2-Naphthalenol, 1-[2-[2-ethyl-4-[2-(2-ethylphenyl)diazenyl]phenyl]diazenyl]-, ar-heptyl derivs.

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: OECD Series on Testing and Assessment No 23 - Guidance Document On Aquatic Toxicity Testing Of Difficult Substances And Mixtures ENV/JM/MONO(2000)6.

GLP compliance:

yes

Test material

Test material information

1

Reference substance name:

Reaction products of 2-Ethylaniline with heptyl naphthalen-2-ol

Cas Number:

1401000-07-4

Molecular formula:

Not applicable (UVCB Substance)

IUPAC Name:

Reaction products of 2-Ethylaniline with heptyl naphthalen-2-ol

Test material form:

solid

Specific details on test material used for the study:

Batch number: 80-47-16

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

yes

Remarks:

acetone

Details on test solutions:

Since the test item is insoluble in water, it was added to the reconstituted water by the means of a solvent vehicle (acetone). Therefore a solvent control (reconstituted water whit the same concentration of acetone used as carrier) was added in order to verify the absence of toxic effect due to the solvent; moreover a negative control (reconstituted water without test item) was prepared.

The test medium was prepared as follows: the day of the test start, a 10000.0 mg/L Stock Solvent Solution was prepared by direct weighing 0.0500 g of test item into 5.0 mL of acetone.
The resulting solution was observed to be dark red, with no undissolved test item.

In order to prepare the test item concentration of 1.0 mg/L, 25.0 μL of Stock Solvent Solution was introduced into 250.0 mL of reconstituted water.
After preparation the test solution appeared light red, with no undissolved test item.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

The study was performed on the freshwater crustacean Daphnia magna Straus.
It was daily fed with a fixed amount of the laboratory cultured green algae Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) and with a suspension of the yeast Saccharomyces cerevisiae.

At the test start the organisms used in the test were less than 24 hours old and were not first brood progeny.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

20.0°C

pH:

6.56 – 7.73

Dissolved oxygen:

6.50 – 7.81 mg O2/L

Nominal and measured concentrations:

The test concentration was chosen in accordance with the results of a no GLP pre-test (range-finding test).
The main final test included only one nominal test item concentration 1.0 mg/L, corresponding to the maximum solubility of the test item in the test medium.
Since the percentage of immobilisation at the test concentration not exceed 10 % at the test end, a full test was not necessary (according to the OECD 202).

Details on test conditions:

The test was performed in glass beakers filled with 40 mL of test medium. The test vessels were covered with glass plates to reduce the loss of water and to avoid dust entry into test solutions.
The test vessels were labelled with the internal study number and all necessary additional information to ensure unmistakable identification.

For the test concentration, for the negative control and for the solvent control, group of 20 daphnids were used divided into four replicates of five daphnids each. The daphnids were randomly distributed to the test vessels at test initiation. The daphnids loading rate was about 8 mL per one daphnid (5 daphnids for 40 mL, according to OECD guideline 202, 2004).

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 4

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 5

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 6

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 7

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 8

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of test item RED 2735 was tested on Daphnia magna under static conditions.
The EC0, the EC100, the EC50 value and the NOEC at 24 and 48 hours were assessed.

Results, calculated in terms of nominal test item concentration, were as follows:

Time (h) EC0 (mg/L) EC100(mg/L) EC50(mg/L) NOEC(mg/L)
24 1.0 >1.0 >1.0 1.0
48 <1.0 >1.0 >1.0 1.0

Therefore the EC50 values at 24 and 48 hours are higher then the maximun water solubility of the test item (< 0.1 mg/l).

Executive summary:

A limit test at only one concentration, 1.0 mg test item/L was performed to evaluate the effect of the test item RED 2735 on Daphnia magna under static conditions.

 

The daphnids were observed for immobility after 24 and 48 hours of exposure.

In the negative control and in the solvent control respectively 5% and 0% of immobilization was observed and no daphnid was trapped on the test water surface or showed other signs of disease or stress. These values comply with the validity criteria of the test, that provides a maximum immobilization or a maximum number of daphnids showing distress signs of 10% in the negative control or in the solvent control at the end of the test.

 

The obtained experimental results allowed to determine the EC₀, EC₁₀₀, EC₅₀and NOEC values at 24 and 48 h.

 

EC₀, EC₁₀₀, EC₅₀and NOEC, expressed in terms of nominal test item concentration, were as follows:

 

Time (h)	EC0 (mg/L)	EC100 (mg/L)	EC50 (mg/L)	NOEC (mg/L)
24	1.0	>1.0	>1.0	1.0
48	< 1.0	>1.0	>1.0	1.0

EC50 values at 24 and 48 hours are higher then the maximun water solubility of the test item (< 0.1 mg/l).