tert-butyl peroxypivalate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-05-27 to 1991-07-12

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Remarks:

GLP study; OECD and EU guidelines were followed with restrictions. Deficiences: no analytics were performed.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1989

Deviations:

yes

Remarks:

no analytics were performed

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

1989

Deviations:

yes

Remarks:

no analytics were performed

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: preparation of stock solution (1g/L): For the preparation of the solution approximately 50 mL of deionized water was added to the test substance, and after stirring for 5 minutes at room temperature, the mixture was ultrasonically treated. Thereafter, deionized water was added up to a final volume of 1000 mL.
- Eluate: water
- Controls: yes

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Brachydanio rerio (zebrafish)
- Source: a well-known local aquarium retailer (Rasbora, Veenendaal)
- Length at study initiation: 2 - 3 cm
- Weight at study initiation: 0.3 g
- Feeding during test: the fish were fed one to three times each day (6 days a week), the last feeding taking place about 24 hours before the test was started

ACCLIMATION
- Acclimation period: 12 days
- Acclimation conditions: same

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

11.7 °dH

Test temperature:

23.1 to 24 °C

pH:

7.7 to 8.3

Dissolved oxygen:

lowest oxygen concentration: 6.9 mg/L

Nominal and measured concentrations:

- nominal concentration: 7, 13.3, 25.3, 48, 91.2 mg/L
- no measured concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel: 5 L glass aquaris containing 3 L of test medium
- Type: closed (covered with a glass plate during the test)
- No. of organisms per vessel: 7
- Biomass loading rate: approximately 0.7 g of biomass/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic water
- Metals: not more than 10 µg of copper per litre
- Conductivity: less than 5 µS/cm
- Culture medium different from test medium: yes
- Intervals of water quality measurement: oxygen concentrations and pH-values were measured on day 0, 1, 2, 3,4

OTHER TEST CONDITIONS
- Photoperiod: 12 hours of ambient light per day
- Light intensity: fluorescent tubes

EFFECT PARAMETERS MEASURED : mortality

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: One preliminary test was perfeormed under static conditions with following concentration: 1, 10, 100 mg/L.
- Results used to determine the conditions for the definitive study: No mortality was observed at concentration up to and including 10 mg/L during 96 hours and 100 % mortality was observed within 1 hour at 100 mg/L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

8.65 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Value adjusted due to rapid hydrolysis.

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

18.85 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Value adjusted due to rapid hydrolysis.

Details on results:

The highest concentration causing no mortality (no observed effect concentration, NOEC) after 96 hours was estimated to be 8.65 mg/L, whereas 100 % mortality was produced within 18 hours at about 31.2 mg/L. The LC50 (96 h) was estimated to be 18.85 mg/L.

Results with reference substance (positive control):

LC 50 (96 h) was 125 mg/L (95 % confidence limits = 97.5 - 160)

Reported statistics and error estimates:

The LC50 was calculated with a programme using both the trimmed Spearman-Kärber method and binomial test method.

Validity criteria fulfilled:

yes

Conclusions:

The highest concentration causing no mortality (no observed effect concentration, NOEC) after 96 hours was estimated to be 8.65 mg/L, whereas 100 % mortality was produced within 18 hours at about 31.2 mg/L. The LC50 (96 h) was estimated to be 18.85 mg/L.

Executive summary:

Tert-butyl peroxypivalate was tested in an acute toxicity test with Brachydanio rerio (zebra fish) under semi-static conditions according to EU method C.1 and OECD guideline no. 203. No chemical analyses of the test substance dissolved in the test media were performed. Therefore, all concentrations referred to in the report are nominal concentrations. The highest concentration causing no mortality (no observed effect concentration, NOEC) after 96 hours amounted to 13.3 mg/L, whereas 100 % mortality was produced within 18 hours at 48 mg/L. The LC50 (96 h) was calculated to be 29.0 mg/L with 95 % confidence limits of 23.3 and 36.1 mg/L. At 25.3 mg/L and higher concentrations reduced activity could be observed starting after 1 - 3 hours and lasting throughout the test. At 48 mg/L and 91.2 mg/L disturbances and loss of equilibrium were observed before the fish died.

