Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: All information on this study is derived from the review article BUA Report 85, as the complete study report is not at hand. The testing laboratory report no. is 6690-68/04

Data source

Reference
Reference Type:
review article or handbook
Title:
BUA Report 85, Ref. Hazleton 1991
Author:
Beratergremium für umweltrelevante Altstoffe der Gesellschaft Deutscher Chemiker (BUA)
Year:
1992
Bibliographic source:
Hirzel Verlag, Stuttgart

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
not specified
Remarks:
as only the respective review article is at hand
GLP compliance:
not specified
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
other: CD(SD)BR-strain
Sex:
male/female

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
nose/head only
Vehicle:
other: unchanged (no vehicle)
Analytical verification of test atmosphere concentrations:
no
Duration of exposure:
4 h
Concentrations:
gravimetrically determined mean aerosol concentration: 2.485 mg/L air = 2485 mg/m3
No. of animals per sex per dose:
5
Control animals:
not specified

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
ca. 2.485 mg/L air
Exp. duration:
4 h
Remarks on result:
other: The dust aerosol concentration of 2.485 mg/L air was gravimetrically determined. 95% CL could not be determined, as only 1 aerosol concentration was tested.
Mortality:
50 % (sex was not specified in the review article)
Clinical signs:
other: stringy fur, apathy, cool skin surface, bodily discolouring and respiratory distress lasting in a few animals until the second observation week.
Body weight:
Body weight gain was reduced in the survivors during observation week 1 (post inhalation exposure).
Gross pathology:
Macroscopic alterations in upper respiratory tract and lungs in decedent animals. No noteworthy findings in the survivors at 14 days post inhalation exposure.
Other findings:
Increased lung weights in decedent animals.

Applicant's summary and conclusion

Interpretation of results:
harmful
Remarks:
Migrated information Criteria used for interpretation of results: expert judgment
Conclusions:
Head-nose inhalation exposure of male and female rats to 2,3,5,6-tetrachloro-1,4-benzoquinone for 4 hours at a gravimetrically determined mean dust aerosol concentration of 2.485 mg/L air led to the premature death of 5 of 10 animals. Therefore, 2.485 mg/L air was assumed to represent an approximate LC50 (4 hours) for 2,3,5,6-tetrachloro-1,4-benzoquinone.
Executive summary:

2,3,5,6-tetrachloro-1,4-benzoquinone was tested for inhalation toxicity similar to OECD Guideline 403. Reliability grade 4 (reliability not assignable) was assigned to the study, as all information on this study was attained only from a review article. Over a period of 4 hours, five male and five female rats were exposed nose/head only to the test substance at a mean gravimetrically determined dust aerosol concentration of 2.485 mg/L air. The exposure was followed by a 14-day observation period. Mortality, bodyweights, clinical signs and gross necropsy findings were recorded and lung weights were determined. The attained "average particle diameter" of the generated dust aerosol [(probably meaning "average Mass Median Aerodynamic Diameter (MMAD)"] of 1.76 µm was well within the range of 1 to 4 µm MMAD recommended for acute inhalation toxicity testing in rats by various technical guidelines, e.g. EPA OPPTS 870.1300. Therefore, adequate exposure to the test substance over the whole respiratory tract can be assumed.

 

Exposure to the test substance induced 50% mortality, i.e. the premature death of 5 of 10 animals. Clinical signs comprised stringy fur, apathy, cool skin surface, bodily discolouring and respiratory distress lasting in a few animals until the second observation week. Retardation of body weight gain was evident in the survivors during observation week 1. Necropsy revealed alterations in the upper respiratory tract and lungs as well as increased lung weights in decedent animals, but no noteworthy findings were evident in the survivors at their scheduled necropsy 14 days post exposure.

 

In view of the 50% mortality attained, 2.485 mg/L air was assumed to represent an approximate LC50(4 hours) for 2,3,5,6-tetrachloro-1,4-benzoquinone.