disodium 7-{[4-chloro-6-(dodecylamino)-1,3,5-triazin-2-yl]amino}-4-hydroxy-3-[{4-[(4-sulfonatophenyl)diazen-1-yl]phenyl}diazen-1-yl]naphthalene-2-sulfonate

Endpoint summary

Additional information

Acute aquatic toxicity of test substance was assessed in a 96-hour limit test on fish and in a 48 -hour limit test on daphnia.

Since no mortality of fish was seen, a LC50 > 86 mg/l as measured concentration (100 mg/l as nominal concentration) was found.

Exposure of daphnia to a filtrate solution did not induce acute immobilisation at measured concentrations ranging from 47 to 24 mg/l after 48 h. Hence an EC50 > 36 mg/l on average was found.

On the other hand, exposure to a supersaturated solution of 100 mg/l induced significantly immobilisation. This corresponded to concentrations of 81 and 45 mg/l in the 48 h exposure period. However, this effect on mobility was not indicative of a substance toxicity but more likely of mechanical obstruction of the ability to swim, caused by the presence of substance deposits.

Toxicity to aquatic algae was studied in a 72 -hour test. Analytically determined test substance concentrations in freshly prepared test media varied in the range from 47 % to 94.5 % of nominal values. At the end of the test, concentrations were in a range from 35.4 % to 49.7 % of nominal values due to a sedimentation of the suspended test substance.

As demonstrated by a modified test specifically developed for dyes, effects on algal biomass and growth rate were only due to the indirect action of test substance, namely light absorption. Any toxic effect of test substance on algal cells could be excluded up to the highest tested concentration of 41.2 mg/l (measured concentration corresponding to nominal concentration of 100 mg/l).

The toxicity to microorganisms was also studied. Since no inhibition of respiration rate was seen at all tested concentrations, an EC50 > 100 mg/l was determined.

According to the CLP Regulation (EC 1272/2008), the threshold of classification of a substance for short-term aquatic toxicity is 1 mg/l. Consequently, the substance is not classified for acute aquatic toxicity based on results obtained with fish, crustacea and aquatic algae.

In order to assess the potential toxicity upon chronic exposure, the substance was tested for long-term toxicity to crustacea (daphnia), which resulted as the most sensitive organism in the short-term studies.

Accordingly, a 22 -day test on daphnia was carried out. The analytically determined test substance concentrations in the samples from freshly prepared media varied in the range from 37 % to 101.7 % of nominal values. At the end of the renewal periods of 48 and 72 hours, measured concentrations were in the range from 31.9 % to 60.3 % of nominal values. The reason for these low measured levels was a sedimentation of the suspended test substance.

Based on the survival rate and the reproduction rate of the daphnia, a NOEC of 1.8 mg/l was determined.

No-observed effect concentrations for daphnia and algae, NOEC of 1.8 and 41.2 mg/l respectively, are above the threshold of classification for chronic toxicity (1 mg/l) of the CLP Regulation (EC 1272/2008). In addition, chronic toxicity to fish can be reasonably excluded based on the negative result with daphnia, namely the most sensitive species in acute toxicity studies,

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