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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Link to relevant study record(s)

Description of key information

The following was submitted as the key study for the endpoint Short-term toxicity to aquatic invertebrates.
Steger-Hartmann. T & Schmidt. M (1998) Acute immobilization test of di-n-butyltin bis(2-ethylhexylthioglycolate) (ZK 26386) with Daphnia magna. Testing laboratory: Schering AG, Experimentelle Toxikologie, D-13342 Berlin. Owner company: Witco GmbH, Bergkamen, Germany. Report No.: IC15. Report date: 1998-12-04.
The study was performed in compliance with GLP and OECD Guideline 202. The study was a limit test with a mean measured concentration of 1.4 mg/L. An LC50 value could not be determined from the results of the study.
A further study was provided as supporting information. The study was performed in compliance with GLP and to the guideline EU Method C.2. The test material on which the study was performed contained 65% of the substance of interest.
Grade R (1993) Report on the Acute Toxicity Test of Orgastab 22 M on Daphnia (Daphnia magna Straus 1820). Testing Laboratory: CIBA-GEIGY Ltd, Product Safety Ecotoxicology CH-4002 Basel / Switzerland. Owner company: CIBA-GEIGY Ltd AD - Division, CH-4002, Basel / Switzerland. Report No.: 928293. Report date: 1993-04-21

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
1.4 mg/L

Additional information

The key study, Steger-Hartmann. T & Schmidt. M (1998), was a limit test with a mean measured concentration of 1.4 mg/L. This was a saturated solution.

Some immobility was observed but as this level was less than the 10 % allowed immobilisation for a control group, it was determined this was not sufficient to class it as a substance related effect. The study was conducted to GLP and OECD guideline 202 and had a high purity of 99.7%, but no definitive EC50 value could be determined due to the limit of solubility having been reached. Because of this the Klimisch rating was assigned as 2. The EC50 value can only be quoted as > 1.4 mg/L.

The supporting study, Grade (1993), was also assigned a Klimisch rating of 2, but as it was based on a mixture rather than a pure substance, it was not suitable to be a key study. The 48 hour EC50 value from a supporting study was determined as 0.035 mg/L with 95 % confidence limits of 0.027 and 0.044 mg/L. It is likely this lower EC50 value is caused by the presence of Mono-n-butyltin tris (2-ethylhexylthioglycolate) at 35 % concentration.