Calcium diformate

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: Comparable to guideline study with restrictions. Restriction: 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

Test material information

Constituent 1

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

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 levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LC0

Effect level:

> 0.67 mg/L air

Exp. duration:

4 h

Effect levels 2

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

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.