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Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Test performed according to GLP. 1 hour exposure rather than 4 hour (this has been accounted for in the calculation of the LD50 value). No analytical monitoring

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985
Report date:
1985

Materials and methods

Principles of method if other than guideline:
Ten albino rats were expsoed to the test substance at an atmospheric concentration of 200 mg/L. Animals were observed for a total of 14 days.
GLP compliance:
yes
Test type:
fixed concentration procedure

Test material

Constituent 1
Chemical structure
Reference substance name:
Bentonite, acid-leached
EC Number:
274-324-8
EC Name:
Bentonite, acid-leached
Cas Number:
70131-50-9
Molecular formula:
unspecified for this UVCB substance
IUPAC Name:
Bentonite, acid-leached
Details on test material:
- Name of test material (as cited in study report): Copisil D4A10 (bentonite acid leached)

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Suitable licence dealer
- Age at study initiation: 6 - 9 weeks
- Weight at study initiation: 226-292 g
- Housing: Galvanized cages with indirect bedding
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: At least 7 days


ENVIRONMENTAL CONDITIONS
- Temperature: 65 - 75°F
- Photoperiod: 12 hrs dark / 12 hrs light

Administration / exposure

Route of administration:
inhalation
Type of inhalation exposure:
whole body
Vehicle:
other: unchanged (no vehicle)
Details on inhalation exposure:
Animals were placed in a 95 L plexiglass chamber. A flow of air was passed through the chamber at a rate of 5 L/minute. The test article was introduced directly through the chamber inlet so it mixed with the incoming air.. The chamber was initially charged with the test article at a static concentration of 200 mg/L, and the test article introduced at regular intervals for a period of 1 hour so that a concentration of 200 mg/L was maintained for the 1 hour exposure
Analytical verification of test atmosphere concentrations:
no
Duration of exposure:
1 h
Concentrations:
200 mg/L
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: 1, 3, 6 and 24 hours after exposure and then daily for 14 days
- Necropsy of survivors performed: yes

Results and discussion

Effect levelsopen allclose all
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 200 mg/L air
Based on:
test mat.
Exp. duration:
1 h
Sex:
male/female
Dose descriptor:
LC50
Effect level:
50 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Mortality:
No mortalities occurred during the test
Clinical signs:
other: 1 animal had slight depression after 1 hour exposure. No clinical signs were noted thereafter
Body weight:
Bodyweights appeared normal at the end of the test
Gross pathology:
In animals 2 and 5 (males) an abscess was found on the left lobe of the lung; 2 cm in diameter, hard, yellow, pus filled. No gross changes were observed in the other animals.

Any other information on results incl. tables

Table 1: Acute inhalation toxicity (raw data)

Animal no and sex

Bodyweight (g)

1

3

6

24

2

3

4

5

6

7

8

9

10

11

12

13

14

Body weight (g)

1 M

274

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

422

2 M

282

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

396

3 M

280

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

356

4 M

258

SD

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

376

5 M

292

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

402

6 F

268

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

332

7 F

242

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

274

8 F

232

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

246

9 F

246

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

266

10 F

226

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

258

SD = Slight depression

N = Normal

The classification criteria for acute inhalation toxicity relate to a 4 hour experimental expousre period. Where LC50 values have been obtained in stuides using exposure durations shorter or longer than 4 hours these may be adjusted to a 4 hour equivalent using Habers law (Cn.t = k), where 'C' is the concentration, 'n' is a regression coefficient, t is the exposure time and 'k' is a constant. For extrapolation to longer duration it is recommended to set n = 1. Using Habers law the LC50 for the inhalation study is 50 mg/L.

Applicant's summary and conclusion

Interpretation of results:
not classified
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test material gave an LD50 of 200 mg/L after 1 hour exposure which can be extrapolated to an LC50 of 50 mg/L for a 4 hour exposure. Based on the classification criteria bentonite acid leached is not classified by the inhalation route in accordance with CLP Regulation (EC) no. 1272/2008