 

As mentioned before these are the results based on nominal concentrations as the test has been performed without chemical analyses. However, based on the hydrolytical instability of the substance (see section 5.1.2 for details), this degradation will lower the effect concentrations NOEC and LC50 and has to be taken into consideration. Since the two other acute toxicity studies performed with Daphnia (see IUCLID5 section 6.1.3) and Algae (see IUCLID5 section 6.1.5.) have been performed including chemical analyses, the recovery rates on measured concentrations obtained in these studies have been used as reference. As a worst case approach a concentration of 65 % of the nominal value was assessed which is equal to the lowest concentration measured in the acute test with Daphnia magna. Application of this 65 % recovery rate to the nominal effect concentrations determined in the fish study leads to a reduction of the NOEC (96 h) to ca. 8.65 mg/L and LC50 (96 h) to ca. 18.85 mg/L. As compared to the acute toxicity studies with Daphnia and Algae the fish is far from being the most sensitive species in this aquatic toxicity studies. Thus, even though the analytical investigations are missing in the study performed with Brachydanio rerio in 1991, due to animal welfare reasons a repetition of this vertebrate study is not foreseen as it is not reasonable.

Description of key information

The highest concentration causing no mortality (no observed effect concentration, NOEC) after 96 hours was estimated to be 8.65 mg/L, whereas 100 % mortality was produced within 18 hours at about 31.2 mg/L. The LC50 (96 h) was estimated to be 18.85 mg/L. The waiver included as separate endpoint study record further gives reference to an assessment made on altogether 28 organic peroxides demonstrating that among the three trophic levels, the alga proved to be the most sensitive species under short-term conditions to organic peroxides.
In consequence, a new test on short-term toxicity to fish is not required.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

18.85 mg/L

Additional information

Tert-butyl peroxypivalate was tested in an acute toxicity test with Brachydanio rerio (zebra fish) under semi-static conditions according to EU method C.1 and OECD guideline no. 203. No chemical analyses of the test substance dissolved in the test media were performed. Therefore, all concentrations referred to in the report are nominal concentrations. The highest concentration causing no mortality (no observed effect concentration, NOEC) after 96 hours amounted to 13.3 mg/L, whereas 100 % mortality was produced within 18 hours at 48 mg/L. The LC50 (96 h) was calculated to be 29.0 mg/L with 95 % confidence limits of 23.3 and 36.1 mg/L. At 25.3 mg/L and higher concentrations reduced activity could be observed starting after 1-3 hours and lasting throughout the test. At 48 mg/L and 91.2 mg/L disturbances and loss of equilibrium were observed before the fish died.

As mentioned before these are the results based on nominal concentrations as the test has been performed without chemical analyses. However, based on the hydrolytical instability of the substance (see section 5.1.2 for details), this degradation will lower the effect concentrations NOEC and LC50 and has to be taken into consideration. Since the two other acute toxicity studies performed with Daphnia (see IUCLID5 section 6.1.3) and Algae (see IUCLID5 section 6.1.5.) have been performed including chemical analyses, the recovery rates on measured concentrations obtained in these studies have been used as reference. As a worst case approach a concentration of 65 % of the nominal value was assessed which is equal to the lowest concentration measured in the acute test with Daphnia magna. Application of this 65 % recovery rate to the nominal effect concentrations determined in the fish study leads to a reduction of the NOEC (96 h) to ca. 8.65 mg/L and LC50 (96 h) to ca. 18.85 mg/L.

As compared to the acute toxicity studies with Daphnia and Algae the fish is far from being the most sensitive species in this aquatic toxicity studies.

 

This is further supported by an assessment on the most sensitive species for organic peroxides, which has been made by the member of the organic peroxides consortium and which is referred to in a waiver additionally added as a separate endpoint study record in this section.

The most critical acute data available for each trophic level (aquatic invertebrates, fish and algae) for altogether 28 organic peroxides belonging to the group of organic peroxides registered under REACH had been compiled in order to determine the species sensitivity for the organic peroxides. In conclusion, among the three trophic levels, the alga proved to be the most sensitive species under short-term conditions to organic peroxides (for details see the organic peroxides consortium’s position paper “Adaption of the Assessment Factor for Aquatic PNEC Derivation for Organic Peroxides - Low acute to chronic ratio” (author: CEHTRA, Report no. CFR-12.012, cf. attachment in IUCLID section 13). Thus, even though the analytical investigations are missing in the short-term toxicity test to fish, due to animal welfare reasons a repetition of this vertebrate study is not foreseen as not reasonable.

Thus, even though the analytical investigations are missing the test available is considered sufficient to evaluate the short-term toxicity to fish. Further, due to animal welfare reasons a repetition of this vertebrate study is not foreseen as not reasonable.