Registration Dossier

Administrative data

Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
key study
Study period:
16/04/2018 - 31/08/2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 112 (Dissociation Constants in Water)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): Bismuth hydroxide nitrate oxide
- Molecular formula (if other than submission substance): Bi5O(OH)9(NO3)4
- Molecular weight (if other than submission substance): 1461.99 g/mol
- Substance type: pure substance
- Physical state: solid, white, cloddy powder

Specific details on test material used for the study:
Batch/Lot Number: 2018000867

Results and discussion

Dissociating properties:
not determined
Remarks:
Dissociation constant of the test item could not be determined under the conditions of this test.

Any other information on results incl. tables

Dissociation constant of the test item could not be determined under the conditions of this test. It was considered that the low solubility of the test item prevented the titration method from being feasible (the titration method is not suitable for low solubility substances).

Applicant's summary and conclusion

Conclusions:
Dissociation constant cannot be calculated because of low solubility. As the substance does not dissolve, it cannot dissociate in water.
Executive summary:

The dissociation of a chemical in water is of importance in assessing its impact upon the environment. It governs the form of the substance which in turn determines its behaviour and transport. It may affect the adsorption of the chemical on soils and sediments and adsorption into biological cells.

According to the OECD No. 112 guideline, three methods are available for dissociation constant determination. As the test item had no light absorption properties, the spectrophotometric method could not be used. As approximately 0.1 M solution of the test item was not achievable, the conductometry method could not be used either. Therefore, the titration method was applied.

Dissociation constant of the test item could not be determined under the conditions of this study. It was considered that the low solubility of the test item prevented the titration method from being feasible (the titration method is not suitable for low solubility substances).