Sodium tetrahydroborate

Acute Toxicity: inhalation

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: Basic data given

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1974

Report date:

1974

Materials and methods

Test guideline

Qualifier:

no guideline available

Guideline:

other: Continuous dynamic exposure method

Principles of method if other than guideline:

A semi-portable chamber was used for exposure. An exhaust fan was utilized to provide an adjustable air flow. Test material was administered into the incoming airstream just before it entered the circular hood of the chamber.

GLP compliance:

no

Test type:

other: Continuous dynamic exposure method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Sodium tetrahydroborate

EC Number:

241-004-4

EC Name:

Sodium tetrahydroborate

Cas Number:

16940-66-2

Molecular formula:

BH4.Na

IUPAC Name:

Sodium tetrahydridoborate(1–)

Details on test material:

- Name of test material (as cited in study report): Sodium borohydride
- Physical state: powder
- Lot/batch No.: 3-97

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 200 g
- Housing: animals were confined individually in cages constructed entirely of 3/8 inch screen to be placed into the chamber; Following exposure, five of the exposed animals and five of the control animals were placed in screen bottom cages.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: minimum of four weeks

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: a semi-portable exposure chamber similar to those developed by the Public Health Service in the Taft Laboratories at Cincinnati.
- Exposure chamber volume: not reported
- Method of holding animals in test chamber: confined individually in cages constructed entirely of 3/8 inch screen and placed in a central location in the chamber
- Source and rate of air: an exhaust fan was utilized to provide an adjustable air flow through the chamber. Test material was administered into the incoming airstream just before it entered the circular hood of the chamber. Air flow was maintained at 586 liters/air.
- Method of conditioning air: not reported
- System of generating particulates/aerosols: The material was sprayed into the air stream using a Wright Dust Feeder.
- Method of particle size determination: not reported
- Treatment of exhaust air: no data
- Temperature, humidity, pressure in air chamber: not reported


TEST ATMOSPHERE
Air flow was calculated from the pressure drop across a measured inlet orifice in a steel plate. Because of the quantity of material administered, a certain amount came directly in contact with the inlet pipe and circular hood of the chamber. This material was collected, measued and the amount subtracted from the total material administered when calculating the actual exposure level. The final exposure was calculated in mg per liter by subtracting the amount recovered from upper chamber from the total amount sprayed into the chamber and dividing this difference by the total cubic feet of air circulated through the chamber.


VEHICLE
Not applicable

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

1 h

Concentrations:

5.18 mg/L air

No. of animals per sex per dose:

10

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days; 5 exposed and 5 control animals were sacrificed 30 minutes after completion of the exposure period. The remaining 5 exposed and 5 control animals were observed for 14 days.
- Frequency of observations and weighing: gross observation at necropsy; weighing not reported.
- Necropsy of survivors performed: yes
- Other examinations performed: histopathological: lungs and trachea removed and preserved in fixative. The lungs were inflated with fixative before removal by clamping off the trachea with a hemostat and injecting the fixative into the trachea between the hemostat and the lungs.

Statistics:

Not reported

Results and discussion

Effect levels

Sex:

male

Dose descriptor:

LC50

Effect level:

> 5.18 mg/L air

Exp. duration:

1 h

Mortality:

No deaths

Clinical signs:

other: Not reported

Body weight:

Not reported

Gross pathology:

No effects

Other findings:

- Histopathology: sections of lung and trachea show no tissue pathology. Alterations seen occur in both control and test animals and not considered to be treatment related.

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute inhalation LC50 is greater than 5.18 mg/L at 1 hour (converted to > 1.3 mg/l at 4 hours).