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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The aquatic toxicity of the read across substance  2,2-Dimethyl-3-(3-methylphenyl)-propanol to the unicellular freshwater green alga Scenedesmus subspicatus was determined. The NOEC was 7.2 mg/L (inhibition of biomass growth and inhibition of growth rate). The EC50-values for inhibition of biomass growth (EbC50) and specific growth rate (ErC50) were 19 and 27 mg/L, respectively. 

Key value for chemical safety assessment

EC50 for freshwater algae:
27 mg/L
EC10 or NOEC for freshwater algae:
7.2 mg/L

Additional information

A read across approach was applied for short-term toxicity to aquatic invertebrates using data of 2,2-Dimethyl-3-(3-methylphenyl)-propanol (CAS 103694 -68 -4) as this substance was considered to show similar ecotoxicological properties as compared to the test item. For further justification please refer to IUCLID section 13.

The aquatic toxicity of the read across substance 2,2-Dimethyl-3-(3-methylphenyl)-propanol to the unicellular freshwater green algae Scenedesmus subspicatus was determined according to the principles of OECD-Guideline 201. The study was conducted under static conditions over a duration of 72 hours with an initial cell density of nominally 10^4 cells/mL. 5 concentration levels were tested in a geometrical series with a dilution factor of 2: nominal: 6.25 - 12.5 - 25 - 50 - 100 mg/L corresponding to overall mean measured concentrations: 7.2 - 15 - 31 - 64 - 131 mg/L. 3 replicates were tested for each concentration level and 6 replicates for control. The concentrations of the read across substance were determined from all freshly prepared media after 0 h and from old media after 72 h via GC/MS. All effect levels were given based on the mean measured concentrations. The EC50 (based on inhibition biomass growth) was determined to be 19 mg/L. The EC50 (based on growth rate related inhibition) was determined to be 27 mg/L, the NOEC (based on biomass and growth rate) was determined to be 7.2 mg/L.