Silicic acid, aluminum sodium salt

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Oct. 25, 2021 - Feb. 25, 2022; experimental phase: Oct. 27 - Dec. 20, 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

transformation / dissolution of metals and inorganic metal compounds

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Oct. 25, 2021 - Feb. 25, 2022; experimental phase: Oct. 27 - Dec. 20, 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same 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

Version / remarks:

Jul. 23, 2001

Deviations:

yes

Remarks:

mass balance (%) was not performed during the full test for 1 mg/L as the determination was not precise

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Remarks:

measurement of Silicon and Aluminium per ICP-OES in aqueous media

Specific details on test material used for the study:

Name: Sodasil P-95
Batch no.: 937201AS_023301AS
CAS no.: 1344-00-9
Composition Silicic acid, aluminum sodium salt: 100%
Storage: room temperature (20 ± 5 °C)
Expiry date: 30. Jul. 2022
Stability: stable under storage conditions
Appearance: white powder
Purity: 100%
Homogeneity: homogeneous
Production date: 10. Sep. 2019
EC no.: 215-684-8
Molecular formula: nSiO2*mAl2O3*zNa2O
Molecular weight: unknown
Vapour pressure: 13.3 hPa at 1732 °C

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

64.7 µg/L

Element analysed:

silicon

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

3.48 µg/L

Element analysed:

aluminium

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Details on results:

In this study, the maximum concentration of total dissolved Si and Al was determined in order to identify compounds of SODASIL P-95 which undergo either dissolution or rapid transformation.
The method validation of Si was performed during the study 21080202G989 and the results were also be used in this study. The method validation for the determination of Al in buffer solutions was performed during this study.
The calibration was performed using the certified Al stock solution (1000 mg/L nominal). All validation conditions for the range of 3 – 50 µg/L Al in pH 8.5 buffer solution were ful-filled except the accuracy in pH 5.5 and pH 7.0 buffer solutions. The accuracy was out-side 70 – 120 % of the nominal values. Therefore, the calibration of Al was additionally performed in each buffer solution.
The correlation coefficient r was > 0.99 and the accuracy values of the calibration stand-ards lay in the demanded ranges 100 ± 15 % and 100 ± 20 % (low concentration) of each calibration.
All accuracy values lay in the demanded range of 70 – 110 % after recalculation of the accuracy in pH 5.5 and pH 7.0 buffer solutions using the corresponding calibration function in the respective buffer. As the values lay outside the range 100 ± 5 %, the mean recovery rates were taken into account in the calculation of Al concentrations in the respective buffer solution. The condition for precision “RSD ≤ 20 % per level” was fulfilled for all media and levels.
During the screening test, the adjustment of pH value in the range of 5.5 ± 0.2 in pH 5.5 buffer solution was not possible as the test item has changed the pH value of the buffer (5.90 – 6.31). The highest concentration of Si was measured in pH 8.5 buffer solution. Therefore, pH 8.5 buffer solution was chosen for the reproducibility test. The concentration of Al was below the LOQ (< 3 µg/L Al).
The reproducibility test was performed with 100 mg/L test item over a period of 24 hours. Five vessels were prepared; each flask was measured in triplicate. A within-vessel variation of max. 10% and a between-vessel variation of max. 20% was demanded. These conditions were fulfilled. The mean concentration of Si in all flasks was stated as 384.0 µg/L Si.
The full test was performed with 1 mg/L nominal load (three replicates) over a period of 28 days with samplings after 2 h, 6 h, 1 d, 4 d, 7 d, 14 d, 21 d and 28 d. Two flasks were prepared as blanks without addition of test item. Dependency of measured concentrations of Si on time was linear during the whole test. The measured concentration of Al was below the LOQ (< 3 µg/L Al) in each flask at each sampling point except on day 28.
Both conditions RSD ≤ 10 % (within-vessel) and ≤ 20 % (between-vessel) were fulfilled for Si in all flasks at each sampling point and Al on day 28 during the full test. On day 1, the within-vessel variation of Si was > 10 % in the flask 3 as one replicate showed the concentration of Si < 10 µg/L.

The following concentrations of Si and Al were stated on day 28:
1 mg/L nominal: 64.7 µg/L Si; 3.48 µg/L Al.

No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.

Conclusions:

The following concentrations of Si and Al were stated for 1 mg/L nominal load after 28 d:

64.7 µg/L Si,
3.48 µg/L Al

at 20.8 ± 0.8 °C and pH 8.41 ± 0.09.

