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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Scenedesmus subspicatus (OECD 201): EL50(96h) > 100 mg/L loading rate WAF, NOELR: 100 mg/L loading rate WAF 

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
100 mg/L

Additional information

The growth inhibition effect of the test substance on the green algae species Desmodesmus subspicatus (strain: CCAP 276/20, reported as Scenedesmus subspicatus) was investigated according to OECD guideline 201(Mead, 2004). Following a preliminary range-finding test, the test organisms were exposed to a Water Accomodated Fraction (WAF) of the test material at a single nominal loading rate of 100 mg/L (six replicate flasks) for 96 hours under constant illumination (approximately 4000 Lux) and shaking. The temperature was held constant at 24 ± 1 °C. Samples of the algal population were collected daily and cell concentrations determined for each control and treatment group using a Coulter® Multisizer Particle Counter. As results an Effective Loading rate, EL50 greater than 100 mg/L loading rate WAF and the corresponding No Observed Effect Loading Rate of 100 mg/L is reported. It was considered unnecessary and unrealistic to test a loading rate in excess of 100 mg/L.