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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 acute toxicity study conducted following methods described in OCD test Guideline No. 20, cultures of Selenastrum capricornutum were exposed to a structural analogue of the substance, tetrahydromethylphthalic anhydride (MTHPA), at nominal concentrations of 10, 18, 32, 56 and 100 mg/L under static conditions. An EC50 (72 hr) of 68 mg/l (growth rate 24 -72hr) and 64 mg/l (biomass, 72hr) were reported and the NOEC value determined was 27.5 mg/l (growth rate, 24-72 hr and biomass, 72hr).

 

In accordance with ECHA guidance on information 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.