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Description of key information

Studies of acute oral, dermal and inhalation toxicity are available for sodium formate.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Referenceopen allclose all

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
secondary literature
Remarks:
Secondary source (ECB IUCLID 2000). The full report was not available for review.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
GLP compliance:
not specified
Test type:
standard acute method
Limit test:
no
Specific details on test material used for the study:
Assumingly Sodium Formate.
Species:
mouse
Strain:
C57BL
No. of animals per sex per dose:
12
Key result
Dose descriptor:
LD50
Effect level:
>= 3 700 - <= 4 700 mg/kg bw
Based on:
test mat.
Remarks on result:
other: Mice fed with a folic acid supplemented diet showed a slightly higher LD50 (4700 mg/kg) than mice fed a diet without folic acid supplements (LD50 3700 mg/kg)
Interpretation of results:
study cannot be used for classification
Conclusions:
Mice fed with a folic acid supplemented diet showed a slightly higher LD50 (4700 mg/kg) than mice fed a diet without folic acid supplements (LD50 3700 mg/kg).
Executive summary:

In a non-standard study, mice fed with a folic acid supplemented diet showed a slightly higher LD50 (4700 mg/kg bw) than mice fed a diet without folic acid supplements (LD50 3700 mg/kg bw).

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other:
Remarks:
Secondary source (ECB IUCLID 2000). The full report was not available for review.
Qualifier:
according to guideline
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
GLP compliance:
not specified
Specific details on test material used for the study:
Assumingly Sodium Formate.
Species:
rat
Dose descriptor:
LD50
Effect level:
> 3 000 mg/kg bw
Interpretation of results:
GHS criteria not met
Conclusions:
The acute oral LD50 of sodium formate in the rat is reported to be >3000 mg/kg bw.
Executive summary:

In a scondary source, the acute oral LD50 of sodium formate in the rat is reported to be >3000 mg/kg bw.

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other:
Remarks:
Summary with tables and figures of a pre-guideline study. Meets generally accepted scientific standards, well documented and acceptable for assessment. This report was submitted to the MAK commission of the Deutsche Forschungsgemeinschaft (DFG) assessing hazardous materials.
Principles of method if other than guideline:
Pre-guideline study. LD50 determination was presumably conducted similar to the method used in OECD guideline 401.
GLP compliance:
no
Test type:
standard acute method
Limit test:
no
Specific details on test material used for the study:
- Name of test material (as cited in study report): Na-Formiat
Species:
mouse
Strain:
not specified
Sex:
not specified
Details on test animals or test system and environmental conditions:
no data
Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
no data
Doses:
Applied doses not specified
No. of animals per sex per dose:
Total number of animals: 45
Control animals:
not specified
Sex:
not specified
Dose descriptor:
LD50
Effect level:
11 200 mg/kg bw
95% CL:
9 600 - 12 800

Table: oral LD50 of formic acid and its salts in the mouse:

 

 

Substance

LD50

(mg/kg bw)

LD50range

(mg/kg bw)

LD50,formate

(mg/kg bw)#

No of animals

Formic acid

1100

1000-1200

1076

55

Na-formate

11200

9600-12800

7410

45

K-formate

5500

5000-6000

2950

50

NH4-formate

2250

2050-2460

1610

50

Ca-formate

1920

1280 -2560

1330

45

 

# = calculated proportion of formate anion of the LD50dose.

Thus, the order of oral toxicity in mice was  formic acid  >  Ca, NH4, K salts  >  sodium formate.

 

Interpretation of results:
GHS criteria not met
Conclusions:
The oral LD50 of sodium formate was approx. 11200 mg/kg bw in mice. The oral toxicity of formic acid and its salts depended largely on the presence of H-ions, not on the presence of formate. Therefore formic acid was more toxic than the salts.

Executive summary:

The acute oral toxicity of formic acid and several of its salts was examined in male and female mice in a pre-guideline study. The aim was to establish LD50 values and elucidate the mode of action. Sodium formate was tested in a total of 45 mice. The oral LD50 was 11200 mg/kg bw (range: 9600-12800) in mice. The acute oral toxicity was therefore low (Malorny, 1969). This pre-guideline publication reviews the results of a variety of studies including metabolism and excretion, acute and repeated toxicity, and toxicity to reproduction. These results were used in the course of an early MAK-assessment. Though formal requirements for modern studies are not met, the published results are valuable for the assessment of formic acid and its salts. The study is considered to be valid (low reliability of 4 is assigned for formal reasons) and is used in a Weight of Evidence approach.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 000 mg/kg bw
Quality of whole database:
Three different reports are in the mouse and rat are available. Studies are of limited quality individually but note very low acute oral toxicity for sodium formate.

Acute toxicity: via inhalation route

Link to relevant study records
Reference
Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to 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).
Qualifier:
according to guideline
Guideline:
EPA OTS 798.1150 (Acute inhalation toxicity)
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes
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
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
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
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.

