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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Algal growth inhibition:  EC50 (72 hour) - 68 mg/L (growth rate); 64 mg/L (biomass).  NOEC - 27.5 mg/L (growth rate and biomass). 

Key value for chemical safety assessment

EC50 for freshwater algae:
68 mg/L
EC10 or NOEC for freshwater algae:
27.5 mg/L

Additional information

In a 72 hour study, the cultures of Selenastrum capricornutum were exposed to an analogue of the substance, tetrahydromethylphthalic anhydride (MTHPA), at nominal concentrations of 10, 18, 32, 56 and 100 mg/L under static conditions in accordance with OECD Guideline 201. An EC50 of 68 mg/L (growth rate) and 64 mg/L (biomass) were reported and the NOEC value determined was 27.5 mg/L (growth rate and biomass).


In accordance with ECHA guidance oninformation requirements and chemical safety assessment,Chapter R.7b: Endpoint specific guidance, theErC50 endpoint is used in DNEL derivation. This is because use of values based on biomass cannot be applied to an analysis of results from a system in exponential growth without logarithmic transformation.