2,2-dioctyl-1,3,2-oxathiastannolan-5-one

Short-term toxicity to fish

Description of key information

DOT(EHMA) induced no visible effects in zebra-fish (Brachydanio rerio) at or below a Water Accommodated Fraction (WAF) prepared at a loading rate of 100 mg/L over 96 hours. Based on average measured concentrations the NOEC corresponded to 24.8 mg DOT(EHMA) per litre (3.91 mg tin per litre).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

24.8 mg/L

Additional information

The Migchielsen, 2004, study (as amended by Migchielsen and de Haan, 2005) was chosen as the key study for this endpoint. The study was a 96-hour Acute toxicity study in zebra-fish with DOT(EHMA), conducted according to the EEC directive 92/69, Part C. L "Acute toxicity for fish"; and the OECD guideline No. 203: "Fish Acute Toxicity Test", Adopted 17 July, 1992.

The batch of DOT(EHMA) tested was a white to light yellow liquid enriched with 87.5% DOT(EHMA). DOT(EHMA) was not soluble in test medium at the concentrations tested. Preparation started with a supersaturated dispersion at 100 mg/l, which was stirred for approximately 24 hours applying an ultra thurrax. The dispersion was then left to stabilise for one hour. Subsequently, the Water Accommodated Fraction (WAF) was separated from the undissolved fraction of test substance by means of siphoning. The lower test concentrations were prepared by subsequent dilution of the WAF in test medium. All test solutions were renewed daily and all test vessels were pre-conditioned for 30 minutes with the respective solution. A limit test was combined with a range-finding test in a semi-static system with daily renewal. Seven zebra-fish per test group were exposed to a blank-control and a WAF prepared at a DOT(EHMA) loading rate of 100 mg/l in the limit test, while three zebra-fish per test group were exposed to dilutions containing 0.1, 1.0 and 10% of the WAF in the additional range-finding test. Samples for analytical confirmation of actual exposure concentrations were taken from freshly prepared solutions of the blank-control and the undiluted WAF at t=0 h and t=72 h and from the 24-hour old solutions at t=24 h and t=96 h. Analysis showed that the measured tin concentrations decreased slightly during the 24-hour renewal periods. Analyses further showed poor repeatability of test solution preparation. This was not unexpected considering the extremely low solubility of the test substance in the test medium in combination with the difficulties encountered with the separation of the undissolved from the dissolved fraction, which is a common feature when testing WAFs. The study met the acceptability criteria prescribed by the protocol and the guidelines and was considered valid. DOT(EHMA) induced no visible effects in zebra-fish (Brachydanio rerio) at or below a Water Accommodated Fraction (WAF) prepared at a loading rate of 100 mg/l. Based on average measured concentrations the NOEC corresponded to 24.8 mg DOT(EHMA) per litre (3.91 mg tin per litre).

The Grade, 1993, study is presented as supporting information only, the study was conducted according to EC Method C.1 and the result presented was a 96-hour LC50 of >5.8 mg/L.

Those two reports indicate that DOTE is not toxic or harmful to fish up to its expected water solubility (< 1.0 mg/L).