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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
Study period:
January 1991 - February 1991
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: study performed according to guideline and under GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EPA OPP 81-3 (Acute inhalation toxicity)
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Principles of method if other than guideline:
Two limit tests are performed:
The target gravimetric chamber concentration (5 mg/mL which is also required by OECD 403) and particle size distribution (25% < 1 micron) could not be reached simultaneously. Therefore two experiments were performed in which one of both parameters was optimal.
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Sodium Chlorate Crystal (Ercocide C)
- Physical state: white flaked solid
- Analytical purity: 101.1% Sodium Chlorate Crystal
- Impurities (identity and concentrations): Chromium concentration = 2.1 ppm as Cr6
- Composition of test material, percentage of components: 101.1% Sodium Chlorate Crystal (Ercocide C)
- Purity test date: October 3, 1990 - October 11, 1990
- Lot/batch No.: Batch #DL-1 and further identified with PSL Code Number E01023-4
- Expiration date of the lot/batch: 9-1-91
- Stability under test conditions: Stable at ambient temperature
- Storage condition of test material: Cool and dry storage
- Other: pH 5.5; test substance received on October 23, 1990; 101.1% Sodium Chlorate Crytsral (Ercocide C) received from
the Sodium Chlorate Task Force.

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Hilltop Lab Animals, Scottdale, PA
- Age at study initiation: Young adult
- Weight at study initiation: weighing 216 - 249 g
- Fasting period before study: no info
- Housing: individually in suspended stainless steel caging with mesh floors
- Diet (e.g. ad libitum): Pelleted Purina Rat Chow, ad lib
- Water (e.g. ad libitum): Tap water supplied by automatic water system, ad lib
- Acclimation period: 7 or 12 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): Limit test 1: 22 - 23; Limit test 2: 21 - 24
- Humidity (%): no info
- Air changes (per hr): no info
- Photoperiod (hrs dark / hrs light): no info


IN-LIFE DATES: From: January 30, 1991 To: February 25, 1991

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
whole body
Vehicle:
other:
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Rectangular perspex gravimetric chamber with a volume of 100 liters operated under slight negative pressure.
- Exposure chamber volume: 100 L
- Method of holding animals in test chamber: individually in stainless steel mesh cages within the inhalation chamber.
- Source and rate of air: breathing grade air from a compressed gas cylinder and additional "diluent" air from a filtered conditioned ambient source. Air flows were 26.1 – 28.2 lpm (limit test 1) and 34.6 – 38.8 lpm (limit test 2).
- Method of conditioning air: breathing grade air from a compressed gas cylinder and additional "diluent" air from a filtered conditioned ambient source.
- System of generating particulates/aerosols: 1/4 inch JCO atomizer (Spraying Systems Inc.) #2050 fluid cap and #73160 air cap. The test material was metered to the atomization nozzle through size 14 tygon tubing using a Master Flex Pump (Model 7520-35). In an attempt to affect the particle size distribution during Limit Test #1 and most of its associated trials, a circular tin disk (diameter 9.5 cm) was placed inside the exposure chamber 53 to 106 mm in front of the nebulizer during aerosol generation. Since this process tended to drastically lower attainable chamber concentration, it was not used for Limit Test #2.
- Method of particle size determination: An eight-stage Andersen cascade impactor was used to assess the particle size distribution of the test atmosphere. The filter paper collection stages were weighed before and at least 10 minutes after each sampling to determine the mass collected at each stage on a dry weight basis. The MMAD and GSD were determined graphically using two-cycle logarithmic probit axes.
- Treatment of exhaust air: no info
- Temperature, humidity, pressure in air chamber:
Chamber temperature range (°C): 22-23 (limit test 1) and 19-20 (limit test 2)
Rel. Humidity (% RH): 32.1-39.0 (limit test 1) and 27.2-32.5 (limit test 2)
Chamber under slight negative pressure.
T90 (min): 6-8
T99 (min): 13-17


TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetric samples were withdrawn on 5 or 6 occasions from the breathing zone of the animals. Samples were collected using membrane filters in filter holders attached by 1/4 inch tygon tubing to a sampling pump. Filter papers were weighed before and at least 10 minutes after each sampling to determine the mass collected on a dry weight basis. On several occasions filters were re-weighed after 30 minutes to verify that complete drying had occurred. The collections were carried out for 1 minute at air flows of 4 lpm.
- Samples taken from breathing zone: yes


