1-phenylazo-2-naphthol

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:

28 July 2003 - 07 October 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Data is from experimental study report.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Specific details on test material used for the study:

- Name of test material: 1-phenylazo-2-naphthol (Sudan Orange 220)
- Molecular formula: C16 H12 N2 O
- Molecular weight: 248.284 g/mol
- Smiles notation: c12c(\N=N\c3ccccc3)c(ccc1cccc2)O
- InChl: 1S/C16H12N2O/c19-15-11-10-12-6-4-5-9-14(12)16(15)18-17-13-7-2-1-3-8-13/h1-11,19H/b18-17+
- Substance type: Organic
- Physical state: Solid

Analytical monitoring:

yes

Remarks:

The identity of the test item was confirmed by IR-spectroscopy .

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:The test substance was stirred in M4 medium for about 20 hours at 20 ± 2°C. Undissolved test substance was removed by filtration with a membrane filter.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Water
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): Undissolved test substance was removed by filtration with a membrane filter

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: straus
- Source: nstitut National de Recherche Chimique Appliquée, France, in 1978 .
- Age of parental stock (mean and range, SD): Age of the animals at the begin of exposition:2 - 24 h (starting with the 3rd breed of parent animals)
Age of stock animals: 2-4 weeks
- Feeding during test: no feeding during test

Test type:

static

Water media type:

freshwater

Remarks:

synthetic fresh water

Limit test:

yes

Total exposure duration:

48 h

Hardness:

2.20 - 3.20 mmol/l

Test temperature:

18 - 22 °C (max. temperature difference 2°C )

pH:

7.5-8.5

Conductivity:

550 - 650 µS/cm

Nominal and measured concentrations:

Nominal : 100 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel:Test tubes (glass) with flat bottom (nominal volume 20 ml)
- Material, size, headspace, fill volume: 20ml
- Aeration: Yes
- No. of organisms per vessel: 20
- No. of vessels per control (replicates):4
- No. of vessels per vehicle control (replicates):4
:
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:synthetic fresh water was used for culture,After preparation the M4 medium is aerated for approximately 24 h until saturation with oxygen is reached .
- Alkalinity:1.00 mmol/I at pH 4.3
- Ca/mg ratio:2.20 - 3.20 mmol/l
- Conductivity:550 - 650 µS/cm

OTHER TEST CONDITIONS
- Adjustment of pH: 7.5-8.5
- Photoperiod:Artificial light, type warm white (OSRAM L58 W31) day:night rhythm = 16 : 8 h
- Light intensity:About 1- 8 NE/(mZ•s) at a wave length of 400 - 750 nm

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Swimming ability of the test animals at 24 and 48 hrs

RANGE-FINDING STUDY
- Test concentrations:
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

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

Results with reference substance (positive control):

The EC50(24h) of the control substance potassium dichromate (non-GLP) was 1,33 mg/I

Reported statistics and error estimates:

Due to the results of the test no statistical evaluation of the data was performed .

Concentration control analyses

The test was performed without concentration control analyses, because the tested concentration was below the detection limit . The test item is stable in test water over a period of 72 hours

Validity criteria fulfilled:

yes

Remarks:

• In the control the immobilization was less than equal 10% • In the control no daphnids were captured in a surface film. • The 02-concentration was > 3 mg/I in all tested replicates. • The EC50(24h) of the control substance was 1.33 mg/I

Conclusions:

From the experiment, the EC50 value for 1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9) for daphnia magna was determined to be >100mg/l.
Based on result, the1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9) was considered non toxic to aquatic invertebrates and considered to be not classified as per the CLP regulation.

Executive summary:

Determination of the acute effect on the swimming ability of the Daphnia magna straus was performed using OECD guideline 202. Limit test was conducted at 100 mg/l concentrations. The test substance was suspended in water. The daphnids were exposed to various concentrations of the test substance and compared to a control. Synthetic fresh water was used for culture and test purposes. M4 medium was used and aerated for approximately 24 h until saturation with oxygen is reached. Proper test conditions were maintained. No feeding during test was done. Measurement of temperature continuously during the whole test period in a separate vessel close the test vessels and measurement of pH and oxygen after 0h in an additional replicate without daphnids and after 48h in replicate 1 of each tested concentration were taken.The test substance was stirred in M4 medium for about 20 hours at 20 ± 2°C. Undissolved test substance was removed by filtration with a membrane filter. The test is fulfilled the validity criteria.

