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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The inhibitory effect of 3-Methylpyrazole of the respiration of activated sludge was determined as: 3h NOEC = 320 mg/l

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L
EC10 or NOEC for microorganisms:
320 mg/L

Additional information

Two GLP-studies with Klimisch score 1 are available:

The inhibitory effect of 3-Methylpyrazol on bacteria multiplication was tested by the Pseudomonas cell multiplication inhibition test according DIN 38 412, part 8.

The values of the effective concentrations are: EC10 124 mg/1, EC50 449 mg/1. The Inhibition of the Respiration of Activated Sludge when exposed to 3-Methylpyrazol was determined according to OECD 209 resp. EU C.11.

The following results for the test item 3-Methylpyrazol were determined:

inhibition based on total respiration:

3h NOEC < 1 mg/l

3h EC20 > 1000 mg/l

3h EC50 approx. 1000 mg/l

Inhibition based on heterotrophic respiration:

3h NOEC = 320 mg/L

3h EC20 > 1000 mg/L

3h EC50 > 1000 mg/L

The lowest NOEC value is chosen as key study.