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Toxicological information

Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was conducted prior to availability of the appropriate OECD TG and OPPTS testing guidelines; however, it is well documented and is scientifically acceptable. Hence, it is rated klimisch 2 and was identified as a key study and .
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1980

Materials and methods

Test guideline
Guideline:
other:
Principles of method if other than guideline:
Rats were exposed to the vapor concentrations of the test material in a dynamic air-flow inhalation exposure system for 4 hours.
GLP compliance:
no
Test type:
acute toxic class method
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Dibromomethane
EC Number:
200-824-2
EC Name:
Dibromomethane
Cas Number:
74-95-3
Molecular formula:
CH2Br2
IUPAC Name:
dibromomethane
Details on test material:
unspecified purity, DBM

Test animals

Species:
rat
Strain:
other: albino CD
Sex:
male
Details on test animals or test system and environmental conditions:
Humidity, temperature, flow-rate and static pressure were measured and recorded.

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure:
nose only
Vehicle:
air
Details on inhalation exposure:
in a dynamic air-flow inhalation exposure system for 4 hours
Analytical verification of test atmosphere concentrations:
yes
Remarks:
using FIDAMAT, Siemens A.G., Germany
Duration of exposure:
4 h
Concentrations:
22.3, 22.2, 22.1, 21.7 and 21.4 mg/m3
No. of animals per sex per dose:
Five groups of 12 male
Control animals:
yes
Details on study design:
At termination of exposure, rats were immediately removed from their individual chambers and observed for any specific symptoms and/or changes in behavior.
Statistics:
Statistical analysis was limited to calculation of means and standard deviations of body weight and body weight change.

Results and discussion

Preliminary study:
n/a
Mortality:
none
Clinical signs:
other: Animals seemed seriously incapacitated in their spontaneous motor activity as exhibited by slow breathing, uncoordinated and atactic walk, continuous tremor, and excessive preening. All these effects wore off within about 3 hours when most of the exposed
Body weight:
Immediately upon removal from the exposure chambers, animals lost weight of ~5.4g apparently due to excessive fluid excretion.
Gross pathology:
No gross necropsy findings were observed
Other findings:
No further information

Any other information on results incl. tables

No further information

Applicant's summary and conclusion

Conclusions:
In the 4 hours inhalation study in rats receiving 22.3, 22.2, 22.1, 21.7 and 21.4 mg/m3 DBM in a dynamic air-flow inhalation exposure system, no mortalities had occurred and no lasting pathological changes were seen at 18 and 20 days post treatment. Based on the results LC50> 22.3mg/m3 can be concluded.
Executive summary:

Five groups of 12 male albino CD rats were exposed to the following vapor concentrations of the test material (unspecified purity, DBM): 22.3, 22.2, 22.1, 21.7 and 21.4 mg/m3 in a dynamic air-flow inhalation exposure system for 4 hours. Humidity, temperature, flow-rate and static pressure were measured and recorded. At termination of exposure, rats were immediately removed from their individual chambers and observed for any specific symptoms and/or changes in behavior.

Immediately upon removal from the exposure chambers, animals lost weight of ~5.4g apparently due to excessive fluid excretion. They seemed seriously incapacitated in their spontaneous motor activity as exhibited by slow breathing, uncoordinated and atactic walk, continuous tremor, and excessive preening. All these effects wore off within about 3 hours when most of the exposed animals were found in deep sleep. On the following morning, the treated rats seemed exactly like the control ones. At the end of 18 to 20 days observation period, animals were autopsied. No obvious pathological differences in internal organs could be detected between experimental and control animals. Based on the outcome of this study, LC50> 22.3mg/m3 can be concluded.

The study was well documented and is scientifically acceptable. Hence, it was identified as a key study and was graded klimisch 2.