Dimethyl ether-boron trifluoride

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure in accordance with normal standard methods.

Data source

Reference

Reference Type:

publication

Title:

Inhalation toxicity Studies with Boron Trifluoride

Author:

Rusch GM et al.

Year:

1986

Bibliographic source:

Toxicol. and Appl. Pharmacol., 83, 67-78

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

not specified

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

13319-75-0

EC Number:

603-716-7

Cas Number:

13319-75-0

IUPAC Name:

13319-75-0

Details on test material:

- Name of the test substance: Boron trifluoride dihydrate
- Source: Allied Corporation
- Batch number: no data
- Purity: The substance was tested in a dihydrate form which contained 63.87% of BF3.

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Labs (Portage, Mich.)
- Age at study initiation: approximately 7 weeks old
- Weight at study initiation: no data
- Fasting period before study: no
- Housing: individually in suspended stainless-steel mesh cages
- Diet (e.g. ad libitum): ad libitum Purin Rat Chow 5001
- Water (e.g. ad libitum): ad libitum
- Acclimation period: for a minimum of 2 weeks

ENVIRONMENTAL CONDITIONS: no data

Administration / exposure

Route of administration:

inhalation

Type of inhalation exposure:

whole body

Vehicle:

other: air

Details on inhalation exposure:

Exposure Chamber Designs and Operation
The acute exposure was conducted in 225-liter stainless-steel and glass exposure chambers, operated under negative pressure with filtered, conditioned air.
The total flow rate during the acute study was approximately 50 liters/min, providing a t99 equilibration time of 21 min.

Test Atmosphere Generation Procedures
Test atmospheres in the acute study were generated with a Solo-Sphere nebulizer (McGraw Respiratory Therapy, Irvine, CA.) operated with compressed, breathing-grade air. Exposure concentrations were controlled by regulating the airflow through the nebulizer, and thus the rate of aerosol generation.

Analysis of Chamber Concentrations
Nominal aerosol concentrations were determined daily by measuring the amount of test material consumed during the exposure and dividing this by the total airflow through the chamber. At hourly intervals, actual air concentration measurements were made by trapping aerosol samples of known volume in I5-ml impingers, using a flow-Gmiting orifice (Millipore XX50000014) with a pump (Gast DOA-122) and dry test meter (Singer DTM-115-3) for volume measurement. The aerosol was then dissolved in distilled water and analyzed for BF3 content by an ion-selective electrode technique. Sample volumes were varied to permit collection of roughly equal quantities of BF3.
Particle size measurements were made with an Anderson I ACFM particle sizing sampler (Anderson 2000, Inc., Atlanta, Ga.). Measurements were performed hourly during the acute exposures; three times/week during the subacute exposures; and twice each week during the subchronic exposures. The material collected on each stage was determined gravimetrically.
Mass median aerodynamic diameter: 1.8 µm

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

1.01, 1.22, 1.32 and 1.54 mg/l

No. of animals per sex per dose:

5 males + 5 females

Control animals:

no

Details on study design:

EXAMINATIONS: 
Duration of observation: 14 days
- Clinical signs: examined just before exposure, at 15-minute intervals  during the first hour then hourly for the remaining of exposure and daily until the completion of the study.
- Mortality: idem
- Body weight: measured on days 1, 2, 4, 7 and 14
- Necropsy:
. macroscopic examination of the main organs: yes
. microscopic examination: no

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

1 210 mg/m³ air

Exp. duration:

4 h

Mortality:

Deaths occurred in all exposure groups: nine (out of 10) at 1.54 mg/l,  eight at 1.32 mg/l, two at 1.22 mg/l, and three at 1.01 mg/l, ranging  from the day of the exposure to 6 days post-exposure. 

Clinical signs:

other: Clinical signs elicited by the exposures included dry and moist rales,  gasping, excessive oral and nasal discharge, and lacrimation, indicative  of respiratory distress and irritation. Recovery was apparent for the  rats surviving beyond 6 days post-expo

Body weight:

A body weight decrease was recorded.

Gross pathology:

A decrease in liver and kidney decrease was noted.

Applicant's summary and conclusion

Conclusions:

An LC50 of 1.21 mg/l or 1210 mg/m3 was calculated for a 4-hr exposure to boron trifluoride. The animals exhibited clinical signs of oral and nasal discharge, gasping, lacrimation, indicative of irritation and respiratory distress. Recovery was apparent for the rats surviving beyond 6 days post-exposure.