1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)pyridin-2(1H)-one, compound with 2-aminoethanol (1:1)

Short-term toxicity to fish

Description of key information

In one Key study Octopirox was found to be toxic to Zebrafish after 96 hrs at a nominal test item concentration of 1.58 mg/L and higher. Therefore, the NOEC was laid down as 0.89 mg/L (nominal test item concentration). The LC50 (96 hrs) is 1.89 (1.78-2.01) mg/L

In 4 Non Key studies Octopirox was found to be toxic to fish after 96 hrs at a nominal test item concentration between 0.25 and 0.722 mg/L. All this studies was done with normal water and not with river water and therefore the forming of chelate complexes was not considered.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1.89 mg/L

Additional information

Octopirox forms chelate complex with two and three valent ions like Fe(II), Fe(III), Al(III). If the test organism is dependent from such ions during the test e.g. algae, daphnia, this will influence growth and survival. As these ions mentioned before are ubiquitous in the sewer, the sewage treatment plant and in the environment e.g. river Octopirox forms immediately these chelate complexes. In order to avoid interference with the necessary test conditions in the Guideline tests and to avoid unrealistic test test settings e.g. pronounced toxicity by interference with essential ions, the aquatic ecotoxicity tests were carried out in river water where the ions mentioned above are present.