2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone

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:

11 March 2018 to 20 April 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Reliable experimental study following OECD 202 guidelines (2004) and EC No. 440/2008 Method C.2 adopted 2008 and GLP standards.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

The test was carried out using first instar Daphnia magna derived from in-house laboratory cultures.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

20°C to 21 °C

pH:

7.8 to 7.9

Dissolved oxygen:

8.9 to 9.4 mg O2/L

Nominal and measured concentrations:

Preliminary solubility work conducted indicated that it was not possible to obtain a testable solution of the test item using traditional methods of preparation such as ultrasonication and high shear mixing. A preliminary media preparation trial indicated that a saturated solution method of preparation was appropriate for this test item. The definitive test was conducted at a concentration of 100% v/v saturated solution which corresponds to an initial loading rate 10 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate was used as the reference item at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % v/v saturated solution.

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

100% v/v saturated solution prepared from a test solution with a loading rate of 10 mg/L.

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

Test solution prepared with a loading rate of 10 mg/L resulting in a 100% v/v saturation solution.

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % v/v saturated solution.

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

100% v/v saturated solution prepared from a test solution with a loading rate of 10 mg/L.

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

Test solution prepared with a loading rate of 10 mg/L resulting in a 100% v/v saturation solution.

Details on results:

Results were based on the nominal test concentration of 100% v/v saturation solution which is equivalent to an initial nominal loading level of 10 mg/L.

Results with reference substance (positive control):

The results from the positive control with potassium dichromate were within the normal range for this reference item.

Validity criteria fulfilled:

yes

Remarks:

The test was considered valid since none of the control daphnids showed immobilisation or other signs of disease or stress and the oxygen concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.

Conclusions:

The test substance did not induce acute immobilisation of Daphnia magna at the limit test after 48 h of exposure; therefore, there were not toxic effects at saturation. The median effects concentration was based on the nominal test concentration of 100% v/v saturated solution which was prepared from an initial test solution with a nominal loading rate of 10 mg/L. The median effects concentration was reported both as 48-h EC50 > 100% v/v saturated solution and 48-h EL50 >10 mg/l. The no effects concentration was reported both as 48-h NOEC of 100 % v/v saturated solution and 48-h NOELR of 10 mg/L.

Description of key information

EL50 (48 h) > 10 mg/L (nominal loading rate)

Additional information

The acute toxicity of the substance to aquatic invertebrates was tested in a guideline study following OECD Guideline 202. The test was set up as a static limit test with a nominal test substance concentration of 10 mg/L (initial loading rate). The effects concentrations were based on the nominal test concentration of 100% v/v saturated solution which was prepared from an initial test solution with a nominal loading rate of 10 mg/L. Daphnia magna was exposed to the test substance for 48 hours. Immobilisation of Daphnids was not observed. The reported EL50(48 h) was >10 mg/L (nominal loading rate).