tert-butyl 2-ethylperoxyhexanoate

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:

1989-09-19 to 1989-12-23

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no analytics performed

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

1984

Deviations:

no

Principles of method if other than guideline:

NA

GLP compliance:

yes

Analytical monitoring:

not specified

Details on sampling:

NA

Vehicle:

yes

Details on test solutions:

As the test substance had a water solubility of 210 - 240 µg/mL, acetone was used as an organise solvent for the preparation of the stock solution in the preliminary test 2 -10 mg/L) and the definitive test. The stock solution in the definitive test contained 210 mg/L of test substance per litre of acetone. The selected test concentrations used in the definitive test (1.0 - 2.1 - 4.6 - 10.0 - 21.0 mg/L) were prepared by the addition of the respective amounts of stock solution to the diluting water. By using the acetonic stock solution an acetone concentration of 100 µL/L was obtained for each test concentration and control.

Test organisms (species):

Poecilia reticulata

Details on test organisms:

TEST ORGANISM
- Common name: Poecilia reticulata (guppy)
- Source: Rasbora/Aqualent
- Length at study initiation: ca. 2 cm
- Feeding during test: no

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

NA

Hardness:

231.4 mg/L CaCO3

Test temperature:

between 24 °C and 25 °C

pH:

8.2

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

1.0, 2.1, 4.6, 10.0, 21.0 mg test substance/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
As test vessels were used 2 L covered glass aquaria which contained 1 L of test medium. The loading of the test vessels was approximately 0.6 g biomass/L. The surviving fish were counted daily and dead fish removed immediately upon observation.

TEST MEDIUM / WATER PARAMETERS
The diluting water was a synthetic water, Dutch Standard Water, according to NPR 6507 (1980). The deionized water contained not more than 0.01 mg copper per litre and had a conductivity of less than 5 µS/cm. The TOC-content was not more than 2.0 mg/L.


OTHER TEST CONDITIONAS
- Photoperiod: 12 hours of ambient light per day

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

8.66 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL: 6.4 and 11.74 mg/L

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

2.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

After 96 hours no mortality was observed at concentrations up to and including 2.1 mg/L (NOEC, no observed effect concentration), whereas 21.0 mg/L produced 100% mortality within 72 hours. No changes in the behaviour or the appearance of the fish were observed.

The quality criteria of this test have been fulfilled: the mortality in the control was ≤ 10%, the oxygen concentration was > 60 % of the air saturation value throughout the test, except at the concentration of 9.7 mg/L where it was slightly lower.

Results with reference substance (positive control):

No positive control

Reported statistics and error estimates:

see below at " Any other information on results incl. tables"

Sublethal observations / clinical signs:

Mortality in definitive test:

mg test substance/ L	number of surviving animals
	0 h	24 h	48 h	72 h	96 h
control I	10	10	10	10	10
control II (acetone)	10	10	10	10	9
1.0	10	10	10	10	10
2.1	10	10	10	10	10
4.6	10	10	10	9	9
10.0	10	9	8	6	6
21.0	10	1	1	0
temperature °C	25	24	25	25	nd

nd: not determined

Statistical evaluation:

time (d)	LC50 (mg/L)	95% confidence limits
1	14.69	10.65 – 20.27
2	13.28	9.73 – 18.14
3	9.32	6.90 – 12.59
4	8.66	6.39 – 11.74

Validity criteria fulfilled:

yes

Conclusions:

The LC50 (96 h) as calculated was 8.66 mg/L with 95% confidence limits of 6.4 and 11.74 mg/L.

Executive summary:

Tert.-Butylperoxy-2-ethylhexanoat was tested in an acute toxicity test with Poecilia reticulata (guppy) under semi-static conditions in accordance with EEC method C.1 (1984) and OECD Test Guideline 203 (1984). Due to the poor solubility of the test substance in water the test concentrations were prepared using acetone as an organic solvent. Each test concentration contained 100 µL of acetone, as did one control. After 96 hours no mortality was observed at concentrations up to and including 2.1 mg/L (NOEC, no observed effect concentration), whereas 21.0 mg/L produced 100 % mortality within 72 hours. The LC 50 (96 h) as calculated was 8.66 mg/L with 95 % confidence limits of 6.4 mg/L and 11.74 mg/L.

No changes in the behaviour or the appearance of the fish were observed.

Description of key information

Tert.-Butylperoxy-2-ethylhexanoat was tested for acute toxicity to fish according to EU-method C.1 (1984) and OECD guideline 203 (1984). In this 96-hour semi-static acute toxicity test with Poecilia reticulata (guppy) the LC50 value was 8.66 mg/L. After 96 hours no mortality was observed at concentrations up to and including 2.1 mg/L (NOEC, no observed effect concentration), whereas 21.0 mg/L produced 100 % mortality within 72 hours.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

8.66 mg/L

Additional information

Tert.-Butylperoxy-2-ethylhexanoat was assessed in short-term toxicity to fish study, according to EU method C.1 and OECD guideline 203. Fish (Poecilia reticulata (guppy)) were exposed in a semi-static test to the test item for 96 hours at nominal concentrations of 1.0, 2.1, 4.6, 10.0 and 21 mg/L. The 96 h LC50 was determined to be 8.66 mg/L.