Disodium 3,3'-[sulphonylbis[p-phenyleneazo(5-imino-3-methyl-1H-pyrazole-4,1-diyl)]]bis(benzenesulphonate)

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 the 20th of July to the 05th of August, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Test conducted according to an internationally accepted test guideline.

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)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Disodium 3,3'-[sulphonylbis[p-phenyleneazo(5-imino-3-methyl-1H-pyrazole-4,1-diyl)]]bis(benzenesulphonate)

EC Number:

275-148-4

EC Name:

Disodium 3,3'-[sulphonylbis[p-phenyleneazo(5-imino-3-methyl-1H-pyrazole-4,1-diyl)]]bis(benzenesulphonate)

Cas Number:

71033-19-7

Molecular formula:

C32H26N10Na2O8S3

IUPAC Name:

disodium 3,3'-[sulphonylbis[p-phenyleneazo(5-imino-3-methyl-1H-pyrazole-4,1-diyl)]]bis(benzenesulphonate)

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

At the beginning of the test, as well as after 24 and 48 h of exposure.

Test solutions

Vehicle:

yes

Details on test solutions:

Elendt M4 medium

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
Daphnia magna (Straus, 1820) derived from a healthy stock and not first brood progeny
Age: less than 24 h
TEST SYSTEM
Breeding: parental and young Daphnia held in 4 L glass aquaria (3 L medium) at 20 ± 2 °C
Illumination: 16 h photoperiod a day, supplied by overhead white fluorescent tubes
Medium: continuously aerated Elendt M4 medium; prepared with ultra-pure water (conductivity <1.5 µS/cm)
Feed: Suspension of Desmodesmus subspicatus (green algae) in Elendt M4 medium with an optical density OD680 of about 15 units
Control of sensitivity: acute reference test with potassium dichromate conducted twice a year

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Test temperature:

22 °C
Determined in an additional flask without Daphnia at the beginning of the test and after 24 and 48 h of exposure.

pH:

6.5 - 7.2
Determined in the combined test solutions for each concentration at the beginning and after 48 h of exposure.

Dissolved oxygen:

5.3 - 7.2 mg/L
O2 concentration and pH were measured in the test medium for each concentration including the blank control. If the O2 concentration was too low (>5.0 mg/l required) the media was aerated by stirring.
Determined in the combined test solutions for each concentration at the beginning and after 48 h of exposure.

Conductivity:

672 - 709 µS.cm-1

Nominal and measured concentrations:

Nominal concentrations were 130, 59.1, 26.9, 12.2 and 5.55 mg/L test item
corresponding to 100, 45.5, 20.7, 9.39 and 4.27 mg/L of the active ingredient.

Details on test conditions:

Test vessel: 100 ml flasks, all-glass, with 50 ml of test medium, covered with a glass plate to avoid evaporation and contamination of the test solutions with dust
N. Daphia: 40 individuals per test concentration, 20 per vessel
Light: 16 h photoperiod a day, supplied by overhead white fluorescent tubes
Feed: the Daphnia are not fed during the test

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

54.9 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Details on results:

PRELIMINARY, NON-GLP TEST
% immobile Daphnia after 48 h of exposure: 70 at 130 mg/L loading rate
DEFINITIVE TEST
The test concentrations of during the 48 h test period were measured by HPLC analysis. The HPLC measurements were conducted at the beginning of the test (0 h) and after 24 and 48 h of exposure. These analyses confirmed the right dosage of the test item, and showed that the concentrations of the test item were satisfactorily maintained over the whole 48 h test period.
As all measured concentrations corresponded to 80-120% of the nominal concentrations, the effective concentrations ErCx/EyCx were assessed based on the nominal concentrations of the active ingredient.

Results with reference substance (positive control):

Acute reference test with potassium dichromate conducted twice a year.
The EC50 value for the control of sensitivity for 24 h of exposure with potassium dichromate was estimated to be 0.89 mg/L (data from 29 June 2016), which lies within the recommended range of 0.6–2.1 mg/L according to OECD Guideline 202.

Reported statistics and error estimates:

Statistical analysis was performed with respect to the effect concentrations (including 95% confidence limits)

Any other information on results incl. tables

The effect concentration ECx is the concentration leading to immobilization of x % of the Daphnia after 24 or 48 h of exposure. Those individuals not able to swim within 15 s after gentle agitation of the test vessel were considered to be immobile (even if they were still able move their antennae). The effect concentration ErC50 and EyC50 were determined with ToxRat® Standard Version 2.10 (ToxRat® Solutions GmbH, Alsdorf, Germany).

The no observed effect concentration (NOEC) is the highest concentration tested for which the observed effect is not significantly different from the blank controls. Immobilization rates of <=10% are regarded as not biologically significant.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

A test is considered valid if not more than 10% of the Daphnia in the control were immobilized, trapped at the surface of the water, or showed any signs of disease or stress. The dissolved oxygen concentration at the end of the test has to be ≥3 mg O2/L.

Conclusions:

EC50 Daphnia magna (24h): > 100 mg/L
EC50 Daphnia magna (48h): 54.9 mg/L
based on the nominal concentrations of the active ingredient.

Executive summary:

Method

The median effect concentration (EC50) and the no-effect concentration (NOEC) of the substance to Daphnia magna were investigated under static exposure conditions over a period of 48 h, following the guideline OECD 202.

The test item is solid, well soluble (328.5 ± 1.81 g/L at 20.0 ± 0.5 °C) and has a purity of 77.1% (active ingredient). The test solutions were prepared by respective dilutions of a stock solution.

The investigated nominal concentrations were 130, 59.1, 26.9, 12.2 and 5.55 mg/L test item, corresponding to 100, 45.5, 20.7, 9.39 and 4.27 mg/L of the active ingredient.

40 individual Daphnia divided into 2 test vessels were exposed to each concentration of the test item, and 60 Daphnia divided into 3 test vessels were used as blank controls. The test concentrations of during the 48 h test period were measured by HPLC analysis. The HPLC measurements were conducted at the beginning of the test (0 h) and after 24 and 48 h of exposure.

These analyses confirmed the right dosage of the test item, showed that the concentrations of the test item were satisfactorily maintained over the whole 48 h test period (102, 101, 99, 98 and 102%, respectively, of the initial value) and that they all corresponded to 80-120% of the nominal concentrations.

Therefore, the effective concentrations ErCx/EyCx were assessed based on the nominal concentrations of the active ingredient.

Observations

After 24 h of exposure, no significant effects (≤10% immobilization) were observed at any of the test concentrations or in the blank controls.

After 48 h of exposure to the test item, following immobilization rates were observed:

77.5% at 100 mg/L

52.5% at 45.5 mg/L.

No significant effects (≤10% immobilization) were observed at the nominal concentrations of 20.7, 9.39 and 4.27 mg/L or in the blank controls.

Conclusion

The 48 h EC50 value to Daphnia magna is 54.9 mg/L. This value is based on nominal concentrations of the active ingredient. All validity criteria were fulfilled.