 

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

 

 

Interpretation of results:
GHS criteria not met
Conclusions:
The acute inhalation LC50 was found to be greater than 0.67 mg/L for a 4-hour inhalation exposure.
Executive summary:

In an acute inhalation toxicity test, five Sprague Dawley rats of either sex were exposed to an atmosphere containing ground sodium formate dust (4 hours 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 effects other than eye and nasal irritation. The acute inhalation LC50 is greater than 0.67 mg/L for a 4-hour inhalation exposure.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LC50
Value:
670 mg/m³
Quality of whole database:
A single guideline-compliant study is available for sodium formate

Acute toxicity: via dermal route

Link to relevant study records
Reference
Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
GLP compliance:
yes (incl. QA statement)
Test type:
standard acute method
Limit test:
yes
Specific details on test material used for the study:
- Name of test material (as cited in study report): sodium formate
- Substance type: salt
- Physical state: solid
- Analytical purity: 100%
- Lot/batch No.: 1292066
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: RCC Ltd, Füllinsdorf, Switzerland
- Age at study initiation: males 8-10 weeks, females 12-14 weeks
- Weight at study initiation: means: males 269 g; females 222 g
- Housing: single housing in Macrolon, type III cages
- Diet: complete diet from Kliba, Basel, Switzerland, ad libitum
- Water: ad libitum
- Acclimation period: 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70%
- Photoperiod (hrs dark / hrs light): 12/12
Type of coverage:
semiocclusive
Vehicle:
CMC (carboxymethyl cellulose)
Details on dermal exposure:
TEST SITE
- Area of exposure: approx. 40 cm²
- % coverage: 10
- Type of wrap if used: gauze and adhesive fleece (Fixomull stretch)


REMOVAL OF TEST SUBSTANCE
- Washing (if done): warm water
- Time after start of exposure: 24 hours


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mgsodium formate/kg bw; 2.02 mL/kg bw
- Concentration (if solution): 99%
- Constant volume or concentration used: yes
- For solids, paste formed: yes


VEHICLE
- Amount(s) applied (volume or weight with unit): 20 µL/kg bw
- Concentration (if solution): 1%
Duration of exposure:
24 hours
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
5
Control animals:
not required
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
-- Signs and symptoms: at least daily
-- Body weight: determined before application (day 0), and weekly thereafter

- Necropsy of survivors performed: yes
Statistics:
Probit analysis or a binominal test, depending on the results
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Mortality:
There was no mortality in male (0/5) or female rats (0/5).
Clinical signs:
There were no systemic clinical signs in male or female rats at any time.
Specifically, there were no local skin reactions in male or female rats at any time.

Body weight:
Mean male body weights on day 0, day 7, and day 14: 269/285/311 g
Mean female body weights on day 0, day 7, and day 14: 222/225/236 g
Gross pathology:
No findings in organs of males and females.
Interpretation of results:
GHS criteria not met
Conclusions:
The acute dermal LD50 of sodium formate was >2000 mg/kg bw in male and female Wistar rats.
Executive summary:

In an OECD TG 402 study Wistar rats (5/sex) were administered sodium formate on the fur-clipped dorsal skin at 2000 mg/kg bw under semi-occlusive conditions for 24 hours and observed for 14 days. The study was conducted under GLP conditions. No mortality or clinical signs of toxicity, skin reactions and no effects on body weights were seen, and no changes were seen in any organs during necropsy. The LD50 was > 2000 mg/kg bw (BASF AG, 2007). 

 

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 000 mg/kg bw
Quality of whole database:
A single guideline-compliant study is available for sodium formate

Additional information

Acute oral toxicity

There are several independent sources which, individually are not of high quality but can be used as weight of evidence to demonstrate that the acute oral toxicity in rodents is very low. First, the acute oral toxicity of formic acid and several of its salts was examined in male and female mice in a pre-guideline study. The aim was to establish LD50 values and elucidate the mode of action. Sodium formate was tested in a total of 45 mice. The oral LD50 was 11200 mg/kg bw in mice (Malorny, 1969). A second pre-guideline publication reviews the results of a variety of studies including metabolism and excretion, acute and repeated toxicity, and toxicity to reproduction. These results were used in the course of an early MAK-assessment. Though formal requirements for modern studies were not met, the published results are valuable for the assessment of formic acid and its salts. The study is considered to be valid (though a low reliability of 4 is assigned for formal reasons) and is used in a weight of evidence approach. Further, the LD50 in rats was reported to be >3000 mg/kg bw in two other studies (Smith, 1982; Huels, 1989).  Overall, it is concluded that the acute oral LD50 of sodium formate in rats and mice is >2000 mg/kg bw; sodium formate does not therefore require classification for acute oral toxicity according to CLP.

 

Acute inhalation toxicity

In an acute inhalation toxicity study, five Sprague Dawley rats of either sex were exposed to an atmosphere containing ground sodium formate dust (4 hours 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 effects other than eye and nasal irritation. The acute inhalation LC50 is >0.67 mg/L for a 4-hour inhalation exposure. Sodium formate does not therefore require classification for acute inhalation toxicity according to CLP.

Acute dermal toxicity

In an OECD TG 402 study Wistar rats (5/sex) were administered sodium formate on the fur-clipped dorsal skin at 2000 mg/kg bw under semi-occlusive conditions for 24 hours and observed for 14 days.  The study was conducted under GLP conditions. No mortality or clinical signs of toxicity, skin reactions and no effects on body weights were seen, and no changes were seen in any organs during necropsy. The LD50 was > 2000 mg/kg bw (BASF AG, 2007). Sodium formate does not therefore require classification for acute dermal toxicity according to CLP.

Justification for classification or non-classification

Studies of acute oral, dermal and inhalation toxicity are available for sodium formate and demonstrate low toxcity by all routes. Based on the results of the available studies, sodium formate does not require classification for acute toxicity according to the CLP Regulation.