Tin disulphide

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP and guideline complient study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Principles of method if other than guideline:

The chosen Flask method is based on the elution of the test item in water in closed test flasks that are shaken over a period of ≥ 3 d. The water solubility is determined when the mass concentration of the eluate is constant. This point is reached when the mass concentrations in at least the two last vessels do not differ by more than 15 %. Taking into account the anticipated low water solubility of the test item, and the fact, that it cannot be coated on an inert carrier, it was decided to accomplish the Flask method instead of the Column elution method, that is usually recommended for test items with a low water solubility of < 10-2 g/L.

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Remarks:

slow stirr

Key result

Water solubility:

0.67 µg/L

Temp.:

20 °C

pH:

>= 6.3 - <= 6.4

Table 1 Results of AAS-analysis (AAS = Atom-Absorption-Spectroscopy) of the Definitive Water Solubility TestofTin disulfide (Tin and Tin sulfide concentration in µg/L; mean values of
5 measurements) of the control and nominal testconcentration10.0 mg/L (time 1 – 5 d) in the test vessels.

 

Time (d)	Control cResults (µg Tin/L)	10 mg/LSnS2 cResults (µg Tin/L)	10 mg/LSnS2 cResults (µg Tin disulfide/L) *
1	< LOD *	0.440	0.678
2	< LOD *	0.370	0.570
3	< LOD *	0.324	0.499
4	< LOD *	0.424	0.653
5	< LOD *	0.448	0.690

 

Remark:   * Calculations based on the theoretical amount of 64.9 % Sn in SnS₂

 

 

Results of AAS-analysis (AAS = Atom-Absorption-Spectroscopy) of the Definitive Water Solubility Test with Tin disulfide at nominal test concentration of 10.0 mg/L were below 1µg/L. Deviation between results of day 4 and 5 was 5.4 %, hence the validity criterion of OECD-Guideline 105 was met (trigger for validity≤ 15 %).

According to OECD-Guideline 105 Water Solubility of the test item Tin disulfide was calculated from the mean value of results of AAS-analysis at time 4 d and 5 d.

Water Solubility of Tin disulfide: 0.67µg/L

Conclusions:

Interpretation of results: insoluble (< 0.1 mg/L)
Measured water solubility: 0.67 µg/L

Executive summary:

The water solubility of tin disulfide (purity 100%) was determined in a GLP study according to OECD 105 using the slow stirr method. The study was scored as Klimisch 1 study based on the good documentation of the methods and the results and following of the procedures outlined in the OECD 105 guideline. Tin disulfide was determined by measuring the concentration of dissolved tin moiety in the solution. The measeurd water solubility of tin sulfide was 0.67 µg/L. The results of this study are considered relevant for the risk assessment of tin sulfide.

Description of key information

0.00000067 g/L = 0.67 µg/L

Key value for chemical safety assessment

Water solubility:

0.67 µg/L

at the temperature of:

20 °C

Additional information

For the determination of the water solubility of tin disulfide one Klimisch 1 (Aniol 2012) and one Klimisch 2 study (Paß 2011) are available. Both studies were performed following OECD and EU guidelines with the shake flask method. The deviations to the guidelines were minor and hence considered to have no impact on the outcome of the study. However, both studies came to different results regarding the water solubility, i.e., 0.67 µg/L (Aniol, 2012) vs. 48 mg/L (Paß, 2011).

In the GLP- Klimisch 1 study from Aniol (2012) the water solubility was determined by analyzing the concentration of tin in the solution. The amount of test material which was used to prepare the saturated solution was 10 mg/L. In the study from Paß (2011), the sulfur moiety was measured and the concentration of the test material used to prepare the saturated solution was 25 g/L and hence orders of magnitude higher than the expected (and later measured) water solubility. it might be speculated that this higher amount of test material in the suspension might have caused higher concentrations of smaller particles in the final solution and the sensitivity of the sulfur detector was not as high as the sensitivity of the AAS detector for tin.  This might have resulted in the orders of magnitude higher water solubility values when compared to the result obtained from Aniol (2012).

Based on the better analytical procedures and the better documentation, the study from Aniol (2012) is considered to be relevant. The experimentally determined water solubility of 0.67 µg/L was considered as reliable and relevant for the further risk assessment.

The water solubility of tin disulfide is 0.67 µg/L