Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1990
Report Date:
1990

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA OPP 81-3 (Acute inhalation toxicity)
Deviations:
yes
Remarks:
The relative humidity was not maintained between 40% and 60%, however no explanation for this marked deviation was provided.
GLP compliance:
yes
Test type:
other: Limit test
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: Brown particles
Details on test material:
- Name of test material (as cited in study report): MON 13900
- Substance type: Brown particles
- Analytical purity: 96.4%
- Lot/batch No.: DAY-8912-1370T

Test animals

Species:
rat
Strain:
other: Sprague Dawley Albino
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratory, Portage, MI
- Age at study initiation: Six weeks
- Weight at study initiation: Males (204±5 g), females (153±2 g)
- Housing: Individual
- Diet (e.g. ad libitum): Feed (Purina Mills Rodent Chow #5002)
- Water: Ad libitum)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.2 ± 0.8 ⁰C
- Humidity (%): 20.9 ± 0.7%
- Air changes (per hr): 87.6 ± 3 L/min

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
whole body
Vehicle:
air
Details on inhalation exposure:
The exposure chamber was a 2,500 L New York University-style stainless steel chamber with a pyramidal top and bottom. During exposure, animals were placed in individual stainless steel wire mesh cages, positioned in one tier in the chamber. The test substance was introduced using a jet mill which milled and fed the test material into an aerosol neutralizer. The aerosol passed through the neutralizer prior to entering the exposure chamber. The chamber concentration of test substance was controlled by regulating the speed at which the twin screw feed mechanism fed test substance into
the jet mill. Chamber airflow, temperature, and percent relative humidity was monitored and recorded approximately every 30 min. Mean airflow was determined to be 87.6±3.0 L/min. Mean temperature and relative humidity were 20.2±0.8⁰C and 20.9±0.7%, respectively. Oxygen level (21%) was determined once during the exposure using an electronic sensor. The equilibration period (T99) was determined to be 13.1 min.
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
2.3 mg/L
No. of animals per sex per dose:
5/sex
Control animals:
no
Details on study design:
Animals were observed hourly during exposure; however, the placement of cages allowed only limited observation of the animals. Mortality and moribundity were checked twice daily. Animals were observed for signs of toxicity immediately following exposure and once daily during the 14-d observation period after cessation of exposure. Body weights were determined on the exposure day (prior to exposure) and 2, 7, and 14 d following exposure. All animals were sacrificed 14 d after exposure and subjected to gross pathological examinations.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 2.3 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: 2.3 mg/L was the highest attainable concentration.
Mortality:
No
Clinical signs:
other: Immediately after exposure (Day 0), clear nasal discharge was noted in one male and perioral wetness was noted in two males and four females. On post-exposure Day 1, red/brown perinasal encrustation was noted in two males and three females. All animals ap
Body weight:
All animals lost weight from Day 0 to Day 2. By post-exposure Day 14, all animals exceeded their pre-exposure weights.
Gross pathology:
No gross abnormalities were observed at final necropsy.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Under the test conditions, the acute inhalation LC50 of MON 13900 was >2.3 mg/L in rats.
Executive summary:

A study was conducted to assess the acute inhalation toxicity of MON 13900 according to the EPA OPP 81-3 Guideline in compliance with GLP.

 

Five male and five female rats were exposed (whole body) for a single continuous 4 h period to an atmosphere of aerosolized test substance dust at the highest attainable mean analytical exposure concentration of 2.3 mg/L in air.

 

No deaths occurred, therefore, the LC50 was greater than 2.3 mg/L.