Crotonaldehyde

Toxicity to aquatic algae and cyanobacteria

Description of key information

Selenastrum capricornutum (Pseudokirchneriella subcapitata): EC50 (96 h): <0.881 mg/L; EC10 (96 h): <0.385 mg/L (measured values) 
Scenedesmus subspicatus (Desmodesmus subspicatus): Toxicity threshold (7 d): 0.78 mg/L (measured value)

Key value for chemical safety assessment

EC50 for freshwater algae:

0.881 mg/L

EC10 or NOEC for freshwater algae:

0.385 mg/L

Additional information

Two studies are available reporting the acute toxicity of crotonaldehyde to freshwater algae. No information is available regarding the acute toxicity to marine species. The first was conducted according to EPA OTS 797.1050 using Selenastrum capricornutum as the test species. In this study, an 96 hour ErC50 of < 0.881 mg/L and a 96 -hour ErC10 of < 0.385 mg/L were reported, both values based on mean measured concentrations. In a post exposure period, it could be shown, that the toxic effect of crotonaldehyde is algicidic rather than algistatic nature. In the second study, using Scenedesmus subspicatus as the test organism, a toxicity threshold of 0.78 mg/L was reported also based on measured values. This study was conducted according to an in-house method over a test period of 7 days, which is regarded as too long because a recovery of the algal cells during this period cannot be excluded. The most sensitive endpoint of these studies is the EC10 derived from the study conducted from the study with Selenastrum capricornutum. This value would be the key parameter for the risk assessment. Furthermore, this study was conducted according to a currently valid standard.