2(3H)-Benzofuranone, 5,7-bis(1,1-dimethylethyl)-3-(4-hydroxy-3,5-

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction product of: 3-hydroxy-5,7-di-tert-butylbenzofuran-2-one with o-xylene

EC Number:

417-100-9

EC Name:

Reaction product of: 3-hydroxy-5,7-di-tert-butylbenzofuran-2-one with o-xylene

Cas Number:

181314-48-7

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

During the test samples for analysis were taken from the control, the Cremophor-control, from the supersaturated solution of nominally 100 mg/l and its filtrate.
Sampling: Frequency at t=Oh and t=48h.
Volume 10 ml from the approximate centre of the test vessel.
Storage The samples were stored in a deep-freeze until analysis.

Test solutions

Vehicle:

yes

Details on test solutions:

According to data of the sponsor, water solubility of the test substance was < 0.05 mg/l. Therefore, the test substance solution was prepared by mixing 30.4 and 30.0 mg of test substance with 30.2 and 29.9 mg of Cremophor EL in 300 ml of ISO-medium, respectively. These dispersions were stirred for ca. 94 hours before the start of the exposure. Subsequently, one of these dispersions was filtered through a paper filter and as such tested, i.e. 2 x 80 ml divided over 2 vessels. From the other stirred dispersion also 2 x 80 ml were taken and tested without filtration. The filtrate was turbid while the unfiltered solution was turbid with larger undissolved test substance particles dispersed through the medium.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna (Crustacea, Cladocera) (Straus, 1820)
Reason for selection: This system has been selected as an internationally accepted species.
Validity of batch: Frequent inspection of the cultures with respect to number of young, appearance of young and parental daphnia and global feeding behaviour.
Characteristics: For the test selection of young daphnia with an age of < 24 hours.
Start of each batch: With newborn animals, i.e. less than 3 days old, by placing about 250 of them into 10 litres of medium in an all-glass culture
vessel.
Maximum age of the cultures: 4 weeks
Renewal of the cultures: After 7 days of cultivation half of the medium twice a week.
Temperature of medium: 18-22°C, constant within + 1°C
Feeding: Daily, a suspension of fresh water algae.
Medium: M4, as prescribed by Dr. Elendt-Schneider (Elendt, B.-P., 1990: Selenium deficiency in Crustacea. An ultrastructural approach to antennal damage in Daphnia magna Straus. Protoplasma 154, 25-33).

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

250 mg/l expressed as CaCO3

Test temperature:

18-22 °C, constant within +- 1°C

pH:

7.9 - 8.1

Dissolved oxygen:

9.3 - 9.5

Salinity:

n/a

Nominal and measured concentrations:

100 mg/L nominal filtered - 6 to 19 mg/L measured
100 mg/L nominal unfiltered - 5 to 45 mg/L measured

Details on test conditions:

According to data of the sponsor, water solubility of the substance was < 0.05 mg/l. Therefore, the test substance solution was prepared by mixing 30.4 and 30.0 mg of test substance with 30.2 and 29.9 mg of Cremophor EL in 300 ml of ISO-medium, respectively. These dispersions were stirred for ca. 94 hours before the start of the exposure. Subsequently, one of these dispersions was filtered through a paper filter and as such tested, i.e. 2 x 80 ml divided over 2 vessels. From the other stirred dispersion also 2 x 80 ml were taken and tested without filtration. The filtrate was turbid while the unfiltered solution was turbid with larger undissolved test substance particles dispersed through the medium.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 45 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

supersaturated solution

Details on results:

Under the conditions of the present study, Daphnia magna were not affected by exposure to a highly supersaturated solution with undissolved test substance particles kept in an unstable dispersion. The 48h-EC50 for immobilization of daphnia was greater than 45 mg/l the maximum attainable concentration of the test substance.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes