Phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide

Toxicity to aquatic algae and cyanobacteria

Description of key information

The test substance can be classified as non-toxic to fish up to the limit of its solubility, namely 0.0008 mg/L. 

Key value for chemical safety assessment

EC50 for freshwater algae:

0.26 mg/L

EC10 or NOEC for freshwater algae:

0.26 mg/L

Additional information

Owing to the light sensitivity of the product the study was conducted in two parts. In the first part the product was illuminated for 24 hours prior to its addition to the test medium. This part of the study showed that there was a 70% loss of the substance due to the prior illumination. In the second part the stock solution was prepared just prior to the start of the study, and there was a 95% loss of measured concentration over the test period. No effects on growth rate or biomass were recorded. All measured concentrations were determined to be above the solubility in the test medium.

 

Result: The mean algal cell densities in the test media of both filtrates at all counting dates were nearly identical with those in the parallel control cultures. Thus the substance and its degradation products had no inhibitory effect on the growth of Scenedesmus subspicatus during the exposure period of 72 hours. Therefore, the substance can be classified as non-toxic to algae up to the limit of its solubility.

 

The water solubility of the substance was determined to be lower than the detection limit (< 0.1 mg/L). However, the solubility of the substance was determined by HPLC analysis and UV/VIS-detection to be 0.0008 mg/L for the acute toxicity to Brachydanio rerio test.