1-naphthalenesulfonic acid, 5-[(4-hydroxyphenyl)amino]-8-(phenylamino)-, reaction products with sodium sulfide (Na2(Sx)), leuco derivatives

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:

August - February 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

For determination of the test item concentration, five replicate samples were taken from the test item treatment group at the start (prior to distributing of the test item solution to the test vessels) and four replicates at the end of the test. Four control samples were analysed on both analytical occasions. The samples taken were sent to individual analysis.

Vehicle:

yes

Remarks:

ISO medium

Details on test solutions:

As the test item is poorly soluble in deionized water as well in the test medium, for preparation of test solution the water-accommodated fraction (WAF) approach was taken, as described in OECD Guidance Document No. 23. A supersaturated solution (100 mg/L nominal loading) was prepared by adding an amount of 0.0404 g test item in the first renewal period and 0.0416 g test item in the second renewal period in 400 mL test medium (ISO Medium) one day before the start of each renewal period. The test solution was handled by ultrasonic bath for 10 minutes, thereafter stirred for a period of 24 hours to achieve an equilibrated concentration. The test solution was then filtrated through a membrane filter (0.45 µm; Thermo Nalgene® membrane1 used on 29th August 2017 and membrane2 used on 30th August 2017) to separate the possible non-dissolved test material. The test solution was freshly prepared in the testing laboratory just before introduction of the test animals (start of the experiment).

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain: Straus
- Source: Laboratory of Hydrobiology (Central Agricultural Office, Directorate of Plant-, and Soil Protection) 2100 Gödöllő, Kotlán S. u. 3. Hungary
- Age of animals: Less than 24 h old at the beginning of the test
- Feeding during test: no

ACCLIMATION
- Acclimation period: no, breeding same as test conditions

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

20.3 – 21.0 °C

pH:

7.90 - 8.16

Dissolved oxygen:

7.37 – 7.94 mg/L

Nominal and measured concentrations:

Nominal concentration: 100 mg/L in WAF
Geometric mean measured concentration: 1.91 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beaker
- Size, fill volume: 50 mL, 40 mL
- Aeration: no
- Semi-static conditions: renewal on day 1
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: at least 4 mL test solution/animal

TEST MEDIUM / WATER PARAMETERS
- Preparation of dilution water: ISO medium, according to OECD 202)

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: The test item is unstable in light therefore the experiment was carried out in complete darkness, as described by OECD 202

EFFECT PARAMETERS MEASURED:
Immobility: after 24 and 48h

RANGE-FINDING STUDY
- Test concentrations: 100 mg/L nominal (WAF)
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 1.91 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.91 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: no
- Observations on body length and weight: no
- Other biological observations: no
- Mortality of control: no
- Other adverse effects control: no
- Abnormal responses: no
- Any observations that might cause a difference between measured and nominal values: no

Results with reference substance (positive control):

The 24h EC50 value was determined to be 1.41 mg/L (95% conf. limits: 1.19 – 1.68 mg/L), which falls within the range of 0.6 mg/L and 2.1 mg/L as given in the guideline [5].

Validity criteria fulfilled:

yes

Conclusions:

The test item had no toxic effect at aquatic saturation (i.e. limit test concentration) on Daphnia magna; the EC10, EC20, EC50 results and the LOEC are higher than the solubility level of the test item in the test medium, which corresponds to 1.91 mg/L.

Executive summary:

Acute toxicity of the test item was assessed on Daphnia magna in a 48-hour Acute Immobilisation Test. Young Daphnia were exposed to aqueous test media containing the test item for 48 hours in a static test. A limit test was performed in which, the test animals were exposed to aqueous test media containing the test item for 48 hours at the limit of its solubility in the test medium (i.e. saturation) plus a control in order to demonstrate that the test item has no influence on the mobility of Daphnia up to at least the saturation concentration (equivalent to 100 mg/L nominal concentration, prepared as water-accommodated fraction (WAF)). The quantification of the test item was performed by a previously validated analytical method by the analytical laboratory of TOXI-COOP ZRT. Samples were taken from the test concentration and the control at the start, before and after the renewal and at the end of the experiment and analysed by UV/VIS spectrophotometric method. The mean determined exposure concentration of the test item remained between 63 and 79% throughout the test in comparison to that of the measured test item concentration at the start of the test, and was 1.91 mg/L which was calculated as the geometric mean of the measured start and end concentrations. Healthy, young daphnids < 24 hours of age and with known origin, history and acclimatisation conditions were used. Twenty Daphnia (divided into 4 concurrent batches) were tested each, exposed to the saturated test concentration and in the control. Each test vessel contained approximately 40 mL test medium. Fully characterized (content, physico-chemical characteristics) ISO Medium was used as test medium. The immobilisation of the test animals was recorded 24 and 48 hours after test start. Environmental conditions were recorded. All measured values remained within the acceptable ranges. There was no immobilisation in twenty daphnids exposed to either test item treated or control group. In addition to immobility, no abnormal behaviour or appearance of test animals was detected. All validity criteria were met and therefore the study can be considered as valid.

Description of key information

The test item had no toxic effect at aquatic saturation (i.e. limit test concentration) on Daphnia magna; the EC10, EC20, EC50 results and the LOEC are higher than the solubility level of the test item in the test medium, which corresponds to 1.91 mg/L.