Diamond

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP conform study following OECD guidelines

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Diamond

EC Number:

231-953-2

EC Name:

Diamond

Cas Number:

7782-40-3

Molecular formula:

C

IUPAC Name:

carbon

Details on test material:

- Name of test material (as cited in study report): Synthetic Diamond Grade 2 (2 micron) Powder
- Substance type: inorganic
- Physical state: solid
- Lot/batch No.: 135-200-0125-99 E634%CU33%WT33% REACH

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Ace Animals, Inc., Boyertown, PA
- Age at study initiation: young adults(9-10 weeks)
- Weight at study initiation: males: 324-355 gr; females: 207-258gr.
- Housing: single housing in suspended stainless steel cages
- Diet (e.g. ad libitum): Purina Rodent Chow 5012
- Water (e.g. ad libitum): tap water
- Acclimation period: 18 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-22°C
- Humidity (%): 52-67%
- Photoperiod (hrs dark / hrs light): 12 hours light/dark cycle

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Nose-Only Exposure Chamber (Mini-Nose Only Inhalation Chamber, ADG Developments LTD)
- Exposure chamber volume: approximately 6.7 liters
- Method of holding animals in test chamber: Animals were individually housed in polycarbonate holding tubes
- Source and rate of air: air compressor ( JUN-AIR, Model #6-15); 28.4 Lpm
- Method of conditioning air: 3.3 Lpm of compressed mixing air. supplied using air from a compressed air tank (Airgas)
- System of generating particulates/aerosols: modified Wright Dust Generator driven by a variable speed motor (Dayton, Model #4Z538A) D.C. speed control with 0-100 potentiometer
- Method of particle size determination: eight-stage Andersen Cascade Impactor
- Temperature, humidity in air chamber: 20-22 °C, 34-43%,

TEST ATMOSPHERE
- Brief description of analytical method used: gravimetric
- Samples taken from breathing zone: yes

TEST ATMOSPHERE (if not tabulated)
- MMAD (Mass median aerodynamic diameter): MMAD average 2.3 µm

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

241 min

Concentrations:

4.45 - 5.78 mg/L
Average 5.20 ± 0.43 mg/L

No. of animals per sex per dose:

5 female and 5 males

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: 5 times in 14 days period
- Necropsy of survivors performed: yes
- Other examinations performed: body weight measured, clinical signs (daily)

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.2 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

241 min

Mortality:

All animals survived

Clinical signs:

other: No clinical signs

Body weight:

Although all animals lost body weight between Day 0 and Day 3, all rats gained weight over the entire course of the study

Gross pathology:

No gross abnormalities were noted for any of the tested animals

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information No labelling requirement for acute toxicity inhalation Criteria used for interpretation of results: other: OECD GHS and CLP

Conclusions:

Under the conditions of this study, the single exposure acute inhalation LC50 of Synthetic Diamond Grade 2 (2 micron) Powder, CAS No.: 1182-40-3 is greater than 5.20 mg,/L in male and female rats. In conformity with the criteria given in Annex VI to Commission Directive 2001/59/EC and according to Annex I of Regulation (EC) 1272/2008 and OECD-CHS (Globally Harmonized Classification System) the test item Synthetic Diamond Grade 2 (2 micron) Powder has no labelling requirement for acute toxicity inhalation.

Executive summary:

An acute inhalation toxicity test was conducted with rats to determine the potential for Synthetic Diamond Grade 2 (2 micron) Powder, CAS No.: 1182-40-3 to produce toxicity from a single exposure via the inhalation (nose-only exposure) route. Under the conditions of this study, the single exposure acute inhalation LC50 of the test substance is greater than 5.20 mg/L in male and female rats. After establishing the desired generation procedures during pre-test trials, ten healthy rats (5/sex) were exposed to the test atmosphere for 4 hours. Chamber concentration and particle size distributions of the test substance were determined periodically during the exposure period. The animals were observed for mortality, signs of gross toxicity, and behavioral changes at least once daily for 14 days following exposure. Body weights were recorded prior to exposure and again on Days 1,3,7 and 14 (termination). Necropsies were performed on all animals at terminal sacrifice.

All animals survived exposure to the test atmosphere. The gravimetric chamber concentration was 5.20 mg/L. Based on graphic analysis of the particle size distribution as measured with an Andersen Cascade Impactor, the mass median aerodynamic diameter was estimated to be 2.3 µm.

Immediately following exposure and throughout the 14-day observation period all animal appeared active and healthy. There were no signs of gross toxicity, adverse pharmacologic effects, or abnormal behavior. Although all animals lost body weight between Day 0 and Day 3, all rats gained weight over the entire course of the study. No gross abnormalities were noted for any of the animals when necropsied at the conclusion of the 14-day observation period.