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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The present study was performed according to OECD guidelines with the algae Pseudokirchneriella subcapitata and the substance showed reduced growth rate and inhibited the yield of this fresh water algae species with an EC50 for growth rate reduction of 5.5 mg/L and NOEC of 0.92 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
5.5 mg/L
EC10 or NOEC for freshwater algae:
0.92 mg/L

Additional information

The toxicity of the test substance to aquatic algae and cyanobacteria was assessed according to OECD guidelines and GLP principles. Nominal exposure concentrations in the final test were the following: control, 1.0, 3.2, 10, 32, 100 mg/L. The corresponding time weight average (TWA) concentrations were: control, 0.29, 0.92, 2.8, 9.1 and 29 mg/L. It was decided to express effect concentrations based on TWA concentrations since the substance, a Polyfunctional polyaziridine, based on TMPTA and Propylene imine, was not stable during the entire test period. The use of TWA concentrations ensures that a worst case scenario was assessed. The EC50 for growth rate reduction (ErC50: 0-72h) was 5.5 mg/l with a NOEC of 0.92 mg/L. For the yield inhibition, the EC50 (EyC50: 0-72h) was 3.8 mg/L with a NOEC 0.92 mg/L. All criteria for acceptability of the test were met and the present toxicity study is considered to be reliable without restrictions according to the OECD guideline No. 201.