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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Link to relevant study record(s)

Description of key information

In the key study, the toxicity of alpha-methylstyrene to Desmodesmus subspicatus CHODAT was investigated 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 11.44 mg/L based on mean measured concentrations (geometric mean). 

Key value for chemical safety assessment

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

Additional information

In total, there are 4 study results available to cover this endpoint. However only the most recent one (P&D REACH Consortium, 2010) is considered appropriate for risk assessment purposes. The other studies have been evaluated to be non-reliable based on the described test conditions/results or based on the fact that the validity criteria set forward in the OECD Guideline 201 (K3) were not met. Details on the non-suitability of these studies is provided in the respective RSS.

The toxicity of alpha-methylstyrene 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). The 72 h NOEC, LOEC and EC50 based on growth rate were determined to be 2.26, 8.3, and 11.44 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.