Potassium hydrogencarbonate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993-10-14 to 1993-10-28

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: US EPA Pesticide Assessment Guidelines, Subdivision F, Hazard Evaluation: Human and Domestic Animals, November 1984, Acute Exposure, Inhalation

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Potassium hydrogencarbonate

EC Number:

206-059-0

EC Name:

Potassium hydrogencarbonate

Cas Number:

298-14-6

Molecular formula:

CH2O3.K

IUPAC Name:

potassium hydrogen carbonate

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hilltop Lab Animals, Scottdale, PA, USA
- Age at study initiation: no data in study summary
- Weight at study initiation: 219 - 256 g
- Fasting period before no data in study summary
- Housing: no data in study summary
- Diet (e.g. ad libitum): no data in study summary
- Water (e.g. ad libitum): no data in study summary
- Acclimation period: no data in study summary


ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data in study summary
- Humidity (%): no data in study summary
- Air changes (per hr): no data in study summary
- Photoperiod (hrs dark / hrs light): no data in study summary

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

not specified

Details on inhalation exposure:

Prior to aerosolization, the test substance was ground for 24 hours in a ball mill.
Chamber concentration and the particle size distribution of the aerosolized test substance were determined periodically during the exposure period.

The gravimetric chamber concentration was 4 .88 ± 0.60 mg/L with approximately 1 % of the particles below 1 µm and 25 % below 3 µm. The mass median aerodynamic diameter was approximately 4.7 µm.

Particle size distribution was measured by the Andersen Cascade Impactor.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

gravimetric

Duration of exposure:

4.5 h

Concentrations:

4 .88 ± 0.60 mg/L gravimetric chamber concentration

No. of animals per sex per dose:

5 animals per sex/dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: no data in study summary
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 4.88 mg/L air (analytical)

Exp. duration:

4.5 h

Remarks on result:

other: no animal died; 4 .88 ± 0.60 mg/L

Mortality:

No mortalities occurred as a result of exposure.

Clinical signs:

other: In-chamber animal observations were limited due to the accumulation of test substance on the walls of the exposure chamber. During the first hour of exposure, decreased activity, ocular discharge and hunched posture were noted. Upon chamber removal, simil

Body weight:

All rats gained weight over the 14-day observation period.

Gross pathology:

Gross necropsy findings at terminal sacrifice were generally unremarkable. Apart from red lung discoloration consistent with euthanasia by CO2 inhalation, all tissues and organs appeared normal.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

On the basis of the results obtained after an inhalation exposure of 4.5 h, the LC50 of the test article "Potassium Bicarbonate" was determined to be > 4.88 ± 0.60 mg/L.

Executive summary:

In an acute inhalation toxicity study performed according to the US EPA Pesticide Assessment Guidelines, Subdivision F, Hazard Evaluation: Human and Domestic Animals, November 1984, Acute Exposure, Inhalation, which is similar to OECD Guideline 403 (Acute Inhalation Toxicity), 5 male and 5 female Sprague-Dawley rats were exposed by inhalation route to aerosolized test article “Potassium Bicarbonate” for 4.5 hours. Test substance was aerosolized after being ground in a ball mill for 24 hours. The gravimetric chamber concentration was 4.88 ± 0.60 mg/L with approximately 1 % of the particles below 1 µm and 25 % below 3 µm. The mass median aerodynamic diameter (MMAD) was approximately 4.7 µm. Animals were observed for 14 days.

LC₅₀ Combined:  > 4.88 ± 0.60 mg/L air (analytical)

 

No animal died in this study. During the first hour of exposure, decreased activity, ocular discharge and hunched posture were noted. Upon chamber removal, similar conditions as well as facial staining and/or nasal discharge were evident. All animals recovered from these clinical signs within 24 hours. All rats gained weight over the 14-day observation period. There were no substance related gross necropsy findings at terminal sacrifice.

In this limit test the determined LC₅₀ is > 4.88 ± 0.60 mg/L air (analytical). As no animal died, it is considered to be appropriate not to classify the substance for acute inhalation toxicity according to CLP, EU GHS (Regulation (EC) No 1272/2008).

EU GHS limit values for acute inhalation toxicity are 1.0 < category 4 ≥ 5.0 mg/L for dust/mist. Furthermore the exposure time was slight increased (4.5 h) when compared with the EU GHS requirement of 4 hours inhalation exposure.