Cyclohexylidenebis[tert-butyl] peroxide

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:

2006-03-07 to 2006-07-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

adopted 17 July 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

Directive 92/69/CEE

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
As the test item is poorly soluble in aqueous media, two saturated WAF solutions at 10 mg/L and 100 mg/L were prepared by stirring respectively 500 mg (602 µL) and 50 mg (60.1 µL) of the test item in 5 litres of dilution water at 23 °C for 72 hours before the beginning of the test. At the end of this stirring period, which corresponded to the day on which the test was started, the excess substance item was eliminated by decantation and filtration through a MF-Milipore membrane filter Mixed cellulose esters 0.45 µm HAWP 04700. WAF solutions were renewed using the same method on each day after 24, 48 and 72 hours; these solutions were prepared according to the same scheme, but with only 23 h of stirring period.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Source: HB Developpement (69490 St Forgeux)
- Batch no.: 06/Br/02/1
- Age at study initiation: one month
- Length at study initiation: 3.2 ± 0.15 cm
- Acclimatization period: The fish were placed under test conditions one month before the beginning of the test.
- Other: Mortality in the aquarium containing the batch of fish used for the tests was less than 5 % (observed mortality: < 1 %) over the seven days preceding the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

23 ± 1 °C

pH:

7.42 to 8.05

Dissolved oxygen:

71 to 10 % air saturation

Nominal and measured concentrations:

- nominal loadings of 10 and 100 mg/L of test item (peroxide in isododecane) correspond to loadings of 5.06 and 50.6 mg/L (actual measured concentration of peroxide)
- Arimetic mean of geometric means for nominal loadings of 10 and 100 mg/L (0-96 h): 0.47 and 0.64 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 2.5 litres reactors
- Renewal rate of test solution: renewed every 24 hours
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: osmotically filtered water was used to prepare the dilution water
- Intervals of water quality measurement: Every day, the dissolved oxygen and the pH were measured at each concentration and in control vessel for fresh and 24 h old solutions.

OTHER TEST CONDITIONS
- Photoperiod: 12 hours of darkness per 24 h
- Light intensity: approximately 400 and 800 lux

EFFECT PARAMETERS MEASURED
The fish were examined after 3 hours and at intervals not exceeding 24 hours, and the dead fish were counted and removed from the vessels.

TEST CONCENTRATIONS
Considering the results (daphnids and algae results) that in both cases the EC50 are over the solubility limit and the results of stability test showing the solubility limit, it was decided to perform the test at 10 and 100 mg/L as nominal initial loadings.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

> 0.64 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: based on actual measured concentration of the peroxide

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 0.64 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: based on actual measured concentration of the peroxide

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

> 0.64 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: based on actual measured concentration of the peroxide

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.64 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: based on actual measured concentration of the peroxide

Duration:

24 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: based on nominal test item concentration

Duration:

48 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: based on nominal test item concentration

Duration:

72 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: based on nominal test item concentration

Key result

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: based on nominal test item concentration

Details on results:

LC50 is higher than the limit of solubility that appears to be here 0.64 mg/L for the peroxide and corresponds to a LL50 that is higher than 100 mg/L for the test item.

Mortality of the fish in the control vessels:
The mortality after 96 h in control series is 0 %. Quality criteria of the study (mortality <= 10 % at the end of the test) are met.

Results with reference substance (positive control):

The results of the last test carried out on 08/06/06, were a CL50-24 h of 250 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

The 96 h-LC50 and 96 h-LL50 values were determined to be > 0.64 mg/L and > 100 mg/L.

Executive summary:

The purpose of this study was to evaluate the influence of the test item on Danio rerio in accordance with OECD guideline no. 203 and EU method C.1. Young fish were exposed in an acute toxicity test to aqueous test media containing the test item for 96 hours at a range of concentration (10 and 100 mg/L (nominal)) under semi-static conditions.The frequency of the renewal periods was 24 hours. The measured concentrations deviated more than 20 % from the nominal during the experiment therefore the geometric mean of the measured concentrations were calculated in order to determine exposure concentrations. The calculated geometric mean concentrations were 0.47 and 0.64 mg/L. The 96 h-LC50 and 96 h-LL50 values were determined to be > 0.64 mg/L and > 100 mg/L.

Description of key information

The 96 h-LC50 and 96 h-LL50 values were determined to be > 0.64 mg/L and > 100 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

> 0.64 mg/L

Additional information

The purpose of this study was to evaluate the influence of the test item on Danio rerio in accordance with OECD guideline no. 203 and EU method C.1. Young fish were exposed in an acute toxicity test to aqueous test media containing the test item for 96 hours at a range of concentration (10 and 100 mg/L (nominal)) under semi-static conditions.The frequency of the renewal periods was 24 hours. The measured concentrations deviated more than 20 % from the nominal during the experiment therefore the geometric mean of the measured concentrations were calculated in order to determine exposure concentrations. The calculated geometric mean concentrations were 0.47 and 0.64 mg/L. No lethality was observed. The 96 h-LC50 and 96 h-LL50 values were determined to be > 0.64 mg/L and > 100 mg/L.