Dialuminium zinc tetraoxide

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 Sep 2011 - 05 Feb 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study with acceptable restrictions

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Kaiser-Friedrich-Straße 7, 55116 Mainz, Germany

Type of method:

flask method

Remarks:

according to OECD No. 29 for 28 days

Water solubility:

< 1 µg/L

Temp.:

22 °C

pH:

6

Remarks on result:

other: the concentration of Al at two loading rate (0.1 and 1 mg/L)

Water solubility:

< 1 µg/L

Temp.:

22 °C

pH:

6

Remarks on result:

other: the concentration of Zn at loading rate 0.1 mg/L

Water solubility:

6.3 µg/L

Temp.:

22 °C

pH:

6

Remarks on result:

other: the concentration of Zn at loading rate 1 mg/L

In a preliminary study, the transformation/dissolution of the test item in aqueous media at three different pH values (6.09; 7.07; 8.0, nominal), each in three flasks with one loading (100 mg/L) was tested and concentrations of Aluminium and Zinc were determined. The

highest concentration of Zinc was measured at pH 6 (370 μg/L Zn, mean). The highest concentration of Aluminium was at pH 8 (33 μg/L Al). After consultation with the sponsor, pH 6.0 was chosen for the main study based on the measured amount of Zinc.

The main study was performed with two different loading concentrations of the test item (0.1 and 1 mg/L) over a period of 28 days with samplings after 2 h, 6 h, 1 d, 2 d, 7 d, 14 d, 21 d and 28 d. Two flasks without addition of test item were tested in parallel as blanks.

In the period 2 h – 14 days, the Aluminium in all flasks could not be quantified, since the concentrations were below the LOQ of Aluminium (1 μg/L) and in the period 21 – 28 d was determined at the LOQ of Aluminium (1 μg/L) in the same flasks. Compared to the blank values, only a minimal amount dissolved Aluminium could be detected in same flasks (< 1 μg/L Al, LOQ). This result confirms the findings of the pre-test. Therefore, the concentration of Aluminium and the test item in flasks 3 – 8 was stated as:

< 1 μg/L Al at 20.0 – 23.3 °C

= < 1 μg/L * 10-6 kg/m3 (SI units)

The measured concentrations of Zinc on days 7, 14, 21 and 28 in flasks 6 – 8 (1 mg/L, nominal) were similar. Therefore, all values on days 7, 14, 21 and 28 were used in calculation of the arithmetic mean:

Concentration of Zinc on Days 7, 14, 21 and 28

Fl.	Content	Conc. on day 7 [µg/L]	Conc. on day 14 [µg/L]	Conc. on day 21 [µg/L]	Conc. on day 28 [µg/L]
4	0.1 mg/L	< 1	< 1	< 1	< 1
5	0.1 mg/L	< 1	< 1	< 1	< 1
6	1 mg/L	6.8	9.6	6.7	8.4
7	1 mg/L	4.7	4.6	3.4	4.2
8	1 mg/L	7.7	7.3	5.8	7.2
Measured Concentration of Zinc, Mean (Flasks 6, 7, 8) [µg/L]					6.3
Standard deviation (Flasks 6, 7, 8) [µg/L]					1.9
Relative Standard Deviation (Flask 6, 7, 8) [%]					29 %

The concentration of Zinc for the nominal concentration 1 mg/L test item was calculated from the measured values in the flasks 6 – 8 and was 6.3 μg/L Zn. The relative standard deviation for the values in the flasks 6 – 8 was higher than 20 % (29 %). This was considered as uncritical as the measurements of Zinc in this range (< 10 μg/L Zn) are inexact (at the LOQ of Zn) and the risk of carryover for such elements as Zinc, Iron and others is high.

Variation in measured values in the blanks (flasks 1 – 2) during the whole test confirms the risk of carryover during sampling or sample preparation in the laboratory Indikator.

Temperature had no direct influence on the measured concentrations, as variations in temperature did not correlate with variations in measured concentration.

The concentration of Zinc in the flasks 6 – 8 for the nominal concentration 1 mg/L was stated as

6.3 μg/L Zn (arithmetic mean value of three individual vessels, 24 values)

For the nominal concentration 0.1 mg/L, the concentration of Zinc lay below the LOQ of Zinc (1 μg/L):

< 1 μg/L Zn (0.1 mg/L test item nominal, mean value of two individual vessels, 16 values)

At all sampling points, the pH value lay in the range 6.0 ± 0.2. The temperature during 28 days was between 20 - 23.3 °C.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

not specified

Type of method:

flask method

Water solubility:

< 1 other: ppm

Remarks on result:

other: No information on pH and temperature.

Preliminary study

In the preliminary study, no dissolution was observed.

 

Main study

The following ICP results were submitted by the sponsor’s laboratory:

 

Element	Flask 1 (ppm)	Flask 2 (ppm)
Al	<1	<1
Zn	<1	<1

 

In the tested samples the analysed elements were < 1ppm.

Solubility result

The test substance D-Prism is virtually insoluble in water; the measured solubility in water is below 1 ppm.

 

Description of key information

The solubility of the substance is stated as <1 ppm. 
From transformation/dissolution test:
< 1 µg/L Al and Zn at nominal loading rate of 0.1 mg/L test item, at pH 6 and at 20 - 23.3 °C;
< 1 µg/L Al and 6.3 µg/L Zn at nominal loading rate of 1 mg/L test item, at pH 6 and at 20 - 23.3 °C.

Additional information

The water solubility of the test substance was determined under flask conditions according to OECD guideline 105.

A transformation /dissolution test according to OECD SERIES ON TESTING AND ASSESSMENT No. 29 was performed. The measured concentration of aluminium and zinc are very low (< 10 µg/L).