Indeno[4,3a-b]furan, decahydro-2,2,7,7,8,9,9-heptamethyl-

Toxicity to microorganisms

Description of key information

The effect of the test material on the respiration of activated sewage sludge was studied according to OECD TG 209 and EPA Draft OPPTS 850.6800 guideline. The study was in compliance with GLP criteria. The water solubility of the test material was shown to be less than 0.202 mg/L. The activated sewage sludge was exposed to test material at a concentration of 1000 mg/L (three replicates) and 0.20 mg/L (one replicate) for a period of 3 hours at 21°C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 30 minutes and 3 hours contact time and compared to data for the control and a reference material, 3,5-dichlorophenol. Two methods were employed to disperse the test material in the test system. In method 1, a test concentration of 0.20 mg/L was prepared by using a stock solution in dimethylformamide. In method 2, a test concentration of 1000 mg/L was prepared by dispersing the test material directly in water with the aid of ultrasonication. Using this approach, the effect of an excess amount of undissolved test material can be assessed. It is for determining whether the test material has any effect on the activated sewage sludge micro-organisms exoenzymes or whether the uptake of undissolved test material by processes such as phagocytosis has any adverse effect on the activated sewage sludge. The results showed that at concentration limit or above the water solubility, the test substance has no significant effect on the respiration rate of activated sewage sludge microorganisms. For the 0.20 mg/L treatment, the 3h-EC50 and NOEC were determined to be > 0.20 mg/L and ≥ 0.20 mg/L. For the 1000 mg/L treatment, the 3h-EC50 and NOEC were determined to be > 1000 mg/L and ≥ 1000 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L