Benzeneacetic acid, .alpha.,.alpha.-dimethyl-, ethyl ester

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:

Start of study: January 26 - End of study: January 28, 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: 1a: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes

Remarks:

Principles of Good Laboratory Practice, annex of paragraph 19a, section 1 of the chemical law

Test material

Test material information

Constituent 1

Reference substance name:

α,α-Dimethyl-ethyl ester benzeneacetic acid

EC Number:

608-307-7

Cas Number:

2901-13-5

Molecular formula:

C12 H16 O2

IUPAC Name:

α,α-Dimethyl-ethyl ester benzeneacetic acid

Details on test material:

Name: EDMPA
Synonyms: Ethyldimethylphenylacetat, 2-Phenylisobutyrsäureethylester
Chemical name: 2-methyl-2-phenyl-propionic acid ethyl ester
Certificate of analysis: August 26, 1999
Purity: 99.8%
Appearance: clear, colorless liquid
Batch number: C 0086
Date of production: August 26, 1999
Date of expiry: August 26, 2000
Storage conditions: darkness at approximately 5°C in a refrigerator

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The samples were diluted with water.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: Stock culture of Aventis Pharma Deutschland GmbH, ProTox
- Feeding during test: daphnids were not fed during the entire study period.
- Food type: The supplied diet was based on the amount of organic carbon (C).
- Amount: The ration level is 0.2 mg carbon/day/animal.
- Frequency: three times a week with monocellular green algae (Scenedesmus subspicatus).

ACCLIMATION
- Feeding frequency: three times a week with monocellular green algae (Scenedesmus subspicatus).

Study design

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

48 h

Test conditions

Hardness:

2.3 mmol Ca²+ + Mg²+/L

Test temperature:

21 ± 1 °C

pH:

Control group: 7.9-8.0
Controls: 7.8-7.9

Dissolved oxygen:

Control group: 8.8-9.3 mg/L
Controls: 8.9-9.1 mg/L

Nominal and measured concentrations:

Nominal test concentrations: 0-10-22-50-100 mg/L
Mean measured concentrations: 0-12.6-20.6-47.4-85.5 mg/L

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: 250 ml beakers (height 110 mm, diameter 70 mm, water level about 75 mm), each filled with 200 ml test water.
- No. of organisms per vessel: 10 daphnids (=20/concentration) in each test chamber

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted fresh water was used for breeding and dilution. Demineralized water with a conductance of < 1 µS/cm was used for preparing the artificial fresh water (according to Elendt).
- Ca/mg ratio:6.57
- Conductivity: < 1 µS/cm

- Light intensity: The room was illuminated by fluorescent tubes for 16 hours each day.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 24h
- Test concentrations: 0/10/22/50/100 mg/L

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

12.6 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

12.6 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mobility

Effect concentrations 3

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

39.2 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Remarks on result:

other: 32.1-47.0

Effect concentrations 4

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

36.9 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mobility

Remarks on result:

other: 30.4-43.9

Effect concentrations 5

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

33.2 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Remarks on result:

other: 27.8-39.6

Effect concentrations 6

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

31.3 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mobility

Remarks on result:

other: 26.1-37.4

Effect concentrations 7

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

85.5 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mobility

Effect concentrations 8

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

85.5 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mobility

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

EC50 (48h) = 33.2 mg/l under the conditions of the test.