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Toxicological information

Basic toxicokinetics

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Administrative data

Endpoint:
basic toxicokinetics
Type of information:
experimental study
Adequacy of study:
key study
Study period:
4 January 2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study not conducted to GLP but conducted in accordance with generally accepted scientific principles based on a standard OECD method.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Objective of study:
other: determination of the behaviour of the substance at low pH in order to provide comparison with the similar substance AZC.
Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
other: OECD 111
Deviations:
yes
Remarks:
The study was conducted at pH 2 and pH 4. Due to the very fast hydrolysis of the substance under acidic conditions and the slow release of CO2 from the solution, it was decided not to perform kinetic measurements.
Principles of method if other than guideline:
The purpose of this study was to determine the hydrolysis under evolution of carbon dioxide of Potassium Zirconium Carbonate (KZC) at pH 2.00
and pH 4.00. Gas absorption on sodium hydroxide (on a support material) is used to determine the cleavable amount of carbon dioxide from KZC in acidic solution at two different pH values.
GLP compliance:
no

Test material

Constituent 1
Reference substance name:
Potassium Zirconium Carbonate
IUPAC Name:
Potassium Zirconium Carbonate
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder

Results and discussion

Any other information on results incl. tables

RESULTS,  pH 2.00

 

Sample
weight
as is

Acid
buffer
solution
volume

Temperature
used to release
the CO2from
the solution

Reac-
tion
time

pH at the end
of reaction
(at room
temperature)

CO32-con-
tent in KZC
(according
to supplier)

CO2
found in
absorption
tube

CO32-calculated
from CO2
found

CO32-
content
in KZC sample

[g]

[mL]

[°C]

[min]

 

 [%]

[g]

[g]

[%]

0.3061

250.0

25

40

2.00

44.9

0.0956

0.1304

42.59

0.3068

250.0

25

40

2.00

44.9

0.0960

0.1309

42.67

0.3070

250.0

25

40

2.00

44.9

0.0954

0.1301

42.37

0.3110

250.0

25

40

2.00

44.9

0.0975

0.1329

42.75

The amount of CO2 found after hydrolysis is equal to a carbonate content of 42.6 ± 0.1 % in KZC tested substance.

RESULTS,  pH 4.00

 

Sample
weight
as is

Acid
buffer
solution
volume

Temperature
used to release
the CO2from
the solution

Reac-
tion
time

pH at the end
of reaction
(at room
temperature)

CO32-con-
tent in KZC
(according
to supplier)

CO2
found in
absorption
tube

CO32-calculated
from CO2
found

CO32-
content
in KZC sample

[g]

[mL]

[°C]

[min]

 

 [%]

[g]

[g]

[%]

0.3043

250.0

65 - 70

80

4.10

44.9

0.0919

0.1253

41.18

0.3068

250.0

65 - 70

80

4.10

44.9

0.0990

0.1350

44.00

0.3085

250.0

65 - 70

80

4.10

44.9

0.0938

0.1279

41.46

 

The amount of CO2 found after hydrolysis is equal to a carbonate content of 42.2 ± 1.3 % in KZC tested substance.

IDENTIFICATION OF HYDROLYSIS PRODUCTS

One hydrolysis product of KZC is carbon dioxide. The remaining zirconium compounds are not identified.

Applicant's summary and conclusion

Conclusions:
The experiments at pH 2 and 4 show fast hydrolysis of KZC. This hydrolysis is observed via effervescence during addition of the acidic buffer solution. The fast hydrolysis and the fact that the CO2 release from the solution is slow did not allow kinetic information to be obtained. The experiments showed that the CO2 released during the hydrolysis reaction corresponds to the carbonate content of KZC as given by the supplier. Based on this information, it can be concluded that KZC undergoes complete degradation under acidic conditions in a few minutes.
Executive summary:

A study was conducted to investigate the hydrolysis of the test material under acidic conditions, broadly in accordance with OECD guideline 111.

Gas absorption on sodium hydroxide (on a support material) is used to determine the cleavable amount of carbon dioxide from KZC in acidic solution at two different pH values.

The experiments at pH 2 and 4 show fast hydrolysis of KZC. This hydrolysis is observed via effervescence during addition of the acidic buffer solution. The fast hydrolysis and the fact that the CO2 release from the solution is slow did not allow kinetic information to be obtained. The experiments showed that the CO2 released during the hydrolysis reaction corresponds to the carbonate content of KZC as given by the supplier. Based on this information, it can be concluded that KZC undergoes complete degradation under acidic conditions in a few minutes.