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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The toxicity of the test substance to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 (2011) and Council Regulation (EC) No. 761/2009 Method C.3 under GLP conditions. The 72h-ECr50 -value was determined to be 24.7 mg/L and the 72h-ErC10 was determined to be 6.5 mg/L . The NOEC-value for inhibition of growth rate after 72 hours was determined to be 0.8 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
24.7 mg/L
EC10 or NOEC for freshwater algae:
6.5 mg/L

Additional information

The toxicity of the test substance to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 (2011) under GLP conditions. The study was conducted under static conditions with an initial cell density of 6305 cells/mL. Five solutions with the nominal test item concentrations 0.800 -2.53 - 8.00 - 25.3 -80.0 mg/L (factor 3.16) were freshly prepared with dilution water and stirred for 30 minutes (1100 rpm, room temperature) until the solutions were visually clear. The concentrations of the test item in all test concentrations and the control were analytically verified by GC-MS at the start and the end of exposure. The measured concentrations of the test substance were determined to be 0.836, 2.5, 7.89, 23.95 and 77.65 mg/L. The measured concentrations of the test substance in the fresh media (0 h) with algae were between 93 and 111% of the nominal values. The measured concentrations in the old media (72 h) containing algae were in the range of 92 to 99% of the nominal values. Therefore all effect values given are based on the nominal test item concentrations of the test substance. The validity criteria were met. The EC50-values with 95 % confidence intervals for inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were 24.7 (23.8 - 25.6) mg/L and 9.23 (8.05 - 10.6) mg/L, respectively. The 72h-ErC10 was determined to be 6.5 mg/L and the 72h-EyC10 was determined to be < 0.800 mg/L.The NOEC-values for inhibition of growth rate and yield after 72 hours were 0.800 and < 0.800 mg/L, respectively.