Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate was assessed for its toxicity towards algae according to EU method C.3 and OECD guideline 201. The ErC50 (72 h) based on growth rate was determined to be 34 mg/L (95% confidence limit 30.7 - 37.9). The NOEC (growth rate, 72h) was 4.3 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
34 mg/L
EC10 or NOEC for freshwater algae:
4.3 mg/L

Additional information

The toxicity of sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate towards green algae Pseudokirchnerella subcapitata was assessed for a 72 hours exposure according to EU method C.3 and OECD guideline 201.

Due to the results of a pre-test the nominal concentrations of test item for the main test were selceted as 0.9, 1.9, 4.3, 9.4, 21, 45 and 100 mg test substance/L. Additionally, a blank control without test substance was tested.

During the test the actual test concentrations in the analysed test media were in the range of 98.57 - 126.32 % of the nominal values.

Consequently, the EC-values were calculated from the nominal concentrations.

The EC50 (72 h) based on growth rate was determined to be 34 mg/L (95% confidence limit 30.7 - 37.9). The NOEC (growth rate, 72 h) was 4.3 mg/L.

The EC50 (72 h) based on biomass was determined to be 12 mg/L (95% confidence limit 8.5 - 14.8). The NOEC (biomass, 72 h) was 1.9 mg/L.