Aluminium nitride

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Series on Testing and Assessment No. 29 (23-Jul-2001): Guidance document on transformation/dissolution of metals and metal compounds in aqueous media

GLP compliance:

not specified

Type of method:

other: Transformation/Dissolution test

Water solubility:

ca. 1 087.1 µg/L

Temp.:

21.5 °C

pH:

ca. 8

Remarks on result:

other: T/D test (loading 100 mg/L) at pH 8: After 7 days the mean concentrations were: 1087.1 ± 69.6 μg Al/L and 2048.0 ± 244.3 μg NH3/L

Water solubility:

ca. 366 µg/L

Temp.:

21.5 °C

pH:

ca. 8

Remarks on result:

other: T/D test (loading 10 mg/L) at pH 8: After 7 days the mean concentrations were: 366.0 ± 11.4 μg Al/L and 664.0 ± 91.5 μg NH3/L

Water solubility:

ca. 202.9 µg/L

Temp.:

21.5 °C

pH:

ca. 8

Remarks on result:

other: T/D test (loading 1 mg/L) at pH 8: After 28 days the mean concentrations were: 202.9 ± 14.8 μg Al/L and 146.2 ± 13.2 μg NH3/L; an equilibrium had been reached after 336 h (14d); the first order rate constant was calculated to k=0.0100 Al / h

Details on results:

The screening test showed aluminium releases to be slightly higher at pH 8 than at pH 6 after 24 hours. Due to the higher solubility at higher pH, pH 8 was selected to perform the full T/D test. After 7 or 28 days, as appropriate, aluminium concentrations were measured to be 202.9 ± 14.8 µg Al/L, 366.0 ± 11.4 μg Al/L and 1087.1 ± 69.6 μg Al/L for the 1, 10 and 100 mg/L sample loadings, respectively.
Equilibrium had been reached in the 1 mg/L sample loading after 336 h (14d). Hence, the first order rate constant was calculated to k = 0.0100 Al/h.

Table 1:Screening test: Measured dissolved Al concentrations for the loading of 100 mg/L (target pH 8: 1, 2, 3; target pH 6: 4, 5, 6 – triplicate vessels per pH, duplicate samples per vessel)
sample	target pH	mean per vessel Al conc. μg/L	SD per vessel Al conc. μg/L	mean all Al conc. μg/L	SD all Al conc μg/L
1 24h	8	982.5	4.0	981.7	12.9
2 24h	8	993.6	10.3
3 24h	8	969.1	10.2
4 24h	6	75.5	0.7	76.4	1.1
5 24h	6	76.2	1.3
6 24h	6	77.5	0.7

 

Table 2: Screening test: Measured dissolved NH3concentrations for the loading of 100 mg/L (target pH 8: 1, 2, 3; target pH 6: 4, 5, 6 – triplicate vessels per pH, duplicate samples per vessel)
sample	target pH	mean per vessel NH3conc. μg/L	SD per vessel NH3conc. μg/L	mean all NH3conc. μg/L	SD all NH3conc μg/L
1 24h	8	753.0	58.9	726.9	73.5
2 24h	8	648.0	56.6
3 24h	8	779.7	30.6
4 24h	6	346.3	16.5	349.7	10.9
5 24h	6	346.3	7.1
6 24h	6	356.3	11.8

Conclusions:

Based on the results, aluminum nitride is considered to be slightly soluble in water.

Executive summary:

A transformation/dissolution (T/D) test in accordance with OECD Series on Testing and Assessment No. 29 was carried out to study the potential of aluminum nitride to release metal ions into the environment. A 24-hour screening test to determine the pH of maximum aluminium release was performed at pH 6 and 8 and a loading rate of 100 mg/L. The pH screening test showed aluminium releases of 981.7 ± 12.9 µg Al/L at pH 8, while the mean release of Al at pH 6 was 76.4 ± 1.1 μg Al/L. Therefore, the full T/D test was conducted at pH 8. The acute endpoint (7 days), was determined at sample loadings 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 documented aluminum release measurements of 202.9 ± 14.8 µg Al/L, 366.0 ± 11.4 μg Al/L and 1087.1 ± 69.6 μg Al/L for 1, 10 and 100 mg/L sample loading respectively. Therefore, aluminum nitride is considered to be slightly soluble in water.

Description of key information

In a transformation/dissolution test aluminium nitride proved to be slightly soluble, releasing maximum aluminium concentrations of 1087.1 µg/L and total ammonia (NH₃) of maximally 2048 µg/L (at 100 mg/L nominal loading after 7 days).

Key value for chemical safety assessment

Water solubility:

1 087.1 µg/L

at the temperature of:

21.5 °C

Additional information

A transformation/dissolution (T/D) test in accordance with OECD Series on Testing and Assessment No. 29 was carried out to study the potential of aluminium nitride to release metal ions into the environment. A 24-hour screening test to determine the pH of maximum aluminium release was performed at pH 6 and 8 and a loading rate of 100 mg/L. The pH screening test showed aluminium releases of 981.7 ± 12.9 µg Al/L at pH 8, while the mean release of Al at pH 6 was 76.4 ± 1.1 μg Al/L. Therefore, the full T/D test was conducted at pH 8. The acute endpoint (7 days), was determined at sample loadings 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 documented aluminium release measurements of 202.9 ± 14.8 µg Al/L, 366.0 ± 11.4 μg Al/L and 1087.1 ± 69.6 μg Al/L for 1, 10 and 100 mg/L sample loading respectively. Therefore, aluminium nitride is considered to be slightly soluble in water.