Single Wall Carbon Nanotubes (SWCNT)

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 June 2016 - 24 June 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

Method 105 of
the OECD Guidelines for Testing of Chemicals, 27 July 1995.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Key result

Water solubility:

ca. 1 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

1 g/L

Incubation duration:

24 h

Temp.:

20 °C

pH:

> 7.9 - < 8.8

Details on results:

Any positive result would be mainly due to water extractible, adsorbed / entrained material, as opposed to the actual carbon nanostructures.
On completion of the equilibration period, the samples were colorless with the excess test item present as at least one large hydrophobic mass that had clumped together.

Conclusions:

The water solubility of the test item has been determined to be less than or equal to:

2.8 x 10-3 g/L of solution with respect to total organic carbon (TOC) and less than
1.0 x 10-3 g/L of solution with respect to inorganic carbon (IC) at 20.0 ± 0.5 °C.

Executive summary:

Water Solubility. Less than or equal to 2.8 x 10-3 g/L of solution with respect to total organic carbon (TOC) and less than 1.0 x 10-3 g/L of solution with respect to inorganic carbon (IC) at 20.0 ± 0.5 °C, using the flask method, designed to be compatible with Method A.6 Water Solubility of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals, 27 July 1995.

Description of key information

The water solubility of the test item has been determined to be less than or equal to 2.8 x 10-3 g/L of solution with respect to total organic carbon (TOC) and less than 1.0 x 10-3 g/L of solution with respect to inorganic carbon (IC) at 20.0 ± 0.5 °C.

Key value for chemical safety assessment

Water solubility:

1 mg/L

at the temperature of:

20 °C

Additional information

As the test item is essentially inorganic elemental carbon (IC) result is considered for further assessments. It is noteworthy that the material tested contained residual carbon black from its manufacturing process, and thus it cannot be excluded that the inorganic carbon measured may be attributable to the impurity rather than to the single-walled carbon nanotubes. More recent test results, performed in different laboratories (Hungary, UK and Israel) indicate that single-walled carbon nanotubes are entirely insoluble and thus in vitro mutagenicity studies could not be performed. Thus, the results for water solubility reported here should be considered with caution.