Reaction mass of 5,5'-[sulphonylbis(3,1-phenyleneazo)]bis[6-amino-4-hydroxynaphthalene-2-sulphonic acid] and disodium 5,5'-[sulphonylbis(3,1-phenyleneazo)]bis[6-amino-4-hydroxynaphthalene-2-sulphonate]

Short-term toxicity to aquatic invertebrates

Description of key information

EC50 Daphnia magna (48h): 54.9 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

54.9 mg/L

Additional information

The following data was obtained for the Similar Substance 01. It is expected that the Target substance will present similar effect levels to daphnia. Justification for Read Across is given in Section 13 of IUCLID.

 

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.

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.

In 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.