Dilauroyl 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:

18 October 1989 - 11 November 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The test was performed according to standard methods and was compliant with GLP. The substance identity was sufficiently described and the test satisfied validity criteria. Although no analysis were performed and though results are based on nominal concentration, the test was conducted above the limit of solubility of the test substance as seen by the floating of flakes at the surface of each test vessel. Thus it is believed that the fish were always exposed to a concentration corrisponding to the water solubility of the test substance. Only a limit test was performed at 1000 mg/l because lower concentrations in a range-finding test were tested using acetone as solvent without significant improvement in solubilisation. No mortalities were reported in the range finding test nor the limit test. Consequently, the data are reliable with the restriction that chemical analysis were not performed and thus the water solubility value of the test substance is used to determine the LC50.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

No measurements of tested concentrations

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

yes

Remarks:

No measurements of tested concentrations

Principles of method if other than guideline:

No measurements of tested concentrations

GLP compliance:

yes

Remarks:

Statement of 1990-05-16

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
- solubility: not soluble at test concentrations

Analytical monitoring:

no

Details on sampling:

The surviving fish were counted daily and dead fish were removed immediately upon observation.

Vehicle:

yes

Details on test solutions:

The test was performed as a semi-static test with the solution being renewed after 48h.
The diluting water was a synthetic water, Dutch Standard water, according to NPR 6507 (1980), having a pH of approximately 8.2 and a hardness of 13° dH, containing per litre of deionized water: 100 mg of NaHCO3/l; 20 mg of KHCO3/l; 200 mg of CaCl2.2H2O/l and 180 mg of MgSO4.7H2O/l. 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.
In the range-finding test (which was not performed in compliance with the GLP guidelines) considering the poor solubility of the test substance in water, the concentrations of 1.0 and 10.0 mg/l were prepared by using an acetonic stock solution. However, also in acetone the test substance was not completely dissolved and after addition of the test substance to the diluting water the test substance precipitated. Therefore, the concentration of 1000 mg/l was prepared by the direct addition of the test substance to the diluting water without addition of acetone.
For the definitive test, the test medium was prepared by the direct addition of 1000 mg of test substance to 1 litre of diluting water either. The solutions were stirred for 24h at room temperature before the fish were introduced. During the test flakes of the test substance floated on the surface of the test medium.

Test organisms (species):

Poecilia reticulata

Details on test organisms:

In contravention to the study plan they were obtained from the IOB (Instituut voor Onderzoek van Bestrijdingsmiddelen, Wageningen, The Netherlands). Before being used in the test, the fish were held in stock for about 4 weeks in the Akzo Research Laboratories Arnhem, dept. CRL, in conformity with
Standard Operating Procedures SOP CRL T9 and 42 to determine the acceptability of the batch. The size of the fish was approximately 2 cm.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

None

Hardness:

13 dH

Test temperature:

22-26 C

pH:

Measurements of the pH were carried out on days 0, 2 and 4 and results are presented in the Table 1 of the "Any other information on materials and methods incl. tables" field below.

Dissolved oxygen:

Measurements of the oxygen concentrations were carried out on days 2 and 4 and results are presented in the Table 1 of the "Any other information on materials and methods incl. tables" field below.

Salinity:

Not applicable

Nominal and measured concentrations:

- Nominal, 1, 10, 1000 mg/L in the range-finding test.
- Nominal, 1000 mg/L in the definitive test.

Details on test conditions:

In contravention to the study plan the temperature was kept between 22°C and 26°C, and the light regime was 12 hours of ambient light per day. No food was given during the test and no aeration of the test mediumwas performed. The duration of the test was 96 hours. 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 test was performed in duplicate. 10 fishes were tested per test concentration and control.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(test concentration up to water solubility limit)

Basis for effect:

mortality (fish)

Remarks on result:

other: 99,9% CL

Details on results:

The fish survived for 96 hours in a saturated solution containing 1000 mg of dilauroyl peroxide/l. Binomial theory dictates that when 10 fish are used showing zero % mortality, there is a 99,9% confidence that the LC50 is greater than 1000 mg/l. However, given the fact that during the test flakes of the test substance floated on the surface of the test medium, the LC50 value is set to be equal to the water solubility of the test substance.
No other effects such as deviations in the behaviour or appearance of the fish were observed.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Not applicable

Sublethal observations / clinical signs:

Table 2 Results from range finding test:

[Test substance] (mg/L)	Number of surviving animals
	0h	24h	48h	72h	96h
Control	5	5	5	5	Nd
1	5	5	5	5	5
10	5	5	5	5	Nd
1000	5	5	5	Nd	5

Nd: not determined

2) results from definitve study:

[Test substance] (mg/L)	Number of surviving animals
	0h	24h	48h	72h	96h
Control	10	10	10	10	10
1000	10	10	10	10	10
1000	10	10	10	10	10
Temperature C	22	22	23	23	26

Validity criteria fulfilled:

yes

Remarks:

stability concluded on additional information

Conclusions:

The acute toxicity of dilauroyl peroxide to the guppy was determined and resulted in a LC50>0.3 mg/L corresponding to its water solubility. The study meets all criteria and therefore is considered valid. However the endpoint determined is based on nominal concentrations since no analysis was performed. The test substance proved not to be soluble at the tested concentration and flakes were observed.

Executive summary:

The 96h- acute toxicity of Dilauroyl peroxide was tested in a semi-static test on Poecilia reticulata (guppy) in accordance with EEC method C.1(1984) and OECD Test Guideline 203 (1984). Two tests were performed. A range-finding test using acetone as a solvent tested the acute toxicity at 1, 10, and 1000 mg/L of the test substance. The definitive test was conducting using one concentration, 1000 mg/L prepared by direct addition into dilution water and stirring for 24h. During the test flakes were floating at the surface of test solutions drawing evidence that saturation limit was achieved. No chemical analysis were performed and therefore results are based on nominal concentrations. About test condition, hardness was 13 dH, temperature was 22 -26°C, pH and dissolved oxygen were measured on days 0, 2 and 4. Ten fish were tested in the definitive test with duplicated test groups and a control. No mortalities were observed while all validity criteria were fulfilled.

Therefore, the acute toxicity dilauroyl peroxide on guppies was LC50 > 0.3 mg/L corresponding to the water solubility of the test substance. At this concentration no sub lethal effects were observed.

Description of key information

96 h LC50 WAF test on fish with no effects found up to 1000 mg/L

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1 000 mg/L

Additional information

One reliable GLP study on Poecilia reticulate following international guidelines is available (Mark and Mewsen, 1990). A limit test at 1000 mg/L was prepared by direct dilution and stirring for 24h. visual observation of the test solution gave evidence of saturation limit was achieved. After 96 hours, no mortality nor sub-lethal effects were observed. No chemical analysis were performed and final result was based on the known limit of solubility by the time of the test. It was concluded the 96h-LC50 > 0.3 mg/L and a 96 h LR50 >1000.