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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Link to relevant study record(s)

Description of key information

The following study was submitted to address the endpoint Toxicity to Microorganisms on the structural analogue DBTO:
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. 3109/0024. Report date: 2010-05-21
The study was performed on the test material dibutyltin oxide. The study was assigned a reliability score of 1.

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L

Additional information

The study data available for the registrant have been conducted on the structurally analogous substance DBTO. The study Clarke N (2010) was performed in accordance with the OECD guideline 209 and in compliance with GLP. The study was therefore assigned a reliability score of 1 and considered adequate for assessment. 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 44 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 8.6 mg/l, 95% confidence limits 6.7 - 11 mg/l.