Cerium terbium magnesium undecaaluminum nonadecaoxide (hexagonal) ((Ce, Tb)MgAl11O19) and aluminium oxide (Al2O3) from calcination of Al2O3, CeO2, MgO and Tb4O7

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the physicochemical properties of the substance indicate that it can be expected to have a low potential for adsorption

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
- The HPLC screening method (OECD 121) is technically not feasible to conduct because this inorganic substance is insoluble in water and is not soluble in any solvent commonly used for chromatography. Even if it would be possible to dissolve the substance as a whole and to elute it over the stationary phase, detection with a regular HPLC detector would not be possible.
This reasoning is in line with ECHA Guidance document R.7a, p. 152, which states that the HPLC method: OECD TG 121; EU C.19 “may not be suitable for…inorganic compounds”.
- The Batch Equilibrium Method (OECD 106) is not an information requirement for the Annex VIII tonnage band and was therefore not considered as alternative. Also, in view of the insolubility of the substance in water, it is considered technically not feasible to conduct the OECD 106 study.
Based on this information, the substance is not expected to have potential for adsorption.

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 8, 2011 - January 11, 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

(1995)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

(2008)

Deviations:

no

GLP compliance:

yes

Type of method:

column elution method

Water solubility:

< 0.5 other: mg Al/L

Temp.:

20 °C

pH:

6.5 - 6.8

Remarks on result:

other: Concentration of Aluminium (Al) in the with test substance saturated aqueous phase.

Water solubility:

< 1 other: μg Ce/L

Temp.:

20 °C

pH:

6.5 - 6.8

Remarks on result:

other: Concentration of Cerium (Ce) in the with test substance saturated aqueous phase.

Water solubility:

< 0.1 other: mg Mg/L

Temp.:

20 °C

pH:

6.5 - 6.8

Remarks on result:

other: Concentration of Magnesium (Mg) in the with test substance saturated aqueous phase.

Water solubility:

< 1 other: μg Tb/L

Temp.:

20 °C

pH:

6.5 - 6.8

Remarks on result:

other: Concentration of Terbium (Tb) in the with test substance saturated aqueous phase.

Details on results:

- With all test samples (n=10) of both flowrates and corresponding blanks the response of the elements was below the element response of the lowest calibration solution.
- The column material was checked by chemical analysis. It was demonstrated that the column material contained the test substance.

Preliminary test

Element	Water solubility
Al	< 0.5 mg/l (*)
Ce	91.1 µg/l
Mg	< 0.1 mg/l (*)
Tb	145 µg/l (**)

(*) Based onthe response of the lowest calibration standard and taking the diluting factor of the sample into account.

(**) Obtained by extrapolation of the calibration curve.

Conclusions:

The column elution method was applied for the determination of the water solubility of the substance in accordance with OECD 105 (1995), EU Method A.6 (2008) and according to GLP principles. Chemical analysis was performed on Aluminium, Cerium, Magnesium and Terbium. With all test samples of both flowrates and corresponding blanks the response of the elements was below the element response of the lowest calibration solution. As with all analysed samples the response of all the elements was below 0.1 mg/L, below 0.5 mg/L or below 1 µg/L, the substance is considered to be insoluble in water.