Iron sulphide

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:

Guideline compliant study with good documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Type of method:

flask method

Key result

Water solubility:

< 0.87 µg/L

Incubation duration:

3 d

Temp.:

20 °C

pH:

>= 5.6 - <= 5.9

Conclusions:

Interpretation of results: insoluble (< 0.1 mg/L)
measured water solubility < 0.87 µg/L

Executive summary:

In the GLP Klimisch 1 key study from Anipol the water solubility of iron(II) sulfide was determined according to OECD 105. During the 3 days stirring period, the measeured concentrations were always below the LOD of 0.550 µg Fe/L corresponding to 0.866 µg FeS/L. Hence, the water solubility of iron sulfide is < 0.87 µg/L.

For the risk assessment, a water solubility of 0.87 µg FeS will be used.

The results of this study are considered relevant and reliable for the risk assessment.

Description of key information

0.87 µg/L

Key value for chemical safety assessment

Water solubility:

0.87 µg/L

at the temperature of:

20 °C

Additional information

For the water solubility, two studies are available: One GLP Klimisch 1 study and a Klimisch 3 study.

In the GLP Klimisch 1 key study from Aniol the water solubility of iron(II) sulfide was determined according to OECD 105. During the 3 days stirring period, the measeured concentrations were always below the LOD of 0.550 µg Fe/L corresponding to 0.866 µg FeS/L. Hence, the water solubility of iron sulfide is < 0.87 µg/L. For the risk assessment, a water solubility of 0.87 µg FeS will be used. The results of this study are considered relevant and reliable for the risk assessment.

For the determination of the water solubility of iron sulfide one Klimisch 3 key study is available (Paß 2011). This study was performed following OECD 105 and EU A.6 guidelines with the shake flask method. The deviations to the guidelines, e.g. set-up of two instead of three replicates and no determination of the pH, were minor and hence considered to have no impact on the outcome of the study. The major deviation to the test guideline was the concentration of the starting suspension. This starting suspension was prepared with a concentration of 25g/L and hence orders of magnitude higher than the expected (and later measured) water solubility. This is in deviation to the guideline which forsees a pretest and weighing in about 5 times more material than the final water solubility. When too high amounts are used to start the test, impurities might affect the water solubility. Hence, this deviation might have had a signigficant impact on the sulfur concentration in the test solutions since non-FeS sulfur might have been present and measured in the suspension as well. The water solubility of FeS at 20 °C was determined to be 2.1 *10^-2g/l (=21 mg/L) with a standard deviation of 0.0013 g/L (= 1.3 mg/L). Based on the applied method and the expected impact of the potentially excess sulfur in the test solutions caused by the extremly high initial amounts used to prepare the aqueous suspensions, this result is considered of minor relevance for the risk assessment.

For the risk assessment the result from the Klimisch 1 study from Aniol (2012) will be used. i.e., 0.87 µg FeS/L.