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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The toxic effects of the test substance on the oxygen consumption rate of aerobic microorganisms (activated sludge) after short-term exposure of 180 min were determined according to the OECD 209 (2010). The EC50 was determined to be nominal 90 mg/L and the EC10 was determined to be nominal lower than 62.5 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:
90 mg/L

Additional information

The objective of this key study (BASF SE, 2015) according to OECD 209 (2010) was to determine the toxic effects of the test substance on the oxygen consumption rate of aerobic microorganisms (activated sludge) after short-term exposure of 180 min, compared with the blank control. The test was performed in nominal concentrations of 0 (control), 62.5, 125, 250, 500 and 1000 mg/L without correction of the purity. No concentrations were measured. The inoculum was activated sludge from a municipal waste treatment plant of Mannheim, Germany. The sludge concentration was 1.5 g/L and a synthetic medium according to the guideline was used. A reference substance (3,5-dichlorphenol) was used as positive control. The EC50 value of the reference substance 3,5-dichlorphenol was determined to be 19.1 mg/L, which was within the acceptable limits (2 to 25 mg/L), as specified in OECD 209 Guideline.

In addition the coefficient of variation of the six replicates of blank control was determined to be 9.5 % O2 consumption. The mean oxygen uptake of the blank controls was determined to be 25 mg/g*h. In conclusion, the results in this study are consistent with all validity criteria and the test is valid according to the guidelines used for this study. The EC50 was determined to be nominal 90 mg/L and the EC10 was determined to be nominal lower than 62.5 mg/L.