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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The substance is not deemed to be toxic to algae.

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L

Additional information

The influence of the test substance Reactive Blue 75311 on the growth of the green algaScenedesmus subspicatusChodat was investigated in a 72-hour static test according to the OECD Guideline No. 201 The nominal test concentrations were 12.5, 25, 50 and 100 mg test substance/L and a control. Analytical concentrations (TOC) at start and end of the test period were comparable. However, the highest nominal test concentration of 100 mg/L calculates to only about 71 mg/L (arithmetic mean) from TOC. The study conducted yielded the following results:

72 h EC50 growth rate > 71 mg/L (>28 mg/L TOC) – nominal: > 100 mg/L

72 h EC50 biomass 48 mg/L (19 mg/L TOC)

72 h NOEC 18 mg/L (7 mg/L TOC)

72 h LOEC 33 mg/L (13 mg/L TOC)

Based on the effects noted, it was assumed that the results may be due to algistatic effects of the dyestuff, rather than actual toxicity observed. A further assessment of this endpoint was therefore conducted to assess the effects of light absorption. This investigation indicated that effects noted in the original algal study were due to light absorption rather than associated toxicity. On this basis the substance is not deemed to be toxic to algae. No classification and labelling is applicable. This was agreed by the German Member State Authority in the original notification of the substance under the 7thAmendment.