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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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toxicity to aquatic algae and cyanobacteria
Data waiving:
study technically not feasible
Justification for data waiving:

Description of key information

The test material CJ304 is a dark colored dye which when mixed in test medium will impart dark color. Due to light absorption, colored substances such as dyes can inhibit algal growth, which is not the result of a toxic action. This shading effect can confound measures of chemical toxicity and thus impair the risk assessment. In an effort to avoid this problem Lemna minor Growth Inhibition test (static) was conducted.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:
100 mg/L

Additional information

From assessment of similar substances, it is concludes that CJ304 need not be classified as hazardous to aquatic organisms on the basis of effects to aquatic plants. Although some references show an inhibition of growth rates biomass at concentrations below 100 mg/l, it is considered very likely that this is mainly due to absorption of light at wavelengths liked to photosynthesis.


No convincing evidence has been found that the substance causes harm to aquatic plants, other than shading from the coloured material.