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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

For algae (Desmodesmus subspicatus) the acute toxicity of Multi-Walled Carbon Nanotubes (MWCNT) according to Directive 92/69/EEC, C.3 was 134 mg/l (nominal, inhibition of the algal population as reduction in growth rate, 72 h-ErC50) and 8.9 mg/l (nominal, No Observed Effect Concentration, NOEC) (Weyers, 2007b; Richter, 2011). In a second study with algae (Desmodesmus subspicatus) the acute toxicity of MWCNT according to Directive 92/69/EEC, C.3 was 278 mg/l (nominal, inhibition of the algal population as reduction in growth rate, 72 h-ErC50) and 4.3 mg/l (nominal, No Observed Effect Concentration, NOEC) (Weyers, 2007c).

Test material is meeting the form as described in section 4.5 of the IUCLID dossier.

Key value for chemical safety assessment

EC50 for freshwater algae:
120 mg/L
EC10 or NOEC for freshwater algae:
4.3 mg/L

Additional information

Concerning the study results of Weltens (2010c) the test system is assessed to be unsuitable (invalid) because the light reduction by the test item in the test concentration range clearly interferes with normal algal growth parameters. The inhibitory effect is mainly due to reduced light intensity. At the two highest concentrations however the inhibition of growth rate is significantly less in the simulation test than it was in the contact test, indicating that at these concentrations toxic effects are also contributing to the total effect.