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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Only one concentration level tested. Large discrepancy between nominal and measured concentration (0.67 mg/L vs. 10 mg/L target concentration).

Data source

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

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
EPA OTS 798.1150 (Acute inhalation toxicity)
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium formate
EC Number:
205-488-0
EC Name:
Sodium formate
Cas Number:
141-53-7
Molecular formula:
CHO2Na
IUPAC Name:
sodium formate
Details on test material:
- Name of test material (as cited in study report): C-1261 (Sodium Formate)
- Substance type: white powder
- Physical state: solid
- Analytical purity: 99% active ingredient
Specific details on test material used for the study:
- Name of test material (as cited in study report): C-1261 (Sodium Formate)
- Substance type: white powder
- Physical state: solid
- Analytical purity: 99% active ingredient

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Age at study initiation: males 9 weeks, females 10 weeks
- Weight at study initiation: mean weights: males 337 g; females 235 g
- Fasting period before study: no data
- Housing: individually
- Diet: ad libitum; standard laboratory diet
- Water: ad libitum
- Acclimation period: 15 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): slightly higher than the desired range of 20-24°C
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: day 1 To: day 15

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
whole body
Vehicle:
other: unchanged (no vehicle)
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
0.67 mg/l
No. of animals per sex per dose:
5
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations: daily; weighing: on days days 1, 2, 3, 5, 8, and 15
- Necropsy of survivors performed: yes
Statistics:
not required

Results and discussion

Effect levelsopen allclose all
Sex:
male/female
Dose descriptor:
LC0
Effect level:
> 0.67 mg/L air
Exp. duration:
4 h
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 0.67 mg/L air
Exp. duration:
4 h
Mortality:
There were no deaths during the exposure or the 14-day observation period. 
Clinical signs:
other: Adverse clinical sighs were minimal and consisted of decreased activity and eyes partly or fully closed during the exposure, and lacrimation and nasal discharge but generally fully recovered within a week. 
Body weight:
There was a slight and transient reduction in body weight gain following the exposure but all animals continued to gain weight a few days after the exposure period (cf. section: Any other information on results)
Gross pathology:
No findings that could be related to treatment.
Other findings:
Atmosphere
The chamber temperature was 25 degrees and the relative humidity ranges for 17% to 6% with the lower values in the latter part of the study (considered as a result of the dessicant activity of fine particles of sodium formate). Chamber concentration of test material was measured at nine intervals during the study and ranged from 0.5 to 0.86 mg/L.

Any other information on results incl. tables

 

Mean terminal body weights (grams); 4-hour exposure, 0.67 mg/L

 

Day

Females

Males

1

235

337

2

230

333

5

236

344

8

244

365

15

255

414

 

 

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The acute inhalation LC50 is greater than 0.67 mg/L. This was the highest practicable concentration whch could be acheived. No mortality was seen at this dose.
Executive summary:

In an acute inhalation toxicity test, 5 Sprague Dawley rats of either sex were exposed to an atmosphere containing ground sodium formate dust (4hours whole body exposure). The study was conducted according to the US EPA guideline EPA OTS 798.1150 (similar to OECD guideline 403) and under GLP conditions. The target concentration was 10 mg/L, the observation period 14 days.

 

The mean gravimetric particle concentration was 0.67 mg/L under the conditions of this study. The average mass median aerodynamic diameter was 5.4 µm with an average geometric standard deviation of 2.4 µm. There were no mortalities. Signs of treatment were minimal and included nasal discharge and lacrimation after treatment with recovery within one week, and a transient reduction of body weight gain. No treatment-related changes were seen at the terminal necropsy (Biodynamics, 1990).

 

Overall, exposure of rats to the highest practical aerosol concentration of test material, with a large portion in the respirable range, was not

associated with adverse effect other than eye and nasal irritation. The acute inhalation LC50is greater than 0.67 mg/L for a 4-hour inhalation exposure. The study provides useful information, though inhalation is not considered to represent a relevant route of exposure for a solid like sodium formate.