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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

o-cresol: EC3 (8 d) = 6.8 mg/L on Microcystis aeruginosa (DEV L9)
m-cresol: EC3 (8 d) = 13 mg/L on Microcystis aeruginosa (DEV L9)
p-cresol: EC10 (48 h) = 4.6 mg/L on Desmodesmus subspicatus (DIN 38412, part 9)

Key value for chemical safety assessment

Additional information

In a weight of evidence approach it can be shown that NOEC (EC3) and EC10 values for all cresol isomers are similar and range between 4.6 to 13 mg/L.

The toxicity of o-cresol and m-cresol to the blue-green alga Microcystis aeruginosa (Cyanophyceae) was determined in a cell multiplication inhibition test according to the guideline DEV L9 (Bringmann 1975, Bringmann and Kuehn 1976, 1978). The following test conditions were met: continuous light, 27°C, with or without neutralization, pH of the neutralized test solution was 7. The relevant nominal 8d-NOEC (EC3) for growth rate was 6.8 mg/L for o-cresol and 13 mg/L for m-cresol.

The effects of p-cresol on the green alga Desmodesmus subspicatus was tested according to DIN 38412, part 9 (draft standard for cell multiplication inhibition). Based on nominal concentrations a 48 h-EC50 of 21 mg/L and an EC10 of 4.6 mg/L, both related to growth rate, were determined (Kuehn and Pattard 1990).