From the experiment, it can be seen that, the EC 50 value for 1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9) for daphnia magna was determined to be >100mg/l.

Based on result, the 1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9) was considered to be non toxic to aquatic invertebrates and considered to be not classified as per the CLP regulation.

Description of key information

Determination of the acute effect on the swimming ability of the Daphnia magna straus was performed using OECD guideline 202. Limit test was conducted at 100 mg/l concentrations. The test substance was suspended in water. The daphnids were exposed to various concentrations of the test substance and compared to a control. Synthetic fresh water was used for culture and test purposes. M4 medium was used and aerated for approximately 24 h until saturation with oxygen is reached. Proper test conditions were maintained. No feeding during test was done. Measurement of temperature continuously during the whole test period in a separate vessel close the test vessels and measurement of pH and oxygen after 0h in an additional replicate without daphnids and after 48h in replicate 1 of each tested concentration were taken.The test substance was stirred in M4 medium for about 20 hours at 20 ± 2°C. Undissolved test substance was removed by filtration with a membrane filter. The test is fulfilled the validity criteria.

From the experiment, it can be seen that, the EC 50 value for1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9)for daphnia magna was determined to be >100mg/l.

Based on result, the1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9)was considered to be non toxic to aquatic invertebrates and considered to be not classified as per the CLP regulation.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

Various experimental studies for toxicity to aquatic invertebrate with the target substance 1-phenylazo-2-naphthol (CAS No. 842-07-9) were summarized as follows:

In the first experimental study conducted by BASF () determination of the acute effect on the swimming ability of the Daphnia magna straus was performed using OECD guideline 202. Limit test was conducted at 100 mg/l concentrations. The test substance was suspended in water. The daphnids were exposed to various concentrations of the test substance and compared to a control. Synthetic fresh water was used for culture and test purposes. M4 medium was used and aerated for approximately 24 h until saturation with oxygen is reached. Proper test conditions were maintained. No feeding during test was done. Measurement of temperature continuously during the whole test period in a separate vessel close the test vessels and measurement of pH and oxygen after 0h in an additional replicate without daphnids and after 48h in replicate 1 of each tested concentration were taken.The test substance was stirred in M4 medium for about 20 hours at 20 ± 2°C. Undissolved test substance was removed by filtration with a membrane filter. The test is fulfilled the validity criteria. From the experiment, it can be seen that, the EC 50 value for 1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9) for daphnia magna was determined to be >100mg/l. Based on result, the 1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9) was considered to be non toxic to aquatic invertebrates and considered to be not classified as per the CLP regulation.  

Moreover, in the second experimental study conducted by SSS (2017), determination of the inhibition of the mobility of daphnids was carried out with the substance 1-phenylazo-2-naphthol according to OECD Guideline 202. A limit test at sample concentration of 10.0 mg/L was performed. Effects on immobilisation were observed for 48 hours. The test was performed under static conditions in a fresh water system at a temperature of 20 °C ± 1 °C. EC50 was calculated. The median effective concentration (EC50) for the test substance, 1-phenylazo-2-naphthol, in Daphnia magna was determined to be >10.0 mg/L for immobilisation effects.

Although the second experimental study result indicates that the median effective concentration (EC50) to be >10.0 mg/L for immobilisation effects. The classification is not possible since the data is not conclusive based on the classification criteria mentioned in CLP regulation ( 48 hr EC 50 (for crustacea) = >10 to ≤100 mg/L). Thus, based on the first experimental study (Key study), the substance 1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9) was considered to be non-toxic to aquatic invertebrates and considered to be not classified as per the CLP regulation.

Although based on the first experimental study (Key study), the substance 1-phenylazo-2-naphthol (Sudan Orange 220) (CAS No.842-07-9) was considered to be non-toxic to aquatic invertebrates and considered to be not classified as per the CLP regulation, since it is classified in Aquatic chronic category 4 as per the Harmonised classification - Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation), the same has been considered for the dossier.