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Toxicological information

Basic toxicokinetics

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Administrative data

Endpoint:
basic toxicokinetics in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012-09-24 to 2012-12-27
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Objective of study:
bioaccessibility
Test guideline
Qualifier:
according to
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
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): Tellurium dioxide
- Substance type: inorganic
Radiolabelling:
no

Administration / exposure

Details on study design:
The objective of this study is to assess the dissolution of chemical compounds in artificial alveolar fluid.
The test media is selected to simulate relevant human-chemical interactions (as far as practical), i.e. entering the human body by inhalation. The amount dissolved of the test item is specified by the mass concentration of the substance in the test media under the applied test conditions. The total amount dissolved will be determined by measuring the total concentrations of dissolved tellurium.

Results and discussion

Bioaccessibility

Bioaccessibility testing results:
Dissolved mean tellurium concentrations in alveolar fluid at a loading of 20 mg/L were measured to be:
249.7 ± 7 mg/L after 2 hours (Te)
322.9 ± 25.4 mg/L after 5 hours (Te)
586.6 ± 21.2 mg/L after 24 hours (Te)
799.1 ± 7.3 mg/L after 72 hours (Te)

Any other information on results incl. tables

Dissolved Te concentrations in test vessels and method blanks

sample

total Te
conc.
[mg/L]

mean Te
conc.
per vessel
± range
[mg/L]

mean Te
conc.
all vessels
± SD
[mg/L]

LOD
[mg/L]

LOQ
[mg/L]

2h 1a

242.1

243.8 ± 2.3

249.7 ± 7

0.11

0.38

2h 1b

245.4

2h 2a

255.3

255.7 ± 0.5

2h 2b

256.0

 

 

 

 

 

 

5h 1a

299.8

301.0 ± 1.6

322.9 ± 25.4

0.11

0.38

5h 1b

302.1

5h 2a

345.1

344.9 ± 0.4

5h 2b

344.6

 

 

 

 

 

 

24h 1a

575.2

573.4 ± 2.6

586.6 ± 21.2

0.65

2.16

24h 1b

571.5

24h 2a

581.9

599.9 ± 25.4

24h 2b

617.8

 

 

 

 

 

 

72h 1a

801.3

803.7 ± 3.3

799.1 ± 7.3

0.65

2.16

72h 1b

806.0

72h 2a

800.1

794.5 ± 8.0

72h 2b

788.8

 

 

 

 

 

 

2h BW 1a

< LOD

 

 

0.11

0.38

2h BW 1b

< LOD

2h BW 2a

< LOD

 

2h BW 2b

< LOD

 

 

 

 

 

 

5h BW 1a

< LOD

 

 

0.11

0.38

5h BW 1b

< LOD

5h BW 2a

< LOD

 

5h BW 2b

< LOD

 

 

 

 

 

 

24h BW 1a

< LOD

 

 

0.65

2.16

24h BW 1b

< LOD

24h BW 2a

< LOD

 

24h BW 2b

< LOD

 

 

 

 

 

 

72h BW 1a

< LOD

 

 

0.65

2.16

72h BW 1b

< LOD

72h BW 2a

< LOD

 

72h BW 2b

< LOD

LODs (limit of detection) and LOQs (limit of quantification) depend on calibration range.A calibration with an optimal concentration range for samples was performed before each measurement series. Therefore theses limits vary. Three measurement series were performed to quantify Te concentrations.

In the vessels the pHs were not stable over the course of the test. At the start of the study a pH of 8.5 and 8.6 were measured in the two test vessles. After 72 hours the pH value was approx. 9.3.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): other: mean dissolved tellurium concentration in artificial alveolar fluid
The following dissolved mean tellurium concentrations were measured in artificial alveolar fluid at a loading of 20 g/L:
249.7 ± 7 mg/L after 2 hours (Te)
322.9 ± 25.4 mg/L after 5 hours (Te)
586.6 ± 21.2 mg/L after 24 hours (Te)
799.1 ± 7.3 mg/L after 72 hours (Te)


Executive summary:

A study was performed to assess the dissolution of tellurium dioxide in artificial alveolar fluid. The test media is selected to simulate relevant human-chemical interactions (as far as practical), i.e. entering the human body by inhalation.

The Test was performed on the basis of the guidance for OECD-Series on testing and assessment Number 29 and on Stopford et al., 2004.

Test conditions: Artificial alveolar fluid,one single loading of the test substance,measurements of dissolved tellurium after 2, 5, 24 and 72 hours of agitation at 37°C.

The test was performed in duplicate vessels with one single loading of the test substance, 20 g/L (10.00 g / 500 mL in vessel 1 and 2, respectively). The vessels were agitated in an incubation cabinet at 100 rpm at 37 ± 2 °C. During the test pH values were monitored,

in the vessels the pHs were not stable and always lower (0.2 – 0.3 units) in method blanks compared to pHs in test item loaded vessels.

Solved tellurium was quantified by ICP-OES.

The following dissolved mean tellurium concentrations were measured in artificial alveolar fluid:

249.7 ± 7 mg/L after 2 hours (Te)

322.9 ± 25.4 mg/L after 5 hours (Te)

586.6 ± 21.2 mg/L after 24 hours (Te)

799.1 ± 7.3 mg/L after 72 hours (Te)

The percentage of Te in TeO2 is 79.95 %. Therefore the amount of dissolved tellurium dioxide is calculated:

312.3 ± 8.8 mg/L after 2 hours (Tellurium dioxide)

403.9 ± 31.8 mg/L after 5 hours (Tellurium dioxide)

733.7 ± 26.5 mg/L after 24 hours (Tellurium dioxide)

999.4 ± 9.1 mg/L after 72 hours (Tellurium dioxide)

The maximum percentage after 72 hours is calculated to be 5 % dissolved tellurium dioxide in relation to loading.