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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

ErC50 (72 hrs, Pseudokirchneriella subcapitata) OECD guideline 201 (Alga, Growth Inhibition Test): >0.129 mg/L ( geom. mean of measured concentration), limit test.
Since this concentration was considered around solubility of test substance, ErC50 72h (nominal) was considered >100 mg/L.

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 GLP study was conducted as a limit test in order to confirm the effect of the test item on the test organisms at around the solubility of the test item in medium. The concentration of test item in the test solution at the preparation was a low value (0.129 mg/L) compared with the solubility in medium (0.208 mg/L). However, considering the variation of each test vessel at the solubility measurement (0.144 to 0.266 mg/L), it was judged that the concentration of test item at the preparation was almost around solubility in medium. The concentrations of test item in the test solutions were significantly decreased during the exposure, to finally result in a mean value of 0.0215 mg/L. The reason was estimated to the limit in algae growth inhibition study of the volatile substance (volatilization to headspace in the test vessel) and hydrolysis of test item. It was concluded that the test item did not have an effect on the test organisms at around the solubility of the test item in medium because no adverse effect was observed under the conditions of the definitive study. Furthermore, though the hydrolysate of test item was confirmed during exposure, it also had no adverse effect to test organisms. Therefore, it is considered that there was no effect to exposure by hydrolysis of test item.