Manganese dioxide

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Method appears to have been conducted to good scientific standards, although not to GLP. However, in one part of the report it states oral dosing is via stomach intubation, but then the rest of the report appears to indicate ad libitum. It is difficult to know how an insoluble MnO2 would have been administered this way, so this lack of clarity makes it difficult to assign the results as reliable.

Data source

Reference

Reference Type:

publication

Title:

Studies on the evaluation of the toxicity of various salts of lead, manganese, platinum and palladium

Author:

Holbrook DJ, Washington ME, Leake HB and Brubaker PE

Year:

1975

Bibliographic source:

Environmental Health Perspectives, 10:95-101

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Rats were exposed to MnO2 via drinking water for an unspecified period of time. Bodyweights and food/water consumption were measured at 7 day intervals (results not reported).

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Manganese dioxide

EC Number:

215-202-6

EC Name:

Manganese dioxide

Cas Number:

1313-13-9

Molecular formula:

MnO2

IUPAC Name:

dioxomanganese

Details on test material:

- Name of test material (as cited in study report): MnO2

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

4 rats per cage, food (Purina Laboratory Chow; 56 ± 5 mg Mn/kg feed) and water available ad libitum.

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

water

Doses:

No data

No. of animals per sex per dose:

No data

Control animals:

yes

Results and discussion

Effect levels

Sex:

male

Dose descriptor:

LD50

Effect level:

> 3 480 mg/kg bw

Based on:

test mat.

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Conclusions:

The result of this study indicating an LD50 >> 3480 mg/kg for MnO2 conflicts directly with the current classification of MnO2 which indicates acutely harmful by the oral route. Given the insoluble nature of MnO2 and low bioavailability due to this, it is easier to believe that MnO2 should not be classified as acutely harmful by the oral route and there is no published data which supports this classification. Although assignment of a reliability of 1 or 2 is not possible for this study, the conclusion from this study, that MnO2 is not acutely harmful by the oral route, is very believable.