Tetrasodium 4,4'-bis[[4-[bis(2-hydroxyethyl)amino]-6-(4-sulphonatoanilino)-1,3,5-triazin-2-yl]amino]stilbene-2,2'-disulphonate]

Toxicity to aquatic algae and cyanobacteria

Description of key information

ErC50 (72h) > 100 mg/l (nominal)

NOEC (72h, growth rate) > 100 mg/l (nominal)

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 toxicity of the substance to aquatic algae was evaluated by considering data on the substance and data from studies on the similar substances. Justification for Read Across is given in Section 13 of IUCLID

The influence of 3a-MSA on the growth of the green alga Scenedesmus subspicatus chodat was investigated. The study was performed according to the OECD Guideline 201. Based on the growth inhibition curve, the NOEC and the LOEC values were found to be 500 mg/l and 1000 mg/l, respectively. The EC50 values after 72 and 96 hours was >1000 mg/l (RCC Umweltchemie AG., 1990). The result is in agreement with a second study on the substance, for which just a summary is available (Solvias AG, 1999).

The toxicity of 3a-DSA to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 and Council Regulation (EC) No. 266/2016/Method C.3 for the determination of the effects on growth rate and yield over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 5416 cells/ml in a limt test at 110 mg test item/l. Six replicates were tested for each test item concentration and six replicates for the control. The environmental conditions were within the acceptable limits. ErC50 (72hrs) > 110 mg/l (nominal); NOEC (72hrs, growth rate) = 110 mg/l (nominal)

The toxicity of 1 -MSA to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 and Council Regulation (EC) No. 266/2016/Method C.3. The aim of the study was the determination of the effects on growth rate and yield over a period of 72 hours.

The study was conducted under static conditions with an initial cell density of 5416 cells/ml. A stock solution with a nominal concentration of 120 mg test item/l was freshly prepared with dilution water. Five concentrations were tested in a geometrical series with a factor of √10: 1.20 - 3.79 - 12.0 - 37.9 - 120 mg/l. Three replicates were tested for each test item concentration and six replicates for the control. The environmental conditions were within the acceptable limits. The concentrations of the test item were determined at the start of the exposure (0 hours) and at the end of the exposure (72 hours) of all tested concentration levels and the control via HPLC-DAD. The measured concentrations of the test item were in the range of 96 to 101 % of the nominal values at the start of the exposure (0 hours) and 102 to 111 % of the nominal values at the end of the exposure (72 hours).

ErC50 (72h) > 120 mg/l (nominal)

The choice of the use of data from the two similar substances 1 -MSA and 3a-DSA is due to the fact that 1-MSA has the same level of sulfonation, while 3a-DSA contains two sulfonate groups, but it is part of the same group. The difference in the sulfonation degree is identified in the different effect levels obtained in the relevant studies for the two similar substances. The results on the substance itself, identified an ErC50 of > 1000 mg/l and a NOEC of 500 mg/l, are much higher than the results obtained for the similar substances. It is however important to note that the studies on the similar substances did not evaluate the toxicity of the test substance in such high concentrations and therefore the toxicity of the similar substances in higher concentrations is not known.