2-Naphthalenol, heptyl-1-[2-[3-methyl-4-[2-(3-methylphenyl)diazenyl]phenyl]diazenyl]-

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:

from July 19 to August 9, 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:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Test guideline 4

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 (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction products of 3-Methylaniline with heptyl naphthalen-2-ol

Cas Number:

1619917-05-3

Molecular formula:

Not applicable (UVCB Substance)

IUPAC Name:

Reaction products of 3-Methylaniline with heptyl naphthalen-2-ol

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- batch No.of test material: 78-231-15
- Expiration date of the batch: December 01, 2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature, protected from light
- Stability in Solvent or Vehicle at RT: Stable in acetone

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

yes

Details on test solutions:

Dosage and concentrations

The test concentration was chosen in accordance with the results of a no GLP pre-test (range-finding test), whose relevant Raw Data were archived under the code of the present study.
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).

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, 20.0 μL of Stock Solvent Solution was introduced into 200.0 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. A strain of this species was supplied by MicroBioTests Inc., Belgium in December 2011 (batch number: DM290911).
Since that time, the clone has been bred in the laboratories of the Test Facility under conditions identical to those of the test, with regard to temperature, light and water quality (see below), so that no acclimation was needed prior to testing.
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.

Light intensity: 1200-1280 Lux
Light Regime: 16 hours light and 8 hours dark

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

140 - 250 mg/L as CaCO3

Test temperature:

20.0°C

pH:

7.30 – 7.57

Dissolved oxygen:

5.48 – 7.07 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), whose relevant Raw Data were archived under the code of the present study.
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).

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, 20.0 μL of Stock Solvent Solution was introduced into 200.0 mL of reconstituted water.
After preparation the test solution appeared light red, with no undissolved test item.

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).

Temperature:
The incubation temperature was continuously monitored during the course of the study by a PT100 probe installed in the environmental test chamber. It was in the range 19.9 – 20.1°C with a mean value of 20.0°C and a standard deviation of 0.02°C. The temperature range provided by OECD guideline 202, 2004 is 20 ± 2°C. The temperature values during the test were within the provided range and did not vary more than 1°C during the test period.

Prior to the study start, the test water was aerated until oxygen saturation was reached. During the test period, the test water was not aerated.

The dissolved oxygen concentration and the pH were determined in the negative control, in the solvent control and in test item solution at the start and at the end of the test.
At the test start, in fresh test media, oxygen concentration and pH were measured sampling an aliquot immediately after test solution preparation, before pouring it in the test glass beakers.
After 48 hours, oxygen concentration and pH were measured after removing the daphnids from the test glass beakers containing spent solutions.

The dissolved oxygen concentration in the negative control, solvent control and in the test item solution was always higher than 5.47 mg/L (Table 1) according to OECD guideline 202, 2004 that provides a minimum oxygen concentration of 3.0 mg/L.

The pH of the fresh test media was 7.46 for negative control, 7.34 for solvent control and 7.57 for the only test item solution at 1.0 mg/L. The pH did not vary by more than 1.5 unit during the test period, as required in the mentioned guideline

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of test item RED 2596 was tested on Daphnia magna under static conditions.
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 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

The highest tested concentration of 1.0 mg/L corresponding to the maximum solubility of the test item obtained in the test medium.