tert-butyl peroxypivalate

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:

2012-02-22 to 2012-02-24

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:

13. April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

30 May 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Version / remarks:

1996

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: nominal concentrations of 4.3, 9.4, 20.7, 45.5 and 100 mg/L
- Sampling method: Four replicates samples were taken each day of study from the test solutions. The samples were diluted with acetonitrile before the measurement. Control samples were directly measured.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution of nominally 100 mg/L was first prepared by dissolving an amount of 0.10 g test item in 1000 mL ISO medium. The test solutions of the chosen test concentrations were prepared by appropriate diluting of this stock solution. The test solutions were prepared just before introduction of test animals. Preparation of test solution was performed by a same way at each water renewal period.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: waterflea
- Source: Laboratory of Hydrobiology (Central Agricultural Office, Directorate of Plant-, and Soil Protection) 2100 Gödöllő, Kotlán S. u. 3. Hungary
- Age at study initiation: less than 24 hours old
- Method of breeding: Daphnia were bred in the Laboratory of TOXI-COOP ZRT. under similar temperature and light conditions as in the test, and in reconstituted water of a similar quality regarding to pH, components of the main ions and total hardness as the test water used in the test.
- Feeding during the test: yes
- Food type: centrifuged green alga suspension

ACCLIMATION
- Acclimation period: Test animals were bred under similar conditions as that used during the exposure period, therefore additional acclimatisation before the test was not necessary.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

249 mg/L (as CaCO3)

Test temperature:

The test temperature was in the range of 21.3 – 21.8 °C measured in the test vessels during the test. The additionally measured ambient temperature within the climate chamber was between 20.3 – 21.8 °C.

pH:

The pH of the test solution was not adjusted and not varied by more than 1.5 units in any one test. The pH was in the range of 7.69 – 8.05 during the test.

Dissolved oxygen:

The dissolved oxygen concentration was in the range of 7.63 – 8.58 mg/L during the test.

Nominal and measured concentrations:

4.3, 9.4, 20.7, 45.5 and 100 mg/L nominal concentration
2.94, 6.51, 14.44, 31.76 and 64.65 mg/L measured concentration

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers of approximately 40 mL test medium
- Type: vessel (including control) was sealed in order to minimize possible evaporation and thus decline of test concentration
- Renewal rate of test solution: 24 hours
- No. of organisms per vessel: 5 organisms per vessel
- No. of vessels per concentration: 4 replicates
- No. of vessels per control (replicates): 4 replicates

TEST MEDIUM / WATER PARAMETERS
- according to the guideline

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light (artificial illumination) and 8 hours darkness

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

6.99 mg/L

95% CI:

5.87 - 8.51

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

2.94 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

6.51 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

14.44 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Mortality of control: The immobilisation rate of the introduced Daphnia did not exceed 10 %.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50/LC50: The 24-h EC50: 2.05 mg/L, (95 % confidence limits: 1.76 – 2.43 mg/L)

Reported statistics and error estimates:

The 24-h and 48-h EC50 values of the test item and their confidence limits were calculated using Probit analysis by SPSS PC+ software. For determination of NOEC, LOEC and EC100 were determined directly from the raw data.

Validity criteria fulfilled:

yes

Conclusions:

The 48 h EC50 value was determined as 6.99 mg/L, and the 48 h NOEC was determined to be 2.94 mg/L. The results are based on the measured geometric mean test item concentrations.

Executive summary:

The acute toxicity of tert-butyl peroxypivalate to invertebrates was assessed according to OECD guideline 202, EU method C.2 and OPPTS 850.1010. Young Daphnia magna were exposed in an immobilisation test to aqueous test media containing the test item for 48 hours at a range of concentration. Because the concentration of the test item was expected to decrease more than 20 % from the nominal during the exposure period, the test was performed under semi-static conditions. The frequency of the water renewal periods was 24 hours. Based upon the results from the preliminary experiments, nominal concentrations of 4.3; 9.4; 20.7; 45.5 and 100.0 mg/L were investigated in the main study. The measured concentrations deviated more than 20 % from the nominal during the experiments therefore the geometric mean of the measured concentrations were calculated in order to determine exposure concentrations. The corresponding calculated geometric mean concentrations were the followings: 2.94, 6.51, 14.44, 31.76 and 64.65 mg/L. In this 48-hour acute toxicity test with Daphnia magna the 48 h EC50 value was determined as 6.99 mg/L, and the 48 h NOEC was determined to be 2.94 mg/L. The results are based on the measured geometric mean test item concentrations.

Description of key information

The acute toxicity of tert-butyl peroxypivalate to invertebrates was assessed according to OECD guideline 202, EU method C.2 and OPPTS 850.1010. The 48 h EC50 value was determined as 6.99 mg/L, and the 48 h NOEC was determined to be 2.94 mg/L. The results are based on the measured geometric mean test item concentrations.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

6.99 mg/L

Additional information

The acute toxicity of tert-butyl peroxypivalate to invertebrates was assessed according to OECD guideline 202, EU method C.2 and OPPTS 850.1010. Young Daphnia magna were exposed in an immobilisation test to aqueous test media containing the test item for 48 hours at a range of concentration. Because the concentration of the test item was expected to decrease more than 20 % from the nominal during the exposure period, the test was performed under semi-static conditions. The frequency of the water renewal periods was 24 hours. Based upon the results from the preliminary experiments, nominal concentrations of 4.3; 9.4; 20.7; 45.5 and 100.0 mg/L were investigated in the main study. The measured concentrations deviated more than 20 % from the nominal during the experiments therefore the geometric mean of the measured concentrations were calculated in order to determine exposure concentrations. The corresponding calculated geometric mean concentrations were the followings: 2.94, 6.51, 14.44, 31.76 and 64.65 mg/L. In this 48-hour acute toxicity test with Daphnia magna the 48 h EC50 value was determined as 6.99 mg/L, and the 48 h NOEC was determined to be 2.94 mg/L. The results are based on the measured geometric mean test item concentrations.