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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
Study period:
No data
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant, near guideline study, available as unpublished report, adequate for assessment
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1981
Report Date:
1981

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
yes
Remarks:
6 hour exposure
GLP compliance:
yes
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Dicyclopentadiene (DCPD)
- Physical state: clear colourless liquid at room temperature
- Analytical purity: ~97% endo- and ~1% cyclopentadiene

Test animals

Species:
rat
Strain:
Fischer 344
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Microbiological Associates, Walkersville, Maryland, USA
- Age at study initiation: no data
- Weight at study initiation: no data
- Fasting period before study: no
- Housing: 2 per cage in stainless steel cages
- Diet: powdered chow diet ad libitum except during exposure
- Water: ad libitum except during exposure
- Acclimation period: approximately 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature: 69-74°F
- Humidity: 30-63%
- Photoperiod: 12 hrs dark /12 hrs light

IN-LIFE DATES: no data

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure:
whole body
Vehicle:
other: air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Dicyclopentadiene vapour was generated inside a heated Pyrex tube to achieve complete vaporization while keeping temperature below the point (35°C) at which fracturing to monomer occurred.

TEST ATMOSPHERE
- Chamber concentrations of dicyclopentadiene and cyclopentadiene (CPD) were monitored by gas chromatography/flame ionization detection with detection limit of 0.05 ppm for both compounds.
Analytical verification of test atmosphere concentrations:
yes
Remarks:
by gas chromatography/flame ionization detection
Duration of exposure:
6 h
Concentrations:
Target concentrations were 50, 150, 300 and 600 ppm.
Actual exposure concentrations were 46, 130, 260 and 557 ppm.
No. of animals per sex per dose:
6
Control animals:
not specified
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations: animals were observed daily for clinical signs
- Necropsy of survivors performed: yes
Statistics:
LC50 was calculated by the method of moving averages.

Results and discussion

Effect levelsopen allclose all
Sex:
male
Dose descriptor:
LC50
Effect level:
284 ppm
95% CL:
236 - 341
Exp. duration:
6 h
Remarks on result:
other: 1536 mg/m3 air (analytical)
Sex:
female
Dose descriptor:
LC50
Effect level:
353 ppm
95% CL:
322 - 387
Exp. duration:
6 h
Remarks on result:
other: 1910 mg/m3 air (analytical)
Sex:
male/female
Dose descriptor:
LC50
Effect level:
1 723 mg/m³ air (analytical)
Exp. duration:
6 h
Sex:
male/female
Dose descriptor:
other: NOAEC for irregular breathing, stereotypic behaviour
Effect level:
46 ppm
Remarks on result:
other: 248.74 mg/m3
Mortality:
There were mortalities in male and female rats exposed to 557 or 260 ppm. (The actual numbers of rats dying at the various exposure levels were not presented in the report).
Clinical signs:
other: Male and female rats at 557 ppm showed loss of righting reflex, impaired gait, stereotypic behaviour, laboured breathing, nasal discharge, convulsions and death. At 260 ppm, both sexes showed stereotypic behaviour, respiratory difficulty and nasal dischar
Body weight:
No data
Gross pathology:
There were no gross pathological effects noted at necropsy

Any other information on results incl. tables

Incidence of mortality following single 6-hour inhalation exposure

Target Concentration (ppm)

Dead/dosed

Comment

 

male

female

 

600

6/6

6/6

Males: One died during exposure. 3 died immediately post-exposure. 2 found dead on the day after exposure.

Females: All found dead on the day after exposure.

300

2/6

0/6

Males: 2 found dead the day after exposure.

150

0/6

0/6

 

50

0/6

0/6

 

 

Applicant's summary and conclusion

Interpretation of results:
toxic
Remarks:
Migrated information by inhalation Criteria used for interpretation of results: EU
Conclusions:
Following a 6 hour whole body, inhalation exposure to dicyclopentadiene vapour, the LC50 was 284 (236-341) ppm (male) and 353 (322-387) ppm (female). The results were not confounded by the fracturing of dicyclopentadiene into cyclopentadiene. The male/female 6 hour LC50 is equivalent to 1723 mg/m3.
Executive summary:

Groups of 6 male and 6 female Fischer 344 rats were exposed (whole body) to 46, 130, 260 or 557 ppm dicyclopentadiene vapour for 6 hours and then observed daily for up to 14 days. At 557 ppm, one male died during exposure, 3 died immediately post-exposure and 2 were found dead on the day after exposure; all females were found dead on the day after exposure. At 260 ppm, two males were found dead on the day after exposure, all females survived. Clinical signs included loss of righting reflex, impaired gait, stereotypic behaviour, laboured breathing, nasal discharge and convulsions. The LC50 was 284 ppm (male) and 353 ppm (female), equivalent to 1536 and 1910 mg/m3 respectively.