Activated Carbon - Low Density Skeleton

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 May 1980 - 28 May 1980

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

Study seems to be conducted according to a method that equals OECD guideline 403, which was not yet adopted at that time. It is unclear if GLP conditions are maintained during study. Report is concise but clear. Due to the limitations of the study and its read-across purpose ( in accordance with the ECHA Practical guide #6 on the reporting of read-across in IUCLID), the study was assigned a Klimisch 2 rating.

Justification for type of information:

The justification for read across is attached as a separate document to the "Toxicological information" summary

Cross-reference

Reason / purpose for cross-reference:

read-across source

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1980

Report date:

1980

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

Remarks:

(guideline was not yet adopted in 1980)

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Activated Carbon - High Density Skeleton

EC Number:

931-328-0

Molecular formula:

C

IUPAC Name:

Activated Carbon - High Density Skeleton

Details on test material:

- Name of test material (as cited in study report): BPL 12 x 30
- Physical state: Solid (black fine powder)
- Lot/batch No.: Confidential information

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, Massachusetts
- Weight at study initiation:
Male: 251-285 g
Female: 227-239 g
- Housing: During exposure in a 100 liter plexiglass exposure chamber

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Bubbler
- Exposure chamber volume: 100 liter
- Source and rate of air:
Source 1: 10 L/min through calibrated flow meter into bubbler
Source 2: 14 L/min into bubbler (1 sec/13 seconds)
Air was diluted with 10 L/min before directed into exposure chamber
- System of generating particulates/aerosols: Three-neck bubbler

TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetry
- Samples taken from breathing zone: no, only directly from the center sampling port

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: No data
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): No data

Analytical verification of test atmosphere concentrations:

no

Duration of exposure:

1 h

Concentrations:

Nominal exposure concentration: 64.4 mg/L
Mean airborne test material concentration (gravimetry): 8.5 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:
Observations: before exposure, every 15 minutes during exposure, hourly for 4 hours after exposure and daily thereafter
Body weights: on day 0, 1, 2, 4, 7 and 14
- Necropsy of survivors performed: yes
- Other examinations performed: gross necropsy

Statistics:

Not relevant

Results and discussion

Preliminary study:

Not relevant

Effect levels

Effect levels 1

Sex:

not specified

Dose descriptor:

LC100

Effect level:

235 mg/L air (nominal)

Exp. duration:

1 h

Remarks on result:

other: All animals died (initial test)

Effect levels 2

Key result

Sex:

male/female

Dose descriptor:

LC0

Effect level:

64.4 mg/L air (nominal)

Exp. duration:

1 h

Remarks on result:

other: No deaths, but multiple effects were observed (contamination of fur, general stress, lung rales, weight loss, lung discoloration)

Effect levels 3

Key result

Sex:

male/female

Dose descriptor:

LC0

Effect level:

8.5 mg/L air (analytical)

Exp. duration:

1 h

Remarks on result:

other: No deaths, but multiple effects were observed (contamination of fur, general stress, lung rales, weight loss, lung discoloration)

Mortality:

No mortality was observed.

Clinical signs:

other: Animals visible exhibited labored breathing and intermittent gasping. Upon removal from the chamber mucoid nasal discharge, salivation, rapid or labored breathing, gasping, dry or moist rales, reduced activity, and wet or matted ano-genital fur were obser

Body weight:

Weight losses were seen in nearly all rats following exposure. Body weights recovered to pre-exposure values in males by day 4 and in females usually by day 7. Body weight in the second week were within the limits of normal expectation.

Gross pathology:

At necropsy, 5 male and 4 female rats showed treatment related foci or areas of lung discoloration (higher incidence than normally encountered)

Other findings:

Not relevant

Applicant's summary and conclusion

Interpretation of results:

other: not classified

Remarks:

based on CLP criteria

Conclusions:

A one-hour inhalation exposure of rats to a dust of BPL 12 x 30 at a nominal concentration of 64.4 mg/L and mean airborne concentration of 8.5 mg/L did not produce mortality. However, irritation of the respiratory mucous membranes related to test material exposure was observed and residual lung discoloration was seen at necropsy. The LC50 was established to be >8.5 mg/L.

Executive summary:

This acute inhalation toxicity study in rats was conducted according to a method resembling OECD guideline 403. Male and female rats were exposed for one hour to BPL 12 x 30 at a nominal concentration of 64.4 mg/L and a mean airborne concentration of 8.5 mg/L. Rats were observed for 14 days after exposure.

Several effects were observed. All rats appeared heavily contaminated with the test material during and 14 days after the exposure period. Animals visible exhibited labored breathing and intermittent gasping. Upon removal from the chamber mucoid nasal discharge, salivation, rapid or labored breathing, gasping, dry or moist rales, reduced activity, and wet or matted ano-genital fur were observed. Recovery was apparent within 1 day. Slight dry rales was observed in most rats during the 14-day observation period. Weight losses were seen in nearly all rats following exposure. Body weights recovered to pre-exposure values in males by day 4 and in females usually by day 7. Body weights in the second week were within the limits of normal expectation. At necropsy, 5 male and 4 female rats showed foci or areas of lung discoloration.

As no deaths occured the tested concentration can be considered as LC0 (LC50 >8.5 mg/L). Following these results, the test substance does not need to be classified for acute inhalation toxicity according to the criteria outlined in Annex I of 1272/2008/EC .