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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The toxicity of alphamethylstyrene to Desmodesmus subspicatus CHODAT was investigated in a study conducted according to OECD Guideline 201 (Alga, Growth Inhibition Test; 2006) and EU Method C.3 (Algal Inhibition Test; 2008) under static conditions. The test substance concentrations were determined by GC/FID. The 72 h NOEC, LOEC and EC50 based on growth rate were determined to be 2.26, 8.3, and 11.441 mg/L based on mean measured concentrations (geometric mean).

Key value for chemical safety assessment

EC50 for freshwater algae:
11.441 mg/L
EC10 or NOEC for freshwater algae:
2.26 mg/L

Additional information

Reliable results obtained in a guideline studies are available.

The toxicity of alphamethylstyrene to Desmodesmus subspicatus CHODAT was investigated in a study conducted according to OECD Guideline 201 (Alga, Growth Inhibition Test; 2006) and EU Method C.3 (Algal Inhibition Test; 2008) under static conditions. In the main test, the algal cultures were exposed to nominal concentrations of 0 (control), 10, 20, 40, 80, and 100 mg/L corresponding to mean measured concentrations of 0 (control), 2.26, 8.30, 10.72, 26.56, and 32.39 mg/L (geometric mean of t=0 h) for 72 h. The test substance concentrations were determined by GC/FID. The recoveries of the test substance concentrations after 72 h were < 80% of those determined at time 0, and the measured concentrations deviated more than 20% from the nominal values. Based on these findings, the reported effect concentrations refer to mean measured concentrations (geometric mean) of the measured concentrations at time 0. The 72 h NOEC, LOEC and EC50 based on growth rate were determined to be 2.26, 8.3, and 11.441 mg/L based on mean measured concentrations (geometric mean). The 72 h NOEC, LOEC and EC50 based on yield were determined to be <2.26, <=2.26, and 4.347 mg/L based on mean measured concentrations (geometric mean). The validity criteria of the guideline were fulfilled.

The toxicity of alpha-methylstyrene to Selenastrum capricornutum (current scientific: Pseudokirchnerella subcapitata) was investigated in a study conducted according to OECD Guideline 201 (Alga, Growth Inhibition Test). Cultures of Selenastrum capricornutum were exposed to alpha-methylstyrene at nominal concentrations of 0 (control), solvent control, 0.2, 0.5, 1.3, 3.2, 8.0, and 20.0 mg/L for 72 h under static conditions. For the preparation of the test solutions HCO-30 was used as solubilizing agent although the water solubility of AMS is ca. 100 mg/L; furthermore, the concentration of the solubilizing agent was not found in the Japanese report (only a few details reported in English) and the results thereof were not reported. The test substance concentrations were monitored via HPLC. The 72 h NOEC and EC50 values based on growth rate and initial measured concentrations were determined to be 0.3 and 4.8 mg/L, repectively. The corresponding NOEC and EC values based on biomass were determined to be 0.172 and 2.56 mg/L (initial measured), respectively.