2-Pyridinesulfonamide, N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-3-(2,2,2-trifluoroethoxy)-, sodium salt (1:1)

Toxicity to microorganisms

Description of key information

3 h EC50 > 100 mg/L, NOEC 100 mg/L, OECD 209, EEC L133 s. 118-122, Grade 1999

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

100 mg/L

Additional information

The effect of the test material on the respiration rate of activated sludge was investigated in accordance with the standardised guidelines OECD 209 and EEC L133 s. 118-122 (Official Journal of the European Communities, May, 30, 1988). Activated sludge was exposed to nominal concentrations of the test material at 1.0, 3.2, 10, 32 and 100 mg/L with controls and a reference substance (3,5-dichlorophenol) run concurrently for comparison. Percentage inhibition was not seen above 3 % at any of the test concentrations. The 3 hour EC₅₀ was therefore determined to be >100 mg/L. The test material was determined to be none toxic to bacteria. The EC₂₀ and EC₈₀ were also determined to be > 100 mg/L. The EC₅₀ obtained from the reference substance and the respiration rate range displayed by the two control groups were within the acceptable range and fulfilled the validity criteria. The study is considered to be reliable, relevant and adequate for risk assessment purposes. Under the conditions of the test, the NOEC is therefore equivalent to the highest concentration tested 100 mg/L. The study was performed in line with GLP and accepted standardised guidelines with a high standard of reporting. The study was assigned a reliability score of 1 and considered suitable for assessment as an accurate reflection of the test substance. The available data is considered to be complete and the 3 h EC50 value > 100 mg/L determined under the conditions of the test, was taken forward for risk assessment.