p-tert-butylstyrene

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:

20 February 2017 - 30 April 2019

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

Specific details on test material used for the study:

Synonyms: p-tert-butylstyrene
CAS No: 1746-23-2
Purity: 95.9%

Analytical monitoring:

yes

Details on sampling:

- Nominal Concentrations: 0.097, 0.21, 0.47, 1.0, 2.3 and 5.0 mg/L
- Sample storage conditions before analysis: Test substance was stored in a refrigerator (2 to 8°C) in the original container.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

Primary stock solution concentration: 50 mg/ml
Stock solution vessel and volume: 25-mL volumetric flask
Amount f test stubstance added: 1.2970 g (1.2438 g as active ingredient)
Dilutent: DMF

The primary stock solution was mixed with inversions of the flask and was observed to be clear and colorless with no visible undissolved test substance following preparation.

Secondary stock solutions were mixed with inversions of the flask and were observed to be clear and colorlss with no visible undissolved test substance following preparation

Exposure solutions were mixed thoroughly using a a glass rod for appropximately one minute. The exposure solutions were observed to be clear and colorless with no visible undissolved test substance following preparation. Negative control and solvent control vessels were maintained under the same conditions as the treatment level solutions.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia Magna
Source: Smithers Viscient culture
Age: < 24 hours old
Culture Vessel: 1.0 L glass beaker containing 0.80 L of water
Food Type: Unicellular green algae, ankistrodesmus falcatus (4x10^7 cells/mL) and a suspension of YCT (yeast, cereal leaves and flaked fish food)
Feeding Frequency: Once daily during culture
Ephippia Observed: No
Offspring Released in Culture prior to Day 12: Yes
Mortality of Culture Adults: <20% two days prior to initiation
Average Amount of Offspring: >=3 offspring per adult 7 days prior to initiation
Offspring used in a previous Test: No

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

180 mg/L

Test temperature:

19 - 22°C

pH:

7.5 - 8.0

Dissolved oxygen:

7.5 - 8.0 mg/L

Conductivity:

710 - 840 us/cm

Nominal and measured concentrations:

Nominal Concentrations: 0.097, 0.21, 0.47, 1.0, 2.3, and 5.0 mg/L
Geometric Mean Measured Concentrations: 0.085, 0.18, 0.46, 0.85, 2.0, and 4.4 mg/L

Details on test conditions:

Duration: 48 hours
Expsure system: Static-renewal, closed-system conditions
Temperature: 20 to 21°C
Photoperiod: 16 hours light: 8 hours dark
Light Intensity: 32 to 75 footcandles (340 to 810 Lux) measured around the test area once during the exposure with VWR traceable light meter.

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.63 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.18 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Validity Criteria
Control(s) immobilization (or other signs of stress) not exceeding 10% at exposure termination

Dissolved Oxygen Range of greater than or equal to 3 mg/L

Study Results
Immobilization in the negative control and solvent control was 0%

Dissolved oxyten in the controls and exposure vessels ranged from 8.2 to 9.0 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test material to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EC50 value of 0.63 mg/L. The No Observed Effect Concentration is 0.16 mg/L. The Lowest-Observed-Effect Concentration is 0.46 mg/L.

Executive summary:

A study was conducted to determine the short term toxicity of the substance to the freshwater invertebrate, Daphnia magna, according to OECD Guideline 202, in compliance with GLP. Groups of daphnids were exposed to nominal test substance concentrations of 0.097, 0.21, 0.47, 1.0, 2.3 or 5.0 mg/mLunder static conditions for 48 h. During the exposure period, the daphnids were observed for mortality and mobility. All validity criteria were fulfilled. Under the study conditions, the 48 h EC50 of the test substance in Daphnia magna was determined to be 0.63 mg/L (Smithers Viscient, 2019).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.63 mg/L

Additional information

A study was conducted to determine the short term toxicity of the substance to the freshwater invertebrate, Daphnia magna, according to OECD Guideline 202, in compliance with GLP. Groups of daphnids were exposed to nominal test substance concentrations of 0.097, 0.21, 0.47, 1.0, 2.3 or 5.0 mg/mLunder static conditions for 48 h. During the exposure period, the daphnids were observed for mortality and mobility. All validity criteria were fulfilled. Under the study conditions, the 48 h EC50 of the test substance in Daphnia magna was determined to be 0.63 mg/L (Smithers Viscient, 2019).