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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The EC50 was determined to be >1000 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L

Additional information

A single data source was available to address this endpoint. The study was assigned a reliability score of 2 according to the criteria of Klimisch et al. (1997) and has therefore been used as the key value for this endpoint.

The potential of the test material to inhibit activated sludge was investigated in a study which was conducted in broadly in accordance with the standardised guideline OECD 209.

A mixed population of activated sewage sludge microorganisms from a predominantly domestic sewage source was exposed to the test material for a contact time of 3 hours. Following a preliminary toxicity test, the concentration tested was limit value of 1000 mg/L.

The sample was maintained at 21°C with continuous aeration and used on the day of collection. The pH was buffered to pH 7.3 with sodium hydroxide solution and the suspended solids level equal to 3.7 g/L prior to use.

The percentage inhibition of growth caused by the test material was assessed by measuring the O₂ consumption rates. The test material caused 9 % inhibition of growth.

Under the conditions of this study the EC50 was determined to be >1000 mg/L.