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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The following study was submitted as the key study to fulfil the data requirement for Toxicity to microorganisms:
Clarke N (2010) ASSESSMENT OF THE INHIBITORY EFFECT ON THE RESPIRATION OF ACTIVATED SEWAGE SLUDGE. Testing laboratory: Harlan Laboratories Ltd, Shardlow Business Park, London Road, Shardlow, Derbyshire, DE72 2GD, UK. Owner company: Organo Tin REACH Consortium, c/o ReachCentrum, Avenue E. Van Nieuwenhuyse 6, B-1160, Brussels, BELGIUM. Report No.: 3109/0005. Report date: 2010-08-16.
The study was assigned a reliability score of 1, the study was performed in compliance with GLP and in accordance with OECD 209. The effect of the test item 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 was 1000 mg/l.
Two further studies were providing as supporting information:
Dr. Beimborn (1999) Determination of the Inhibition of Oxygen Consumption by Activated Sludge by TZ 03498 in the Activated Sludge Respiration Inhibition Test. Testing Laboratory: BASF Aktiengesellschaft, Ecology and Environmental Analytics, Laboratory of Ecology, D-67056, Ludwigshafen, Germany. Owner company: Witco GmbH, Ernst-Schering-Str. 14, Postfach 1540, D-59179 Bergkammen, Germany. Report No.: 99/0606/08/1. Report date: 1999-10-25.
Baumann W (1999) Report on The test for Inhibitory Concentration on Aerobic Bacteria of Irgastab T 22 M. Testing laboratory: CIBA-GEIGY Limited, Product Safety, Ecotoxicology, CH-4002, Basel, Switzerland. Owner company: CIBA-GEIGY Limited, AD - Division, CH-4002, Basel, Switzerland. Report No.: 928290. Report date: 1992-11-16.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

The key study, Clarke N (2010), was performed in compliance with GLP and in accordance with the OECD guideline 209 ("Activated Sludge, Respiration Inhibition Test”). The study was selected as the key study as the most modern study available. Activated sewage sludge was exposed to an aqueous dispersion of the test item at concentrations of 10, 32, 100, 320 and 1000 mg/l for a period of 3 hours at a temperature of 21 ± 1 °C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 3 hours contact time and compared to data for the control and a reference item, 3,5-dichlorophenol. The effect of the test item 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 was 1000 mg/l. It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/l. The reference item gave a 3-Hour EC50 value of 5.1 mg/l, 95% confidence limits 3.7 – 7.0 mg/l.

 

Beimborn (1999) was assigned a reliability score of 1. The inhibitory effect of TZ 03498 on the respiration of activated sewage sludge was assessed in a study performed in accordance with OECD Guideline No. 209 and in compliance with GLP. The 3-Hour EC50 value was determined to be greater than 1000 mg/L.

 

Baumann (1999) was performed in compliance with GLP and to a good scientific standard, the study was assigned a reliability score of 2. The test material (trade name: Irgastab T 22 M) on which the study was performed contained 65% of the substance of interest (DBT(2-EHMA)). Activated sludge was exposed to TK 11638 for 3 hours. The EC50 (3 hours) > 100 mg/L and the substance is therefore not toxic to microorganisms.