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Toxicological information

Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Unreliable testing facility: study protocol equivalent or similar to OECD Guideline 403 (TS concentration in testing atmosphere <5 mg/l, no MMAD / GSD, whole body exposure, no details on analytical verification of test atmosphere concentration, body weight determined only twice [start and end]; TS purity not specified; no GLP)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1972
Report Date:
1972

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Version / remarks:
Dust
Deviations:
yes
Remarks:
TS concentration in testing atmosphere <5 mg/l, no MMAD / GSD, whole body exposure, no details on analytical verification of test atmosphere concentration, body weight determined only twice [start and end]; TS purity not specified
GLP compliance:
no
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Physical state: red powder
- Lot/batch No.: 2415-72

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: ARS/Sprague-Dawley, Madison, Wisconsin
- Age at study initiation: no data (young albino rats)
- Weight at study initiation: 205
- Housing: housed in stock cages
- Diet (e.g. ad libitum): standard laboratory diet (Purina Rat Chow, Ralston Purina Company, St. Louis, Missouri); ad libitum, except during inhalation exposure
- Water (e.g. ad libitum): drinking water; ad libitum , except during inhalation exposure
- Acclimation period: at leat 5 days

ENVIRONMENTAL CONDITIONS
No data

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
whole body
Vehicle:
clean air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: test animals were exposed in a specially constructed Plexiglas inhalation chamber. The chamber was designed so that the animals could be introduced to the test atmosphere after the maximum dust concentration was established.
- Exposure chamber volume: 70 liters
- Method of holding animals in test chamber: not further specified; each animal was caged separately during exposure to minimize filtration of inspired air by animal fur.
- Source and rate of air: air flow rate through the system was 4.1 L/min at 29.92 inches Hg and 25°C (measured with a rotameter connected upstream of the dust feeder). The rotameter was calibrated with a wet-test meter after the exposure was completed.
- System of generating particulates/aerosols: dust was suspended with a specially designed dust feeder capable of producing high concentrations over a long period of time. The test material powder was passed through a high-velocity stream of clean dry air (-40°C dewpoint). The resulting air and dust mixture was then introduced into the exposure chamber at the top center, dispersed by a baffle plate and exhausted at the bottom of the chamber.
- Method of particle size determination: a sample of airborne dust was collected from the test atmosphere for the purpose of conducting a microscopic determination of particle size distribution. Particles were counted with respect to three size ranges, viz. 5 µm or smaller (considered to be respirable), 6-25 µm and >25 µm. The smallest particle which can be detected by the light-field technique employed is approximately µm. The largest particle observed was also recorded.
- Treatment of exhaust air: no data
- Temperature, humidity, pressure in air chamber: the temperature of the test atmosphere was 22.5°C and the pressure was 30.50 inches Hg.

TEST ATMOSPHERE
- Brief description of analytical method used: the concentration of test material dust present in the exposure chamber was determined by sampling the test atmosphere in the breathing zone of the animals being exposed. The total weight of dust collected on a glass fiber filter was divided by the total volume of air drawn through the filter during the sampling period. Air flow rate for sampling was regulated by a calibrated limiting orifice. The average concentration of airborne dust, obtained by repeated air sampling, was 2200 mg/m3 air at 25°C and 29.92 inches Hg.
- Samples taken from breathing zone: yes

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: Table 1
Analytical verification of test atmosphere concentrations:
not specified
Remarks:
not specified
Duration of exposure:
4 h
Concentrations:
2200 mg/m3
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: initial and final body weights and reactions were recorded; the exposure was designed to run for a 4-hour period, during which time observations were made with respect to incidence of mortality and reactions displayed. At the end of the exposure period, the rats were returned to their stock cages and observed for the following 14 days.
- Necropsy of survivors performed: yes, gross pathologic examinations were scheduled to be conducted upon all animals which might succumb during the test period and upon those sacrificed at the end of the 14-day observation period.
Statistics:
In the event of significant mortality following the initial exposure, arrangements were made to conduct additional experiments at lower dust concentrations in order to acquire data sufficient to calculate the acute dust inhalation median lethal concentration (LC50) of the test material employing the method of Litchfield and Wilcoxon.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 2 200 mg/m³ air (nominal)
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: No deaths were noted during the four-hour exposure period or 14-day observation period which followed
Mortality:
No deaths were noted during the four-hour exposure period or 14-day observation period which followed.
Clinical signs:
other: No abnormal behavioral reactions were noted during the four-hour exposure period or 14-day observation period which followed.
Body weight:
Some animals lost weight and the average body weight gain was slightly lower than historical control data (Table 1).
Gross pathology:
Necropsy, performed on all animals at the end of the two-week observation period, revealed slight to moderate diffuse focal red discoloration of the lungs in six rats. There were no other gross pathologic alterations in any of the other tissues and organs examined.

Any other information on results incl. tables

Table 2: Body weight data

Animal number and sex

Individual and mean body weights and body weight gain (g)

Body weights (g) after

14-day body weight gain

0 day

14 days

1-Male

241

234

-7

2-Male

221

249

28

3-Male

236

262

26

4-Male

228

223

-5

5-Male

223

231

8

Mean

230

240

10

1-Female

187

210

23

2-Female

185

174

-11

3-Female

175

170

-5

4-Female

179

174

-5

5-Female

175

195

20

Mean

180

185

4

Historical control data: the average 14-day body weight gain for a group of rats equally sexed and weighing 175 to 225 grams is approximately 25 to 35 grams.

 

Applicant's summary and conclusion