Sodium diisobutyldithiophosphinate

Toxicity to aquatic algae and cyanobacteria

Description of key information

An alga, Selenastrum capricornutum (now Pseudokirchneriella subcapitata), growth inhibition test was performed to evaluate the acute toxicity of the test material according to OECD TG 201 and under GLP conditions. The NOEC and EC50 based on growth rate were 20 and 115 mg/L, respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:

115 mg/L

EC10 or NOEC for freshwater algae:

20 mg/L

Additional information

An alga, Selenastrum capricornutum (now Pseudokirchneriella subcapitata), growth inhibition test was performed to evaluate the acute toxicity of the test material according to OECD TG 201 and under GLP conditions.

The nominal treatment concentrations for the test were 150, 60, 20, 5, 0.5, 0.05 mg/L and a control of algal nutrient media. A stock solution was prepared by adding the appropriate amount of test material to algal nutrient media. The stock solution was mixed (<10% vortex) on a magnetic stirplate with a Teflon coated stirbar for 1 hour. Treatments were prepared by adding the appropriate amount of stock solution to algal nutrient media. Samples were removed from each treatment and analyzed for carbon content. The alga were exposed to each treatment level for a 96-hour period under static conditions.

The calculated material values generally ranged from 94 to 100% of the nominal concentrations and are within the variability of the analytical method. As such, the nominal concentrations were used for statistical evaluation and reporting.

The calculated 96-hour NOEC (No Observable Effect Concentration) and LOEC (Lowest Observable Effect Concentration) values were 20 mg/L and 60 mg/L, respectively, based on both growth rate and biomass. The calculated 96 -hour E_bC50 and E_rC50 values were 35.1 mg/L and 115 mg/L, respectively.