N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)isophthalamide

Toxicity to aquatic algae and cyanobacteria

Description of key information

The study (CERI, 2010) was conducted in order to estimate the effect on the test organisms under the solubility of the test item in medium. As a result, in pH unadjusted test, the EC50 and NOEC of the test item were 27 mg/L and 1.0 mg/L, respectively. The pH of the test solution at the start of exposure in the higher test item concentration tended to be higher (pH was 9.4 in 98 mg/L exposure level which was the highest exposure level at the start of exposure). Therefore the pH of test solution was adjusted to around that of medium, and this study was conducted. As a result, the EC50 and NOEC of the test item were 52 mg/L and 3.2 mg/L, respectively. The effect on the test organism was eased somewhat. Therefore, it was considered that the effect of the test item on the test organism was the total effect of pH and toxicity of the test item and the results from experiments with adjusted pH were used for the assessment  (EC50 and NOEC: 52 mg/L and 3.2 mg/L).
In a second study (Pharmakon, 1997), the following results were obtained: 
- EC50, for freshwater green algae (actual concentration of test article): Growth curves (IA) EC50 > 250 mg/l, Growth rates (Iµ) > 250 mg/l 
- NOEC, for freshwater green algae (actual concentration of test article): Growth curves (IA) NOEC > 250 mg/l, Growth rates (Iµ) > 250 mg/l 

Key value for chemical safety assessment

EC50 for freshwater algae:

52 mg/L

EC10 or NOEC for freshwater algae:

3.2 mg/L