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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Similar salts show effects to algae from 50 mg/l.  It is not known if this is a genuine hazardous effect or simply slowing growth by preventing light.

Key value for chemical safety assessment

EC50 for freshwater algae:
50 mg/L

Additional information

From assessment of similar sulphonated azo substances, there is no indication that CJ321 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.


The potassium / sodium salt resulted in effects in the range 10 – 100 mg/l and is classified Aquatic Chronic 3. This may be due to the aminosulphonyl group which is not present in the other assessed dyes, so in the absence of further data, it is recommended to classify CJ321 on this basis.


The read-across is valid and is backed up by review documents, including an assessment of azo dyes by the Danish EPA that conclude low environmental toxicity to aquatic organisms.