Executive summary:

This study was performed in order to determine the transformation and/or dissolution of Sodasil P-95 via measurement of Silicon (Si) and Aluminium (Al) per ICP-OES in aqueous media. The full test was performed with 1 mg/L nominal load (three replicates) over a period of 28 days with samplings after 2 h, 6 h, 1 d, 4 d, 7 d, 14 d, 21 d and 28 d. The following concentrations of Si and Al were stated on day 28 with 1 mg/L nominal load: 64.7 µg/L Si and 3.48 µg/L Al.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Series on Testing and Assessment No. 29

Version / remarks:

Jul. 23, 2001

Deviations:

yes

Remarks:

mass balance (%) was not performed during the full test for 1 mg/L as the determination was not precise

GLP compliance:

yes (incl. QA statement)

Type of study / information:

transformation / dissolution:
- flask method
- measurement of Silicon and Aluminium per ICP-OES in aqueous media

Test material

Test material information

Constituent 1

Reference substance name:

Silicic acid, aluminum sodium salt

EC Number:

215-684-8

EC Name:

Silicic acid, aluminum sodium salt

Cas Number:

1344-00-9

Molecular formula:

nSiO2*mAl2O3*zNa2O n = 2-4; m = 0.12-3.20; z = 0.11-4.5

IUPAC Name:

aluminium(3+) sodium bis(oxosilanebis(olate))

Test material form:

solid: nanoform, no surface treatment

Remarks:

crystalline-free

Specific details on test material used for the study:

Name: Sodasil P-95
Batch no.: 937201AS_023301AS
CAS no.: 1344-00-9
Composition Silicic acid, aluminum sodium salt: 100%
Storage: room temperature (20 ± 5 °C)
Expiry date: 30. Jul. 2022
Stability: stable under storage conditions
Appearance: white powder
Purity: 100%
Homogeneity: homogeneous
Production date: 10. Sep. 2019
EC no.: 215-684-8
Molecular formula: nSiO2*mAl2O3*zNa2O
Molecular weight: unknown
Vapour pressure: 13.3 hPa at 1732 °C

Results and discussion

Any other information on results incl. tables

In this study, the maximum concentration of total dissolved Si and Al was determined in order to identify compounds of SODASIL P-95 which undergo either dissolution or rapid transformation.
The method validation of Si was performed during the study 21080202G989 and the results were also be used in this study. The method validation for the determination of Al in buffer solutions was performed during this study.
The calibration was performed using the certified Al stock solution (1000 mg/L nominal). All validation conditions for the range of 3 – 50 µg/L Al in pH 8.5 buffer solution were ful-filled except the accuracy in pH 5.5 and pH 7.0 buffer solutions. The accuracy was out-side 70 – 120 % of the nominal values. Therefore, the calibration of Al was additionally performed in each buffer solution.
The correlation coefficient r was > 0.99 and the accuracy values of the calibration stand-ards lay in the demanded ranges 100 ± 15 % and 100 ± 20 % (low concentration) of each calibration.
All accuracy values lay in the demanded range of 70 – 110 % after recalculation of the accuracy in pH 5.5 and pH 7.0 buffer solutions using the corresponding calibration function in the respective buffer. As the values lay outside the range 100 ± 5 %, the mean recovery rates were taken into account in the calculation of Al concentrations in the respective buffer solution. The condition for precision “RSD ≤ 20 % per level” was fulfilled for all media and levels.
During the screening test, the adjustment of pH value in the range of 5.5 ± 0.2 in pH 5.5 buffer solution was not possible as the test item has changed the pH value of the buffer (5.90 – 6.31). The highest concentration of Si was measured in pH 8.5 buffer solution. Therefore, pH 8.5 buffer solution was chosen for the reproducibility test. The concentration of Al was below the LOQ (< 3 µg/L Al).
The reproducibility test was performed with 100 mg/L test item over a period of 24 hours. Five vessels were prepared; each flask was measured in triplicate. A within-vessel variation of max. 10% and a between-vessel variation of max. 20% was demanded. These conditions were fulfilled. The mean concentration of Si in all flasks was stated as 384.0 µg/L Si.
The full test was performed with 1 mg/L nominal load (three replicates) over a period of 28 days with samplings after 2 h, 6 h, 1 d, 4 d, 7 d, 14 d, 21 d and 28 d. Two flasks were prepared as blanks without addition of test item. Dependency of measured concentrations of Si on time was linear during the whole test. The measured concentration of Al was below the LOQ (< 3 µg/L Al) in each flask at each sampling point except on day 28.
Both conditions RSD ≤ 10 % (within-vessel) and ≤ 20 % (between-vessel) were fulfilled for Si in all flasks at each sampling point and Al on day 28 during the full test. On day 1, the within-vessel variation of Si was > 10 % in the flask 3 as one replicate showed the concentration of Si < 10 µg/L.

The following concentrations of Si and Al were stated on day 28:
1 mg/L nominal load: 64.7 µg/L Si; 3.48 µg/L Al

No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.

Applicant's summary and conclusion

Conclusions:

The following concentrations of Si and Al were stated for 1 mg/L nominal load after 28 d:

64.7 µg/L Si,
3.48 µg/L Al

at 20.8 ± 0.8 °C and pH 8.41 ± 0.09.

Executive summary:

This study was performed in order to determine the transformation and/or dissolution of Sodasil P-95 via measurement of Silicon (Si) and Aluminium (Al) per ICP-OES in aqueous media. The full test was performed with 1 mg/L nominal load (three replicates) over a period of 28 days with samplings after 2 h, 6 h, 1 d, 4 d, 7 d, 14 d, 21 d and 28 d. The following concentrations of Si and Al were stated on day 28 with 1 mg/L nominal load: 64.7 µg/L Si and 3.48 µg/L Al.