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Environmental fate & pathways

Hydrolysis

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Description of key information

In accordance with REACH Annex VIII column 2, the study does not need to be conducted if the substance is readily biodegradable or highly insoluble in water.
The following statement was included in a physico-chemical properties study by Walker & White (2010) concerning the feasibility of a partition coefficient study on the test substance:
"No determination was possible according to Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004 and Method C7 Abiotic Degradation, Hydrolysis as a Function of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008, due to the following reasons:
• During method development, it was found that the test item was insoluble in water and all of the typical laboratory solvents tested; the solvents used were methanol, acetonitrile, tetrahydrofuran, dichloromethane, hexane, chloroform, toluene, ethyl acetate, methyl-tert-butyl ether and isooctane. Therefore, it was considered that a substance-specific, stability-indicating analytical method was not possible in this instance.
• Methods 111 and C7 are not applicable for test items which are insoluble in water."
The following study was also provided in support of omitting the test.
Yoder, R. (2003) Electrospray Ionization Mass Spectrometric Study of Dioctyltin Compounds in Solution.
The study was performed to a good standard, and assigned a reliability score of 2. Electrospray ionization mass spectrometry (ESI/MS) was used to determine whether dioctyltin compounds in water behave like dibutyltin compounds and form oxides relatively quickly The results of the test confirmed this theory. During the study, the test solutions were analysed immediately after the addition of, the analyses provided an indication of the speed of hydrolysis. In all samples hydrolysis products were observed under very short times. In particular, at 125 ng/ml (as Sn), almost the entire parent compound has converted to the oxide in less than 10 minutes (estimated).

Key value for chemical safety assessment

Additional information

Yoder (2003) was provided in support of omitting testing for this endpoint. The study was performed to a good scientific standard with a good level of reporting and was accordingly assigneed a reliability score of 2. The study demonstrated that hydrolysis is extremely rapid. The study was provided for information purposes only, the purpose of the study was to determine experimentally whether dioctyltins behave hydrolytically similarly to dibutyltin compounds.