Aluminum sodium oxide

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

n/a

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards, well documented and acceptable for assessment

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OECD (2001) Series on testing and assessment number 29. Guidance document on transformation/dissolution of metals and metal compounds in aqueous media

Principles of method if other than guideline:

The transformation / dissolution of aluminium compounds were tested in accordance to the draft OECD Transformation/Dissolution protocol. The experimental design includes refinements, agreed by the ad hoc OECD Validation Management Group (VMG), as described in the Standard Operating Procedures prepared by CANMET and LISEC. Samples of a commercially available Aluminium Hydroxide were tested at 1 and 100 mg/L loadings at pH 6 and 8, for up to 28 days at a stirring rate of 100 rpm. The results can be used to compare with existing ecotoxicity data and to establish the hazard classification of the tested substance.

GLP compliance:

not specified

Type of study / information:

Transformation / dissolution study

Test material

Test material information

Constituent 1

Reference substance name:

Aluminium hydroxide

EC Number:

244-492-7

EC Name:

Aluminium hydroxide

Cas Number:

21645-51-2

Molecular formula:

AlH3O3

IUPAC Name:

aluminum trihydroxide

Details on test material:

- Name of test material (as cited in study report): Aluminiumhydroxid (dry), Al(OH)3/SH-20 Muster from AOS Aluminiumoxid Stade, Germany
- Analytical purity: pure
- Composition of test material, percentage of components: 65.1 ± 0.3% (dry weight as Al2O3)
- Purity test date: 01.06.2006
-Particle distribution ( <45µm): 2.8±1% (ISO 13320-1)

Results and discussion

Any other information on results incl. tables

Preliminary assay:

Since dissolved aluminium is prone to suffer changes in solubility with time, a preliminary experiment was set up to determine the effect of the sitting time after the sample is taken from the Dissolution /Transformation (D/T) test and the amount of dissolved metal in solution. 100 mg/L of Al2O3 were subject to 24h D/T test, pH 6 and 8 at 100 RPM. After the 24h a total of 30 samples of 10 mL per pH were taken from the vessel, filtered and acidified. The samples were let to sit for aluminiun determination for 0, 8, 24, 48 and 72 hour.

At both pHs the amount of dissolved aluminium remains constant after the 8 hours sitting period. Therefore, in Dissolution /Transformation study all the samples were measure in a period of 24 to 48 hours after the samples were taken from the test.

Temperature, Oxygen and pH control:

The temperature of the test media varied between 18.8 and 24 °C. The O2 concentrations of the test media varied between 7.19 and 8.37 mg O2/L. The pH of the media varied between 6.04 and 6.35 (pH 6 media) and 7.63 and 8.07 (pH 8 media), temperature between 20 & 25 °C, dissolved oxygen concentration above 70% of its saturation in air and pH around 0.2 units difference from the desired pH.

Dissolution Transformation Results:

Aluminium Hydroxide was submitted to dissolution/transformation test at pHs 6 and 8 at two loadings, 1 mg/L for 28 days and 100 mg/L for 7 days. At pH 6 Aluminium Hydroxide, in all tested condition, showed very low release of dissolved metal (see table 1). The amounts of metal released by the samples and the blanks were undistinguishable. The same was found for Aluminium hydroxide at pH 8.0, at high and low loading, where the amounts of metal released by the samples were at blanks levels.

 

 Table 1: Summary of the short term (7 days) and long term (28 days) transformation/dissolution data obtained for Al(OH)3, at different loadings and pHs. Blank values are included but not subtracted.

Loading	pH	Endpoint	Al, µg/L	St. Des.	CV, %
Blanks	6	7 days	2	0.00	0
1 mg/L	6	7 days	3	1.86	72
1 mg/L	6	28 days	4	2.07	55
100 mg/L	6	7 days	2	1.67	79
Blanks	8	7 days	3	0.00	0
1 mg/L	8	7 days	3	0.49	15
1 mg/L	8	28 days	3	0.00	0
100 mg/L	8	7 days	4	1.39	40