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Physical & Chemical properties

Water solubility

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Description of key information

not applicable.

However, a transformation/dissolution tests according to OECD 29 was conducted to investigate the possible release of the most ecotoxicological relevant individual inorganic building blocks of this substance (i.e., the elements Zn and Sn) in aqueous media.

The solubilities at 20°C were found as follows:

- determination via tin (Sn):

< 0.3 mg/L with a loading rate of 0.2 g/L

0.5 mg/L with a loading rate of 1.0 g/L

- determination via titanium (Ti):

< 0.5 mg/L with a loading rate of 0.2 g/L

0.9 mg/L with a loading rate of 1.0 g/L

- determination via tungsten (W):

6 mg/L with a loading rate of 0.2 g/L

35 mg/L with a loading rate of 1.0 g/L

- determination via zinc (Zn):

0.8 mg/L with a loading rate of 0.2 g/L

1.2 mg/L with a loading rate of 1.0 g/L

Key value for chemical safety assessment

Additional information

The determination was conducted by flask method according to OECD Guideline 105. The solubilities of test substance were quantified on tin, titanium, tungsten and zinc using inductively coupled plasma mass spectrometry (ICP-MS) after automated acid digestion.

The test item consists of a mixture of different metal oxides. The water solubility can therefore only be investigated via determination of dissolved amounts of the metals contained in the test item.

A transformation/dissolution test according to OECD 29 was conductd. The screening test showed that the most relevant pH with respect to ecotoxicology is at pH 6, i.e. where the highest release of the most relevant metal (Zn) was measured. Therefore, it was decided to conduct the acute full test at pH 6. The worst-case, i.e. the highest concentrations within the 7 days study period (three replicates) were 0.011 and < 0.001 mg/L for Zn and Sn at a loading rate of 1 mg/L. At at loading rate of 10 mg/L the maximum levels were 0.028 mg/L for Zn and 0.001 mg/L for Sn. For the highest loading rate (100 mg/l), the higest concentrations for Zn and Sn were 0.30 and 0.002 mg/L for Zn and Sn, respectively.

The results of the full acute transformation/dilution test indicates that no additional Zn is released with increasing study period. Thus a chronic 28 day test at 1 mg/l loading was not conducted.