Disodium 3-hydroxy-4-[(4-methyl-2-sulphonatophenyl)azo]-2-naphthoate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 July 2017 - 20 October 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23

Version / remarks:

2000

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Stability in water: stable

Analytical monitoring:

yes

Details on sampling:

Samples for analysis were taken from the test concentration and the control according to the schedule below:
Frequency at t=0 h and t=96 h
Volume 2.0 mL
Storage Samples were stored in a freezer (≤-15°C)

In addition, the filter containing the undissolved residue was kept for possible analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Direct application to the test medium.
All test solutions were individually prepared at loading rates of 1.0, 10 and 100 mg/L. A one day period of magnetic stirring was applied to ensure maximum dissolution of the test item in medium. Thereafter, the aqueous Water Accommodated Fractions (WAFs) were filtered through a 0.45 µm membrane filter and used as test concentrations.
- Controls: Test medium without test item or other additives.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): Solutions were checked for Tyndall effect with a laser pen. No distraction of the beam was observed. All test solutions were clear and colorless at the end of the preparation procedure.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name: carp
- Strain: Linnaeus, 1758
- Source: Zodiac, proefacc, "De Haar Vissen", Wageningen University and Research Centre, The Netherlands
- Age at study initiation: not indicated
- Length at study initiation: 2.7 ± 0.2 cm
- Weight at study initiation: 0.21 ± 0.07 g
- Method of breeding: in UV-treated water

ACCLIMATION
- Acclimation period: at least 12 days
- Acclimation conditions: same as test
- Type and amount of food during acclimation:
- Feeding frequency during acclimation: daily with pelleted fish food (Essence (300-500 um), Coppens International bv, Helmond, The Netherlands)
- Health during acclimation: mortality during the seven days prior to the start of the test was less than 5%

FEEDING DURING TEST: no

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

180 mg CaCO3/L

Test temperature:

21°C

pH:

7.9 at test initiation
7.5-7.8 throughout the remainder of the test

Dissolved oxygen:

9.0 and 8.9 at test initiation
6.5-9.0 throughout the remainder of the test.

Nominal and measured concentrations:

Nominal concentration: WAF prepared at 100 mg/L
Measured concentration: 0.151 mg/L at t=0 and 0.149 mg/L at t=96 (99% of initial measured concentration at t=0)

Details on test conditions:

TEST SYSTEM
- Test vessel: 6.5 litres, all-glass, fill volume: 5.0 litres
- Aeration: no
- No. of organisms per vessel: 7
- No. of vessels per concentration: 1
- No. of vessels per control: 1
- Biomass loading rate: 0.29 g fish/L

TEST MEDIUM / WATER PARAMETERS
- Test medium used: adjusted ISO medium according to OECD guideline 203
- Source/preparation of dilution water: tap-water purified by reverse osmosis
- Culture medium different from test medium: no
- Intervals of water quality measurement:
* Conductivity, pH, nitrate, nitrite and ammonia concentration: once a week
* Temperature: continuous
* pH and temperature were measured before transferring the fish to the test system

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours, daily

EFFECT PARAMETERS MEASURED: mortality at t= 2 1/2, 24, 48, 72 and 96 hours

TEST CONCENTRATIONS
- Justification for using less concentrations than requested by guideline: based on the results of a dose-range finding test, a limit test was performed.
- Range finding study
- Test concentrations: WAFs prepared at 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: yes, since no mortality or clinical effects were observed at any of the test concentrations during the test period, the LC50 was expected to exceed the highest WAF prepared at a nominal loading rate of 100 mg/L.

Reference substance (positive control):

yes

Remarks:

Pentachlorophenol (February 2017)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.15 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality (fish)

Details on results:

- No mortality occured during the test period. Mortality was not recorded at t=48. However, since no mortality occured during the test period, this deviation of the study plan does not influence the results of the study.
- No abnormalities were observed during the final test.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Mortality: all carp exposed to a concentration of 0.46 mg/L died within 24 hours, while no mortality occurred at 0.10 and 0.22 mg/L.
- LC50: 0.32 mg/L (95 % confidence interval between 0.22 and 0.46 mg/L)
- Other: since the results with the reference substance were within the historical data range, the carp used in this study are considered to be of anticipated sensitivy.

Validity criteria fulfilled:

yes

Remarks:

see 'overall remarks' section.

Conclusions:

Based on the results of an acute toxicty study in fish, according to OECD guideline 203 and GLP principles, the LC50 of D&C Red 6 was >0.15 mg/L, which was considered to be the maximum soluble concentration of the test item in test medium.

Executive summary:

An acute toxicity study in fish was performed, according to OECD guideline 203 and GLP principles, to assess the effect of D&C Red 6 on carp after 96 hours of exposure. The test solutions were prepared indivudually by adding the test item directly to the test medium, stirring for one day and subsequently filtering the WAFs. Loading rates of 1.0, 10 and 100 mg/L were used in a range-finding study. Since no effects were observed in the range-finding study, the highest concentration was used to determined the final effect concentrations. Seven fish (Cyprinus carpio) were exposed to the limit concentration for an exposure period of 96 hours in which mortality was recorded at t=2 1/2, 24, 72 and 96 hours. Samples of the test solution were analysed, which showed actual exposure concentrations of 0.151 mg/L at t=0 and 0.149 mg/L at t=96. Since the test item remained stable during the exposure period (99% of initial), the effect concentrations was based on the measured concentration.

No mortality or other abnormalities were observed. Therefore, the LC50 was determined to exceed the exposure concentration of 0.15 mg/L, which was considered to be the maximum soluble concentration of the test item in test medium.

All acceptability criteria were met and the study was considered to be valid.

Description of key information

An acute toxicity study in fish was performed, according to OECD guideline 203 and GLP principles, to assess the effect of D&C Red 6 on carp after 96 hours of exposure. The test solutions were prepared indivudually by adding the test item directly to the test medium, stirring for one day and subsequently filtering the WAFs. Loading rates of 1.0, 10 and 100 mg/L were used in a range-finding study. Since no effects were observed in the range-finding study, the highest concentration was used to determined the final effect concentrations. Seven fish (Cyprinus carpio) were exposed to the limit concentration for an exposure period of 96 hours in which mortality was recorded at t=2 1/2, 24, 72 and 96 hours. Samples of the test solution were analysed, which showed actual exposure concentrations of 0.151 mg/L at t=0 and 0.149 mg/L at t=96. Since the test item remained stable during the exposure period (99% of initial), the effect concentrations was based on the measured concentration.

No mortality or other abnormalities were observed. Therefore, the LC50 was determined to exceed the exposure concentration of 0.15 mg/L, which was considered to be the maximum soluble concentration of the test item in test medium.

All acceptability criteria were met and the study was considered to be valid.