2-[[(4-methoxyphenyl)methylhydrazono]methyl]-1,3,3-trimethyl-3H-indolium methyl sulphate

Short-term toxicity to aquatic invertebrates

Description of key information

The 24-hr EC50 of the test item to Daphnia magna is 0.57 mg/L. In asecond study, the 48-h EC50 was determined to be 0.3162 mg/L. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.316 mg/L

Additional information

Two studies are available for the assessment of the acute toxicity of the test item to aquatic invertebrates (Daphnia):

In the first study (Capsers, 1989), the 24–hr-acute toxicity of the test item to Daphnia magna was studied at nominal concentrations of 0.32, 1.0, 3.2, 10, 31.6 and 100 mg/L. Test conditions were similar to the standard test guideline EU Method C.2 (Acute toxicity for Daphnia). The 24–hour EC₅₀ was determined to be 0.57 mg/L. The study is considered to be valid and reliable but is however not suitable for classification purposes as the test duration is too short.

The second study (Ciba-Geigy, 1993), investigated the acute toxicity to Daphnia for up to 48 hrs at nominal concentrations of 0 (blank control), 0.01, 0.10, 1.0, 10 and 100 mg/L. The 48-hr EC₅₀ was determined to be 0.3162 mg/L.

This study is, however, only poorly documented.

Both studies demonstrate effect values within the same order of magnitude. The EC₅₀ (48-h) of Ciba-Geigy (1993) is below the EC₅₀ (24-h) of Caspers (1989) and is considered to be plausible. Therefore, the 48-h EC₅₀ of 0.3162 mg/L is used as key value in the chemical safety assessment.