VEHICLE
- Composition of vehicle (if applicable): distilled water
- Concentration of test material in vehicle (if applicable): test material was aerosolized as a 33.3% w/w solution in distilled water
- Justification of choice of vehicle: no info


TEST ATMOSPHERE (if not tabulated)
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.):
Limit test 1: sample 1, MMAD = 2.1 µm and GSD = 1.9; sample 2, MMAD = 2.2 and GSD = 2.0
Limit test 2: sample 1, MMAD = 3.0 µm and GSD = 1.7; sample 2, MMAD = 3.0 and GSD = 1.8
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4.5 h
Concentrations:
limit test 1: 1.42 ± 0.38 mg/l (nominal concentration = 637.5 mg/L, 33.3% w/w solution)
limit test 2: 5.59 ± 1.64 mg/l (nominal concentration = 229.9 mg/L, 33.3% w/w solution)
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Animals were observed before exposure commencement, every 15 minutes during the first exposure hour, and every 30 minutes thereafter through exposure termination. On removal from the chamber the animals were individually examined. Bodyweights were recorded prior to exposure and on days 1, 2, 4, 7, 10 and 14.
- Necropsy of survivors performed: yes, All survivors to termination were euthanized by diethyl ether inhalation and subjected to necropsy examination. The lungs of all animals were removed and placed in buffered formalin.
- Other examinations performed: clinical signs, body weight, histopathology
Statistics:
Not required.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5.59 mg/L air
Exp. duration:
4.5 h
Mortality:
- Limit test 1: no mortality
- Limit test 2: no mortality
Clinical signs:
other:
Body weight:
- Limit test 1: All animals gained weight over the 14-day observation period.
- Limit test 2: All animals gained weight overall.
Gross pathology:
- Limit test 1: Red discoloration of the lungs in most animals (4 males and 2 females). Small cysts (1 female) or uneven texture (1 female and 1 male) was evident on the surface of the lungs.
- Limit test 2: Red discoloration of the lungs in all animals. The jejunum of 2 females from was red in colour.

Applicant's summary and conclusion

Interpretation of results:
Category 5 based on GHS criteria
Remarks:
Migrated information
Conclusions:
The acute (4.5 h) inhalation LC50 of aerosolized Sodium Chlorate Crystal was determined to be greater than 5.59 mg/L in males and females. Because higher concentrations than 5.59 mg/L had not been tested and effects at those concentrations are unknown the test material was classified in Category 5 according to OECD-GHS.
Executive summary:

Sodium Chlorate was evaluated for its acute inhalation toxicity potential in albino rats. The study was performed in accordance with EPA Pesticide Assessment Guidelines, Subdivision F, Hazard Evaluation: Human and Domestic Animals, November 1984, Acute Exposure, acute Inhalation Toxicity. Similar to OECD Guideline 403 (Acute Inhalation Toxicity). The study was designed and performed according to Good Laboratory Practice Standards.

The target gravimetric chamber concentration (5 mg/mL, which is also required by OECD 403) and particle size distribution (25% 1 micron) could not be reached simultaneously. Therefore two limit tests were performed in which one of both parameters was optimal. Five males and five females were assigned to each study and they were exposed for 4 ½ hours to an aerosol (test atmosphere generated from a 33.3% w/w solution in distilled water) at a level of 1.42 mg/L (limit test 1) and 5.59 mg/L (limit test 2). There was no mortality during both studies. Clinical signs of toxicity included facial staining, reduced movement, test material-stained fur and closed eyes and in limit test 2 also irregular respiration and hunched posture, which were no longer evident on Day 1 (limit test 1) or Day 2 (limit test 2). Observations were up to 14 days and all animals gained weight overall. The gross necropsy showed red discoloration of the lungs in most animals.

The acute (4.5 h) inhalation LC50 of aerosolized Sodium Chlorate Crystal was determined to be greater than 5.59 mg/L in males and females. Because higher concentrations than 5.59 mg/L had not been tested and effects at higher concentrations are unknown the test material was classified in Category 5 according to OECD-GHS.