tert-butylbenzene

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:

2018

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)

Version / remarks:

OECD 202 (2004)

Deviations:

not specified

GLP compliance:

yes

Specific details on test material used for the study:

- Name of test material: tert-butylbenzene
- IUPAC name: tert-Butylbenzene
- Molecular formula: C10H14
- Molecular weight: 134.22 g/mol
- Substance type: Organic
- Physical state: Liquid

Analytical monitoring:

not specified

Vehicle:

no

Details on test solutions:

The primary stock solution used in the range-finding test was prepared by dissolving 10 mg of the test substance in 40 mL of dilution water – M4 and the total volume was completed to 100 mL, resulting in a concentration of 100 mg.L-1. The secondary stock solutions of the 10 and 1 mg.L-1 were prepared by dilution of the primary stock solution.

The primary stock solution used in the definitive test was prepared by dissolving 50 mg of the test substance in 40 mL of dilution water – M4 and the total volume was completed to 500 mL, resulting in a concentration of 100 mg.L-1.

Test organisms (species):

Daphnia magna

Details on test organisms:

The test system used for this study is described below, according to Straus (1820):

Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Branchiopoda
Order: Cladocera
Family: Daphniidae
Genus: Daphnia
Species: Daphnia magna

Young Daphnia magna ≤ 24 hours old were obtained from the culture kept at the Ecotoxicology Laboratory, maintenance and cultivation records are archived at BIOAGRI.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

148.1 mg.L-1 CaCO3

Test temperature:

20.2 to 20.3°C

pH:

7.7 to 7.8

Dissolved oxygen:

8.0 mg.L-1

Nominal and measured concentrations:

In the range-finding test the exposure conditions were: control; 0.1; 1; 10 and 100 mg.L-1;
In the definitive test the exposure conditions were: control and 100 mg.L-1

Details on test conditions:

TEST SYSTEM
Test vessel: 30 mL glass beakers

In the range-finding test the exposure conditions were:

a) Total number of organisms per each tested concentration or control: 10;
b) Number of replicates per each tested concentration and control: 2;
c) Number of organisms per test container: 5;
d) Volume: 15 mL of test solution per test container, 3 mL to each Daphnia;
e) The organisms were distributed randomly in the test container. Firstly, three organisms were placed in each test container and, finally, two organisms were added to the container;
f) Nominal used concentrations: control; 0.1; 1; 10 and 100 mg.L-1;
g) Temperature of the test solutions: 20.2 to 20.3°C;
h) Photoperiod: 16 hours of light and 8 hours of dark;
i) Parameters evaluated: immobility after 24 and 48 hours; and still animals were considered unable to swim for a period of 15 seconds of observation after mild agitation of the flasks.

In the definitive test the exposure conditions were:

a) Total number of organisms per each tested concentration or control: 20;
b) Number of replicates per each tested concentration and control: 4;
c) Number of organisms per test container: 5;
d) Volume: 15 mL of test solution per test container, 3 mL to each Daphnia;
e) The organisms were distributed randomly in the test container. Firstly, three organisms were placed in each test container and, finally, two organisms were added to the container;
f) Nominal used concentrations: control and 100 mg.L-1;
g) Temperature of the test solutions: 20.0 to 20.3°C;
h) Photoperiod: 16 hours light and 8 hours dark;
i) Parameters evaluated: immobility after 24 and 48 hours; and still animals were considered unable to swim for a period of 15 seconds of observation after mild agitation of the flasks;
j) Analytical determination: content dissolved oxygen, pH of the test solutions and the test substance concentration were determined at the beginning of the test and after 48 hours.



TEST MEDIUM / WATER PARAMETERS
Source/preparation of dilution water: M4 (OECD 202)
pH: 7.7 to 7.8
Hardness: 148.1 mg.L-1 CaCO3
Dissolved oxygen: 8.0 mg.L-1
Temperature: 20.2 to 20.3 °C

Reference substance (positive control):

yes

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50 (24 h): 1.06 mg/L (95% confidence limits = 0.93 to 1.22 mg.L-1).

Validity criteria fulfilled:

yes

Conclusions:

The 48-hours EC50 value was not determined because the highest tested concentration of Tert-Butylbenzene, 100 mg/L, did not cause immobility to the test organisms. Therefore the 48-hours EC50 value of the tested substance is higher than 100 mg/L.

Executive summary:

Assessing the toxicity to aquatic invertebrates, Daphnia magna was exposed to tert-butylbenzene for 48 hours. The experiment was conducted according to OECD Guideline 202 (2004). The test gave a 48-h EC50 value of higher than 100 mg/L .

Description of key information

Study carried out according to guideline and with GLP compliance.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

In a static test conducted according to OECD 202 guideline an EC50 of higher than 100 mg/L after 48 h based on mean measured concentration has been determined.