbaum), size between 4 and 6 cm. Seven organisms per test concentration were used. The duration of the test was 96 hours. The test item was evaluated in a limit test at a threshold concentration of 50.0 mg/L and control, followed by a semi-static range-finding test and a dose-response test at test item concentrations of 1.71, 3.76, 8.26, 18.2 and 40.0 mg/L and control. Test solutions were prepared by dilution of the test item in test water and application of a defined volume of the stock solutions to the test vessels. Assessments on effects and mortality after 0, 4, 24, 48, 72 and 96 hours were conducted. Endpoints reported are the LC50 (96 h) and the NOEC (No Observed Effect Concentration) mortality.

According to the results of the test, the LC50 (96 h) of the test item was determined to be 9.79 mg test item/L (nominal). The corresponding NOEC (mortality) (96 h) was 3.76 mg test item/L (nominal). No sublethal effects were observed in the lowest test item concentration of 1.71 mg test item/L (nominal) after 96 h. Based on actual measured concentrations the LC50 (96 h) of the test item was determined to be 5.97 mg test item/L (measured). The corresponding NOEC (mortality) (96 h) was 2.72 mg test item/L (measured). No sublethal effects were observed in the lowest test item concentration of 1.25 mg test item/L (measured) after 96 h.