N-(2-ethylhexyl)-1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]naphthalen-2-amine

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:

7-12.1.2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

yes

Remarks:

see below

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

see below

Principles of method if other than guideline:

The study was performed without analytical determination of the test substance concentrations. For the analytical determination of the test substance concentration, no suitable analytical method was found. Therefore for all evaluations and results, nominal concentrations of the test substance were used.

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION OF TEST SOLUTION (especially for difficult test substances)
Since the test substance is poorly soluble in dilution water at concentrations needed for the test, saturated solutions of the test substance in dilution water were prepared by adding measured amounts of the test substance to the dilution water. The solutions were stirred for period of 72 hours on a shaft stirrer and consequently filtered through 0.45 μm filter. These solutions were used for testing.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain: Straus
- Source: In house
- Age at study initiation: Young daphnia <24 hours old
- Method of breeding: aperiodic parthenogenesis
- Feeding during test: No

ACCLIMATION
- Acclimation period: Not specified. Before the test, adult gravid females are separated into dilution water. Young daphnia born in the subsequent 24 hours are segregated to handling containers prior to transfer to test vessels.
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: A mixture of algae

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

Content of (Ca + Mg) in dilution water: 2.49 mmol/L

Test temperature:

20 ± 2 °C

pH:

7.9

Dissolved oxygen:

8.6 mg/L

Conductivity:

0.188 mS/m

Nominal and measured concentrations:

- Nominal concentrations: 100, 60, 40, 20 and 10 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Beakers
- Material, size, headspace, fill volume: 50 mL per beaker
- Aeration: No
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- Biomass loading rate: At least 2 mL of test solution per individual

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Standard dilution water was prepared just before the test by admixing 2.5 mL of stored solutions A, B, C and D in 1000 mL of deionised water. Solutions A to D contained 117.6 g CaCl2.2H2O, 49.3 g MgSO4.7H2O, 25.9 g NaHCO3 and 2.3 g KCl, respectively, each in 1 L of deionised water.
- Intervals of water quality measurement: The pH, temperature and dissolved oxygen were measured at the beginning and the end of the test.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: Natural variation of daily light and dark
- Light intensity: Natural

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
The daphnia immobilisation was observed after 24 and 48 hours.

VEHICLE CONTROL PERFORMED: No required

RANGE-FINDING STUDY
- Test concentrations: 100, 60, 40, 20 and 10 mg/L
- Results used to determine the conditions for the definitive study: No definitive study was carried out. Based on a lack of toxicity of the test substance in the preliminary test, the study was terminated. The concentration of 100 mg/L was included in the preliminary test with 20 daphnids; therefore the conditions of the limit test have been fulfilled.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

There was no immobilisation observed in any dose group throughout the study.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 48 hour EC50 = 0.78 mg/L (95 % confidence limit: 0.64 to 0.93 mg/L)
- Other: The immobilisation of test organisms by the reference substance obtained from the most recent testing facility reference was in the appropriate range. The sensitivity of test species and proficiency of the laboratory in test performance was therefore verified.

Reported statistics and error estimates:

No immobilisation was observed in the preliminary test. Therefore exact values of EC50 could not be calculated. The NOEC and EC100 values are identified by direct observation.

Validity criteria fulfilled:

yes

Remarks:

There was no immobilisation in the controls and the dissolved oxygen content remained above 3 mg/L.

Conclusions:

Under the conditions of this study, the 48 hour EC50 was determined to be >100 mg/L and the 48 hour NOEC was 100 mg/L.

Executive summary:

The test substance, Solvent Red 19E, was investigated for acute toxicity to Daphnia magna under GLP conditions.

The test was performed according to method C.2 – Daphnia sp. Acute Immobilisation Test, Council Regulation (EC) No. 440/2008, published in O.J. L 142, 2008 and OECD Test Guideline No 202, Daphnia sp., Acute Immobilisation Test, Adopted: April 13, 2004.

In a preliminary study, 20 daphnids per concentration were exposed the test material at nominal concentrations of 10, 20, 40, 60 and 100 mg/L under static conditions.

The nominal concentrations were used for all evaluations and results. The study was performed without analytical determination of test substance concentrations because no suitable analytical method was found.

Since the test substance is poorly soluble in dilution water at the concentrations needed for the test, saturated solutions of the test substance in dilution water were prepared by adding measured amounts of the test substance to the dilution water. The saturated solutions were stirred for a period of 72 hours on a shaft stirrer and consequently filtered through 0.45 μm filter.

As no toxicity of the test substance was found in preliminary test, the study was terminated. The concentration of 100 mg/L included in the preliminary test was performed using 20 daphnids per group; therefore the conditions of the limit test have been fulfilled. It was demonstrated that the EC50 is higher than this concentration, thus no further testing is required.

Under the conditions of this study, the 48 hour EC50 was determined to be >100 mg/L and the 48 hour NOEC was 100 mg/L. The 48 hour EC100 was >100 mg/L.

Description of key information

The 48 hour EC50 was determined to be >100 mg/L and the 48 hour NOEC was 100 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

The test substance, Solvent Red 19E, was investigated for acute toxicity to Daphnia magna under GLP conditions.

The test was performed according to method C.2 – Daphnia sp. Acute Immobilisation Test, Council Regulation (EC) No. 440/2008, published in O.J. L 142, 2008 and OECD Test Guideline No 202, Daphnia sp., Acute Immobilisation Test, Adopted: April 13, 2004.

In a preliminary study, 20 daphnids per concentration were exposed the test material at nominal concentrations of 10, 20, 40, 60 and 100 mg/L under static conditions.

The nominal concentrations were used for all evaluations and results. The study was performed without analytical determination of test substance concentrations because no suitable analytical method was found.

Since the test substance is poorly soluble in dilution water at the concentrations needed for the test, saturated solutions of the test substance in dilution water were prepared by adding measured amounts of the test substance to the dilution water. The saturated solutions were stirred for a period of 72 hours on a shaft stirrer and consequently filtered through 0.45 μm filter.

As no toxicity of the test substance was found in preliminary test, the study was terminated. The concentration of 100 mg/L included in the preliminary test was performed using 20 daphnids per group; therefore the conditions of the limit test have been fulfilled. It was demonstrated that the EC50 is higher than this concentration, thus no further testing is required.

Under the conditions of this study, the 48 hour EC50 was determined to be >100 mg/L and the 48 hour NOEC was 100 mg/L. The 48 hour EC100 was >100 mg/L.