Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1987
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented with GLP compliance, but data concerning macroscopic or histopathological examinations not reported

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1987
Report date:
1987

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
yes
Remarks:
The ALC (defined as the lowest atmospheric concentration tested that caused the death of 1 or more rats within 14 days of exposure) was calculated in this study. The 4-hours LC50 was re-calculated at a later stage
GLP compliance:
yes
Test type:
standard acute method
Limit test:
no

Test material

Constituent 1
Reference substance name:
10486-00-7
EC Number:
600-611-8
Cas Number:
10486-00-7
IUPAC Name:
10486-00-7
Details on test material:
-Name of test material (as cited in study report): Perboric acid, sodium salt, tetrahydrate
-Physical state: White powder
-Purity: 98.6 %
-Lot/batch No.: 16,703 (Haskell Lab.)
-Other Code: 5# Fine SPBT D50 of 13.3 microns
-Stability under test conditions: Test material was assumed to be stable throughout the exposure phase of the test

Test animals

Species:
rat
Strain:
other: Crl:CD BR
Sex:
male
Details on test animals or test system and environmental conditions:
TEST ANIMALS
-Source: Charles River Breeding Lab., Kingston, New York
-Age at study initiation: 8 weeks
-Weight at study initiation: 230 - 290 grams
-Fasting period before study: no data
-Housing: In pairs in stainless steel wire-mesh cages
-Diet: ad lib. (except during exposure)
-Water: ad lib. (except during exposure)
-Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
-Temperature (°C): 23 +/- 2
-Humidity (%): 50 +/- 10
-Air changes (per hr): no data
-Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
nose only
Vehicle:
other: unchanged (no vehicle)
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
-Exposure apparatus: K-TRON Model T-20 Twin Screw Volumetric Feeder
-Exposure chamber volume: 6000 mL
-Method of holding animals in test chamber: Rats were restrained in stainless steel cylinders with conical nose piece
-Source and rate of air: ca. 24 - 36 L/min
-Method of conditioning air: High pressure air jet
-System of generating particulates/aerosols: The air flow swept the suspended dust into the 6000 mL cyclonic elutriator. The cyclone removed the larger particles by impaction and allowed the smaller particles to enter a 38 L glass exposure chamber.
-Method of particle size determination: By Sierra Series 210 cascade impactor (MMAD and percent particles with aerodynamic diameters less than 10 um)
-Temperature, humidity, pressure in air chamber: Chamber temperature was measured with a mercury thermometer, relative humidity with a Bendix Model 566 psychrometer, and chamber oxygen content with a Biosystem Model 3100R oxygen analyser

TEST ATMOSPHERE
-Brief description of analytical method used: In 30 min intervals by gravimetric analyses. Known volumes of chamber atmosphere were drawn through pre-weighed Gelman glass fiber filters. Filters were weighed on a Cahn 28 automatic Electrobalance. Atmospheric concentrations were calculated from the filter weight gain, determined from the pre- and post-sampling filter weights.
-Samples taken from breathing zone: yes

VEHICLE
None, air only

TEST ATMOSPHERE
-Particle size distribution: as tabulated below
-MMAD / GSD: as tabulated below
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
Mean: 160, 480, 1100 and 2900 mg/m3
No. of animals per sex per dose:
6
Control animals:
no
Details on study design:
-Duration of observation period following administration: 14 days
-Frequency of observations and weighing: daily clinical observation and weighing of all survivors
-Necropsy of survivors performed: no data
Statistics:
LC 50 was calculated separately by Probit Analysis

Results and discussion

Effect levels
Sex:
male
Dose descriptor:
LC50
Effect level:
1 165 mg/m³ air
Based on:
test mat.
95% CL:
>= 590 - <= 2 909
Exp. duration:
4 h
Mortality:
160 mg/m3: 0/6
480 mg/m3: 1/6
1100 mg/m3: 3/6
2900 mg/m3: 5/6

All deaths occurred within 24 hours.
Clinical signs:
other: During or immediately following exposure, rats from all groups exhibited gasping, red nasal discharge, and compound-covered faeces. Rats from the >= 480 mg/m3 groups also exhibited laboured breathing. In addition, rats from the >= 1100 mg/m3 groups did no
Body weight:
Rats typically had slight to severe (up to 18 % of initial body weight) weight losses within 24 hours of exposure.
Gross pathology:
No data

Any other information on results incl. tables

Sodium Perborate Tetrahydrate Atmospheres / Mortality

 

Concentration (mg/m3)

% Particles < 10 um ADa

MMAD (um)b

Mortality

(# deaths/# exposed

Mean

SD

Range

160

23

140-210

94

3.3

0/6

480

130

280-640

94

3.5

1/6

1100

240

720-1500

93

3.5

3/6

2900

1500

870-4900

86

4.2

5/6

 

a: Percent by weight of particles with aerodynamic diameter (AD) less than 10 um

b: Mass median aerodynamic diameter

Applicant's summary and conclusion

Interpretation of results:
Category 4 based on GHS criteria
Remarks:
Migrated information
Conclusions:
The calculated LC50 in male rats over 4 hours was at 1165 mg/m3 of air.
Executive summary:

In this study, the 4 h inhalation ALC was calculated in male rats. Mean concentrations of Sodium Perborate Tetrahydrate were 160, 480, 1100 and 2900 mg/m3 and 6 males per dose were used. Mortality was dose-related and the ALC was determined with 480 mg/m3. The substance was classified as moderately toxic.

The LC50 (4 h) was calculated subsequent to the study report finalisation and was at 1165 mg/m3 (equivalent to toxicity category IV of GHS OECD or harmful according to Annex VI of Directive 67/548/EEC).