Hexasodium 6,13-dichloro-3,10-bis[[2-[[4-chloro-6-[(2,4-disulphonatophenyl)amino]-1,3,5-triazin-2-yl]amino]ethyl]amino]triphenodioxazine-4,11-disulphonate

Toxicity to aquatic algae and cyanobacteria

Description of key information

No toxic effects against algae at 100mg/L were noted on the substance tested. By virtue of read across to this structural analogue, Reactive Blue 198 is also considered to have an 72h EC50 value of >100mg/L. The substance is not classified for effects on this basis.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

The influence of the test item on the growth of the green algal species Scenedesmus subspicatus CHODAT was investigated in a 72-hour static test according to the Commission Directive 92/69/EEC, Annex Part C.3, 1992, and the OECD Guideline No.

201, 1984. However, the test method was modified to quantify the algicidal effect of the test item, but also the growth inhibition effect caused by reduced light intensities in the colored test solutions.

The nominal test concentrations were 1.0, 3.2, 10, 32 and 100 mg/L and a control. All test media down to the lowest test concentration were slightly to strongly colored by the test item. In the test media the mean measured test item concentrations at the start of the test ranged from 91 to 104% of the nominal values. This shows the right dosage of the test item. During the test period of 72 hours a decrease of test item concentration in the lower test media was determined. At the end of the test 45 - 90% of the nominal values were found. The losses could be due to adsorption of the test item, particularly in the low-level samples. The total mean measured test concentrations (calculated as the average over all measurements per test concentration) in the test concentrations of nominal 100 to 3.2 mg/L varied in the range of 80 to 97% of the nominal values. Therefore, the reported biological results are related to the nominal test item concentrations. .

The total mean measured test concentration of the lowest test medium concentration of 1.0 mg/L was 68% of nominal. However, this result was not taken into account, since this concentration was below the highest concentration without significant inhibitory effects on

the growth of the alge in experimental part A. The same growth inhibition of Scenedesmus subspicatus was observed when the algae

grew in test water without test item, but under reduced light intensities by the filter effect of the colored test media as in the second parallel experimental part, where the algae grew in the test media with dissolved test item.

Thus, in conclusion, this modified algal test has clearly demonstrated that the observed growth inhibition effect of the test item on Scenedesmus subspicatus was caused only due to an indirect effect, the light filter effect in the colored test solutions. Thus, a toxic

effect of the test item on the algal cells can be excluded up to the highest test concentration of nominal 100 mg/L.