Calcium nitrite

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Not specified

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

OECD SIDS (2005) describe as "critical study for SIDS endpoint", but with a reliability score of 4 ("not assignable") as it could not be evaluated by OECD assessors. Study evidently to GLP.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1985

Report date:

1985

Reference 2

Reference Type:

review article or handbook

Title:

SIDS Initial Assessment Report (SIAR) for SIAM 20. Sodium nitrite, CAS No: 7632-00-0.

Author:

OECD

Year:

2005

Bibliographic source:

Organization for Economic Co-operation and Development. Screening Information Dataset.

Report date:

2005

Reference 3

Reference Type:

review article or handbook

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Principles of method if other than guideline:

It is not apparent from the citing OECD SIDS (2005) review if an official test guideline was followed.

Groups of Wistar rats (10/sex) were exposed (nose-only) for 4 hours to sodium nitrite aerosols, generated from solutions in deionised water, at target concentrations of 10 or 100 mg/m3. Aerosols dried rapidly so animals were exposed to dry particulate test material. Mass mean aerodynamic diameter was 1.7 and 2.0 μm for the low and high groups respectively. Methaemoglobin levels were measured after exposure and the remaining animals maintained for 14 days, and then subject to a full post-mortem examination.

GLP compliance:

yes

Test type:

traditional method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Sodium nitrite

EC Number:

231-555-9

EC Name:

Sodium nitrite

Cas Number:

7632-00-0

Molecular formula:

HNO2.Na

IUPAC Name:

sodium nitrite

Test material form:

aerosol dispenser: not specified

Details on test material:

[No further details provided in citing OECD and ECB reviews]

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: not specified in citing OECD and ECB reviews
- Females (if applicable) nulliparous and non-pregnant: not specified in citing OECD and ECB reviews
- Age at study initiation: not specified in citing OECD and ECB reviews
- Weight at study initiation: not specified in citing OECD and ECB reviews
- Fasting period before study: not specified in citing OECD and ECB reviews
- Housing: not specified in citing OECD and ECB reviews
- Diet (e.g. ad libitum): not specified in citing OECD and ECB reviews
- Water (e.g. ad libitum): not specified in citing OECD and ECB reviews
- Acclimation period: not specified in citing OECD and ECB reviews

ENVIRONMENTAL CONDITIONS
- Temperature (°C): not specified in citing OECD and ECB reviews
- Humidity (%): approximately 60%
- Air changes (per hr): not specified in citing OECD and ECB reviews
- Photoperiod (hrs dark / hrs light): not specified in citing OECD and ECB reviews

IN-LIFE DATES: not specified in citing OECD and ECB reviews

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

not specified

Mass median aerodynamic diameter (MMAD):

ca. 1.7 - ca. 2 µm

Remark on MMAD/GSD:

Mass mean aerodynamic diameter was 1.7 and 2.0 μm for the low and high groups respectively. GSD was not specified in citing OECD and ECB reviews.

Details on inhalation exposure:

[No further details provided in citing OECD and ECB reviews]

Analytical verification of test atmosphere concentrations:

yes

Remarks:

High dose achieved 95.1 mg/m3

Duration of exposure:

4 h

Concentrations:

10 or 100 mg/m3 [high dose evidently achieved 95.1 mg/m3]

No. of animals per sex per dose:

10

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: not specified in citing OECD and ECB reviews
- Necropsy of survivors performed: yes
- Other examinations performed: methaemoglobin levels following exposure

Statistics:

[Not specified in citing OECD and ECB reviews]

Results and discussion

Preliminary study:

[Not specified in citing OECD and ECB reviews]

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 100 mg/m³ air (nominal)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortaility observed up to 14 days post exposure.

Clinical signs:

other: None specified [extent of assessment unclear from citing OECD and ECB reviews]

Body weight:

[Unclear if body weights assessed from citing OECD and ECB reviews]

Gross pathology:

None reported

Other findings:

"Methaemoglobin was significantly increased above concurrent control values only in females exposed to 10 mg/m3. However, the increase was judged to be not haematologically
significant as the value was within the range seen for control animals of this age. Further there was no significant increase in males. There were no toxicologically significant effects on animals maintained for 14 days post-exposure".

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Conclusions:

According to OECD (2005) and ECB (2000), briefly describing the findings of an unpublished GLP acute inhalation study, there was no mortality or other toxicologically significant adverse effects in rats (10/sex/group) during a14-day observation period following a 4-hr exposure to up to 100 mg/m3 of sodium nitrite. As such, a 4-hr LC50 of >100 mg/m3 can be concluded for sodium nitrite.

Executive summary:

According to OECD (2005) and ECB (2000), briefly describing the findings of an unpublished GLP acute inhalationstudy, groups of 10 male and 10 female Wistar rats were exposed nose only for 4 hours to sodium nitrite aerosols, generated from solutions in deionised water, at target concentrations of 0, 10 or 100 mg/m3 (and achieving 95.1 mg/m3). Aerosols dried rapidly so animals were exposed to dry particulate test material. Mass mean aerodynamic diameter was 1.7 and 2.0 μm for the low and high groups respectively. Methaemoglobin levels were measured following exposure. The remaining animals were maintained for 14 days, and then subject to a “full post-mortem examination”.

No mortality or other toxicologically significant adverse effects were reported. As such, a 4-hr LC50 of >100 mg/m3 can be concluded for sodium nitrite.