Titanium carbide

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 2011 to February 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD Guideline for testing of chemicals - draft proposal - February 2001. Transformation dissolution of metals and metal compounds in aqueous media

Qualifier:

equivalent or similar to guideline

Guideline:

other: The Standard Operating Procedure for the Transformation/Dissolution of Metals and Sparingly Soluble Metal Compounds, Version February 2004; proposed by CANMET and LISEC

Principles of method if other than guideline:

Standardized amounts of powdered solids are added to specified simulated aquatic media and amounts of the relevant soluble metal ion are measured after defined timepoints.

GLP compliance:

no

Type of method:

other: Transformation/Dissolution Test

Water solubility:

0 µg/L

Temp.:

21.8 °C

pH:

5.97

Remarks on result:

other: pH screening test, time point 24 h, below method detection limit (MDL); blank

Water solubility:

0 µg/L

Temp.:

21.8 °C

pH:

6

Remarks on result:

other: pH screening test, time point 24 h, below method detection limit (MDL); sample loading 100 mg/L

Water solubility:

0 µg/L

Temp.:

21.9 °C

pH:

7.1

Remarks on result:

other: pH screening test, time point 24 h, below method detection limit (MDL); sample loading 100 mg/L

Water solubility:

0 µg/L

Temp.:

21.2 °C

pH:

7.1

Remarks on result:

other: pH screening test, time point 24 h, below method detection limit (MDL); blank

Water solubility:

0 µg/L

Temp.:

24.1 °C

pH:

7.99

Remarks on result:

other: pH screening test, time point 24 h, below method detection limit (MDL); blank

Water solubility:

0 µg/L

Temp.:

24.1 °C

pH:

7.98

Remarks on result:

other: pH screening test, time point 24 h, below method detection limit (MDL); sample loading 100 mg/L

Water solubility:

0 µg/L

Temp.:

21.9 °C

pH:

6.03

Remarks on result:

other: total dissolved Ti, 7 day full T/D-test, 1 mg/L loading

Water solubility:

0.5 µg/L

Temp.:

21.7 °C

pH:

5.83

Remarks on result:

other: total dissolved Ti, 28 day full T/D-test, 1 mg/L loading; comparison to value in blank sample: 0.5 µg Ti/L

Water solubility:

0.2 µg/L

Temp.:

23.6 °C

pH:

6

Remarks on result:

other: total dissolved Ti, 7 day full T/D-test, 10 mg/L loading; comparison to value in blank sample: 0.2 µg Ti/L

Water solubility:

0.2 µg/L

Temp.:

23.8 °C

pH:

5.97

Remarks on result:

other: total dissolved Ti, 7 day full T/D-test, 100 mg/L loading; comparison to value in blank sample: 0.2 µg Ti/L

Details on results:

Transformation/dissolution of titanium carbide samples showed no metal release in any of the tests performed compared to the corresponding blanks. The pH screening test showed titanium releases below the method detection limit (MDL) after the 24 hours tests at pH 6, 7 and 8. Most metals present higher solubility at lower pH, therefore pH 6 was selected to perform the full T/D test. In the 7 and 28 days the T/D results indicate that titanium release measurements were close to the MDL or below the MDL for 1, 10 and 100 mg/L sample loading, and for those test where concentrations above the MDL were measured no differences respect to the background levels (blanks) were observed.
The results as a whole showed extremely low solubility of titanium carbide (less than 0.4 μg/L), in OECD in vitro environment, simulating fresh water conditions.

Conclusions:

Interpretation of results: insoluble (< 0.1 mg/L)
Transformation/dissolution of titanium carbide samples showed no metal release in any of the tests performed. Therefore, titanium carbide is considered to be insoluble in water.

Executive summary:

A transformation/dissolution (T/D) test equivalent to OECD guideline for testing of chemicals: Transformation dissolution of metals and metal compounds in aqueous media (2001) was carried out to study the potential of titanium carbide to release metal to the environment. A 24 hour screening test to determine the pH of maximum titanium release was performed at pH 6, 7 and 8 with a loading rate of 100 mg/l. The pH screening test showed titanium releases below the method detection limit (MDL, 0.4 µg/L). The full T/D test was conducted at pH 6. The acute endpoint (7 days), was performed at a sample loading of 1, 10 and 100 mg/L; the chronic endpoint was determined from the extension of the 1 mg/L loading test to 28 days. The results of the study indicate that titanium release measurements were close to the MDL or below the MDL for 1, 10 and 100 mg/L sample loading, and for those tests where concentrations above the MDL were measured no differences to the background levels (blanks) were observed. Therefore, titanium carbide is considered to be insoluble in water.

Description of key information

A transformation/dissolution test equivalent to the OECD Guideline for testing of chemicals on Transformation dissolution of metals and metal compounds in aqueous media is available showing that titanium carbide is insoluble in water. As key value the limit of detection (0.4 µg/L) was set as worst-case value for water solubility.

Key value for chemical safety assessment

Water solubility:

0.4 µg/L

Additional information

The results of the transformation/dissolution study indicate that titanium release measurements were close to the method detection limit (MDL) or below the MDL for 1, 10 and 100 mg/L sample loading. For those tests where concentrations above the MDL were measured no differences in comparison to the blank levels were observed. Therefore, titanium carbide is considered to be insoluble in water.