2-ethylhexyl 4,4-dibutyl-10-ethyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecanoate

Short-term toxicity to fish

Description of key information

For the assessment of short term toxicity to fish, the following was submitted as the key study.
Steger-Hartmann. T & Wendt. B (1998) Acute toxicity of di-n-butyltin bis(2-ethylhexylthioglycolate) (ZK 26386) to the Zebra fish Danio rerio. Testing Laboratory: Schering AG, Experimentelle Toxikologie, D-13342 Berlin. Owner company: Witco GmbH, Bergkamen, Germany. Report No.: IC20. Report date: 1998-11-19.
The study was assigned a reliability score of 2, and considered suitable for assessment. The study was a limit test with a mean measured concentration of 11.4 mg/L. No deaths occurred at this concentration. No LC50 could be determined.
A further two studies were provided as supporting information.
Grade R (1993) Report on the acute toxicity test of Irgastab 17M to Zebra-Fish (Brachydanio rerio). Testing laboratory: CIBA-GEIGY Limited, Product Safety, Ecotoxicology, CH-4002, Basle, Switzerland. Owner company: CIBA-GEIGY Limited, AD - Division, CH-4002, Basle, Switzerland. Report No.: 928307. Company study No.: 928307. Report date: 1993-01-29.
Grade R (1993) Report on the acute toxicity test of Irgastab 22 M to Zebra-Fish (Brachydanio rerio). Testing Laboratory: CIBA-GEIGY Limited, Product Safety, Ecotoxicology, CH-4002, Basle, Switzerland. Owner company: CIBA-GEIGY Limited, AD - Division, CH-4002, Basle, Switzerland. Report No.: 928291. Report date: 1993-04-22
Both studies were assigned a reliability score of 2. The studies were both performed in compliance with GLP and according to the guideline EU Method C.1. However the test materials utilised in the study contained 61.8 and 65% of DBT(2-EHMA) respectively and were provided as supporting information.

Additional information

The key study, Steger-Hartmann. T & Wendt. B (1998), was a limit test with a mean measured concentration of 11.4 mg/L. This was a saturated solution, prepared as an emulsion and filtered. The test animals were exposed to this environment for a total exposure time of 96 hours, during which time the solution was aerated once (after the 48 hour observation). Aeration of the test solution is allowed according to OECD guideline 203, provided that it does not lead to significant loss of the test material from the solution. As the test material is an organotin complex it is highly unlikely that aeration of the test medium lead to loss of the test material. No deaths occurred at this concentration which was at or above the water solubility limit of the test material. The study was conducted to GLP and OECD guideline 203 and had a high purity of 99.7%, but the deviations in the preparation of the test solution reduce the reliability of the study to 2 on the Klimisch et al, 1999 scale. The supporting studies (Grade (1993) were both also assigned Klimisch ratings of 2 based on the quality of the method, reporting and accuracy of the results, but as they were based on mixtures rather than pure substances, they were not suitable to be key studies. The lowest LC50 value from a supporting study was determined as 11.7 mg/L with 95 % confidence limits of 7.2 - 19.0 mg/L. This is contradictory to the key study where no LC50 could be determined. The presence of Mono-n-butyltin tris (2-ethylhexylthioglycolate) at 35% could account for this difference.