3,3'-dioctadecyl-1,1'-methylenebis(4,1-phenylene)diurea

Toxicity to aquatic algae and cyanobacteria

Description of key information

Under the conditions of the present study with Pseudokirchneriella subcapitata , no reduction of growth rate was recorded at or below the test item concentration present in a 0.45 µm filtered solution prepared at nominal 100 mg/L (<0.2 mg/L). Due to the very low solubility of the test item in water, concentration levels that might be toxic for algae could not be reached. Therefore, the EC50 for growth rate reduction (ErC50: 0-48h) exceeded the maximum solubility in test medium.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

0.9 mg/L

Additional information

The study NOTOX. B.V. (2007) was performed to assess the reduction of growth and inhibition of yield of Pseudokirchneriella subcapitata after 48 hours of exposure to the water soluble fraction of the test substance. A combined limit/range-finding test was performed with exponentially growing algal cultures exposed to a blank-control, a 0.45 µm filtered solution prepared at nominal 100 mg/L and dilutions containing 1.0 and 10% of the filtrate. Based on the very low solubility of the test substance and the limited sensitivity of the analytical method, actual concentrations in the filtrate at the start of the test were below the detection limit of 0.2 mg/L. No reduction of growth rate was recorded at or below an test item concentration present in a 0.45 µm filtered solution prepared at nominal 100 mg/L (<0.2 mg/L). Due to the very low solubility of the test item in water, concentration levels that might be toxic for algae could not be reached. Hence, the EC₅₀for growth rate reduction (E_RC₅₀: 0-48h) exceeded the maximum solubility in test medium.

The study is a GLP compliant guideline study, acceptable without restriction for assessment of this endpoint.