Bromomethane

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Materials and methods

Test guideline

Qualifier:

according to guideline

Principles of method if other than guideline:

The test procedure followed guidelines based upon the up-and-down method described by Dixon, W.J. and Massay, F.J. in Introduction to Statistical Analysis, 3rd Ed, McGraw Hill, New York, 1969, pgs. 380-389 and Bruce, R.D. in “An Up-and-Down Procedure for Acute Toxicity Testing”, Fundam. Appl, Tox 5, 151-197, 1985.
This study differs from the prescribed method outlined in the EU Directive (EEC B2) in that the exposure time was for seven hours as opposed to the recommended 4 hours. Also, this study did not establish an LD50.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Bromomethane

EC Number:

200-813-2

EC Name:

Bromomethane

Cas Number:

74-83-9

Molecular formula:

CH3Br

IUPAC Name:

bromomethane

Details on test material:

Methyl Bromide; Batch No. SLV; Purity: 100%.

Test animals

Species:

dog

Administration / exposure

Details on inhalation exposure:

The first part of this study (Part A), using an up-and-down procedure, evaluated the maximum tolerated seven-hour exposure level in dogs from a series of single, seven-hour, whole-body inhalation exposures. Physical observations were performed and body weights were measured daily.
The second part of the study (Part B), evaluated in dogs the maximum tolerated exposure level and toxicity associated with four consecutive daily seven hour exposures. Physical observations, body weights, haematology and clinical chemistry parameters were evaluated in all survivors. Animals were sacrificed, selected organs were weighed and organ/body postmortem examinations were conducted. Microscopic examinations were conducted on selected organs from the dogs utilized in part B of the study.

Results and discussion

Preliminary study:

In study part A, adverse clinical signs were observed after several hours of exposure, and the time of appearance was dose-related (they appeared earlier at higher doses).
In study part B, at 268 and 283 ppm Methyl Bromide, adverse clinical signs appeared on the second day of exposure. At 156 ppm, they appeared on the third day. Therefore, the toxic effect appeared cumulative. The maximum exposure level in dogs for up to 4 daily seven-hour exposures was between 55 to 156 ppm. However, because of this apparent cumulative effect, it is difficult to estimate an exposure level that the dogs would be able to tolerate during a 28 day or one year exposure.

Effect levels

Sex:

male/female

Dose descriptor:

other: max. tolerable conc.

Effect level:

> 55 - < 156 ppm

Based on:

test mat.

Exp. duration:

4 d

Remarks on result:

other: 7 h exposure/day

Clinical signs:

other: Haematological evaluations indicated that HBG (haemoglobin), HCT (hematocrit), RBC (erythrocytes) and WBC (white blood cells) might have increased with Methyl Bromide exposure.

Applicant's summary and conclusion

Conclusions:

The maximum exposure level in dogs for up to 4 daily, seven-hour exposures was between 55 to 156 ppm.