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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The method followed that described in the OECD Guidelines for Testing of Chemicals (1984) No 209 "Activated Sludge, Respiration Inhibition Test", EEC Commission Directive 87/302/EEC and US EPA Draft Ecological Effects Test Guidelines OPPTS 850.6800.
The No Observed Effect Concentration (NOEC) after 3 hours exposure was 1000 mg/l. It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/l. The reference material gave a 3-Hour EC50 value of 11 mg/l, 95% confidence limits 8.9 - 14 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L

Additional information

Introduction:

A study was performed to assess the effect of the test material on the respiration of activated sewage sludge. The method followed that described in the OECD Guidelines for Testing of Chemicals (1984) No 209 "Activated Sludge, Respiration Inhibition Test", EEC Commission Directive 87/302/EEC and US EPA Draft Ecological Effects Test Guidelines OPPTS 850.6800.

Methods:

Following a preliminary range-finding test, activated sewage sludge was exposed to an aqueous dispersion of the test material at a concentration of 1000 mg/l (three replicate flasks) for a period of 3 hours at a temperature of approximately 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.

Results:

The effect of the test material on the respiration of activated sewage sludge gave a 3-Hour EC50 of greater than 1000 mg/l. The No Observed Effect Concentration (NOEC) after 3 hours exposure was1000mg/l.

It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/l. The reference material gave a 3-Hour EC50 value of 11 mg/l, 95% confidence limits 8.9 - 14 mg/l.