Registration Dossier

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Administrative data

Endpoint:
surface tension
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because based on structure, surface activity is not expected or cannot be predicted
the study does not need to be conducted because surface activity is not a desired property of the material
the study does not need to be conducted because water solubility is below 1 mg/L at 20°C
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
In accordance with column 2 of REACh Annex VII, the test does not need to be conducted if the water solubility is below 1 mg/L.
As presented under As presented under IUCLID Section 4.8, the criteria is fulfilled.
Moreover, the present substance is not intended to be used as a surfactant (i.e. not a desired property), and the constituents (isomers of a thioester/ketone) do not contain groups (such as distinct polar and non-polar parts) indicating that surface-active properties would be expected in solution. Therefore, the study is deemed unnecessary.
Cross-reference
Reason / purpose for cross-reference:
data waiving: supporting information
Reference

The true water solubility of the parent substance is considered to be <0.5 µg/L (experimental).

Suspensions are easily formed in water, which cannot be completely separated with usual techniques, so oversaturation is anticipated in actual conditions.

Metabolites DD-ma and DD-mp are estimated to have a solubility of respectively 85 and 47 mg/L, but anticipated to ionise and to increase up to ca 27 and 8.6 g/L at environmental pH (>=5).

Metabolite DD is estimated to have a solubility of ca 40 mg/L.

Water solubility:
0.5 µg/L
at the temperature of:
25 °C

An experimental study on water solubility measurement of the substance, was conducted under GLP, and considered as fully reliable. In order to refine the previous limit value obtained, another study was conducted, with several non-guideline methods, but nevertheless considered to be scientifically acceptable, with regard to obtaining a solution free of suspended particles. The lower result obtained was retained as the maximum measurable true concentration.

As risk assessment requires a figure in the above "key value" box (no < or > sign accepted), this limit value will be used as default data for CSA purpose.

Moreover, as the parent substance is likely to degrade into DD-ma, DD-mp and DD, supporting information is provided also on the solubility of the metabolites, which are the relevant species for the environmental risk assessment.

The water solubility was estimated using QSAR calculations. Four models, using different methodologies, were tried (WSKowWin, WaterNT, SPARC and VCClab), however three were discarded as not able to handle salts/ionised species, or considered to be of poor reliability for the substances of concern. Therefore only WSKowWin was retained in the present dossier. All compounds were within the applicability domain, and the predictibiity was confirmed by comparison with experimental values (Wsol and logK) from the parent compound.

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion

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