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Physical & Chemical properties

Water solubility

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Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
21 June 2016 - 26 January 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
column elution method
Test material information:
Composition 1
Water solubility:
2.8 mg/L
Conc. based on:
element (dissolved fraction)
Remarks:
Gd
Temp.:
20 °C
pH:
4
Remarks on result:
other: Mean at flow rates 12.5 mL/h and 25 mL/h.
Water solubility:
5.1 mg/L
Conc. based on:
test mat. (dissolved fraction)
Remarks:
Result calculated based on dissolved Gd measurements
Temp.:
20 °C
pH:
4
Remarks on result:
other: Mean at flow rates 12.5 mL/h and 25 mL/h.
Water solubility:
0.6 mg/L
Conc. based on:
element (dissolved fraction)
Remarks:
Gd
Temp.:
20 °C
pH:
6.4
Remarks on result:
other: Mean at flow rates 12.5 mL/h and 25 mL/h.
Water solubility:
1 mg/L
Conc. based on:
test mat. (dissolved fraction)
Remarks:
Result calculated based on dissolved Gd measurements
Temp.:
20 °C
pH:
6.4
Remarks on result:
other: Mean at flow rates 12.5 mL/h and 25 mL/h.
Key result
Water solubility:
0.7 mg/L
Conc. based on:
element (dissolved fraction)
Remarks:
Gd
Temp.:
20 °C
pH:
7
Remarks on result:
other: Mean at flow rates 12.5 mL/h and 25 mL/h
Key result
Water solubility:
1.3 mg/L
Conc. based on:
test mat. (dissolved fraction)
Remarks:
Result calculated based on dissolved Gd measurements
Temp.:
20 °C
pH:
7
Remarks on result:
other: Mean at flow rates 12.5 mL/h and 25 mL/h.
Water solubility:
0.7 mg/L
Conc. based on:
element (dissolved fraction)
Remarks:
Gd
Temp.:
20 °C
pH:
9
Remarks on result:
other: Mean at flow rates 12.5 mL/h and 25 mL/h.
Water solubility:
1.3 mg/L
Conc. based on:
test mat. (dissolved fraction)
Remarks:
Result calculated based on dissolved Gd measurements
Temp.:
20 °C
pH:
9
Remarks on result:
other: Mean at flow rates 12.5 mL/h and 25 mL/h.
Details on results:
Results were validated by:
- Linearity validation: The analysis showed a good linearity of the method (r > 0.99)
- Accuracy validation: Results in dilution mixture showed a good accuracy which indicates acceptable data (recoveries ranged between 75 and 125%).
- Repeatability validation: The results indicated a good precision of the data.
- Specificity: The intensity (CPS) of blank samples measured was negligible or similar to solvent intensity.
- Limit of quantification: For the method in solution the LOQ was set at 1 ng/mL.
- Limit of detection: The LOD was found to be 0.1 ng/mL.
Conclusions:
The water solubility (expressed as gadolinium oxalate concentration) of the test substance was determined to be 5.1 mg/L, 1.0 mg/L, 1.3 mg/L and 1.3 mg/L at pH 4, 6.4, 7 and 9, respectively, and was calculated from the measured gadolinium content in water which was 2.8 mg/L at pH 4, 0.6 mg/L at pH 6.4, and 0.7 mg/L at pH 7 and 9. Results of this study can be considered reliable without restriction.


Description of key information

In a GLP study (Klimisch 1, Jean-Baptiste, 2017) based on the OECD 105 and EC A.6 test guidelines, the water solubility of gadolinium oxalate was determined to be 5.1 mg/L at pH 4, 1.0 mg/L at pH 6.4, and 1.3 mg/L at pH 7 and pH 9, expressed as gadolinium oxalate content in water at 20°C and extrapolated from the measured values of dissolved gadolinium which were 2.8 mg/L at pH 4, 0.6 mg/L at pH 6.4, and 0.7 mg/L at pH 7 and pH 9.

This study was assigned as key study.

Key value for chemical safety assessment

Water solubility:
1.3 mg/L
at the temperature of:
20 °C

Additional information