Barium oxide (BaO), solid soln. with calcium oxide, magnesium oxide, phosphorus oxide (P2O5), strontium oxide and zinc oxide, copper-doped

Endpoint summary

Description of key information

REACH Annex VII column 2 states that testing by the inhalation route is appropriate if exposure of humans via inhalation is likely. Forming insoluble particulate matter, the inhalation route was considered the most appropriate exposure pathway for strontium apatite, copper doped. A reliable (Klimisch 1), GLP compliant, OECD Guideline 436 study was conducted for the test item (Haferkorn 2017). CD/Crl(SD) rats (3 male; 3 female) were exposed to an aerosol dust of strontium apatite, copper doped at a gravimetrically determined concentration of 5.06±0.02 mg/L air for 4 hours by inhalation, via nose-only exposure. The dust particles had a Mass Median Aerodynamic Diameter (MMAD) or 1.752 µm and a Geometric Standard Deviation (GSD) or 2.32. Under the test conditions in the study, 4-hour inhalation exposure induced slight dyspnoea until 3 hours post exposure in all rats. No other clinical signs of toxicity, mortality or pathological changes at necropsy, were observed in the treated rats. Therefore, under the conditions of the test, the LC50 value for rats following inhalation of strontium apatite, copper doped for 4 hours was determined as >5.06 mg/L air.

Key value for chemical safety assessment

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 May 2017 - 26 June 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REACH Annex VII column 2 states that testing by the inhalation route is appropriate if exposure of humans via inhalation is likely. Forming insoluble particulate matter, the inhalation route was considered the most appropriate exposure pathway for strontium apatite, copper doped.

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)

Version / remarks:

Adopted September 7, 2009

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.52 (Acute Inhalation Toxicity - Acute Toxic Class Method)

Version / remarks:

Commision Regulation (EC) No. 260/2014 method B.52, published in the Official Journal of the European Union, dated March 19, 2014

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No. of test material: sponsor lot# 116/08/15
- Expiration date of the lot/batch: November 2020
- Purity test date: 21 January 2016

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Composition: SrO 69.28%; P2O5 26.08%; CuO 3.48%; BaO 0.55%
- Particle size parameters: Diameter (D) 10% = 0.40 µm; D50% = 1.62 µm; D90% = 3.64 µm
- Physical characteristics: Powder
- Storage condition of test material: At ambient temperature (10 - 25°), container kept tightly closed and stored in a dry and well-ventilated place.

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: males approx. 8 weeks and females approx. 9 weeks
- Weight at study initiation: males (237 - 249 g); females (228 - 232 g)
- Fasting period before study: Feeding was discontinued 16 hours before exposure
- Housing: MAKROLON cages (type III plus)
- Diet: Commercial diet, ssniff R/M-H V1534 ad libitum
- Water: tap water ad libitum
- Acclimation period: At least 5 adaption days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 55 ± 10%
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): 12:12 hours dark/light cycles at 150 lux

IN-LIFE DATES: From: 24 May To: 26 June 2017

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

clean air

Mass median aerodynamic diameter (MMAD):

1.752 µm

Geometric standard deviation (GSD):

2.32

Remark on MMAD/GSD:

The generated dust particles had a mass median aerodynamic diameter (MMAD) of 1.752 µm, as determined with a cascade impactor. The Geometic Standard Deviation (GSD) of the MMAD was 2.32.

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: RHEMA-LABORTECHNIK dynamic inhalation apparatus (6579 Hofheim/Taunus, Germany)
- Exposure chamber volume: 28.5 L
- Method of holding animals in test chamber: Animals held in pyrex tubes at edge of the chamber in radial position for nose-only exposure.
- Source and rate of air: The generator was fed with compressed air (5.0 bar) from a compressor (ALUP Kompressorenfabrik, 73257 Köngen, Germany). At the bottom of the exposure chamber, the air was sucked off at a lower flow rate, in order to produce a homogenous distribution and positive pressure in the exposure chamber (inflow 900 L/h, outflow 800 L/h). A manometer and air-flow meter (ROTA Yokogawa GmbH & Co. KG), were used to control supply and exhaust, respectively. Flow rates were checked hourly.
- System of generating particulates/aerosols: rotating brush dust generator
- Method of particle size determination: Cascade impactor 6.0 L/min (Article No. 700800-CI-060), TSE Systems GmbH, 61352 Bad Homburg, Germany)
- Temperature, humidity, pressure in air chamber: Temperature (22.8°C ± 0.1°C) and humidity (57.6% ± 0.2%) were measured once every hour with a climate control monitor (testo 175-HZ data logger).

TEST ATMOSPHERE
- Brief description of analytical method used: The dust from the exposure chamber was drawn through the cascade impactor for 1 minute at a constant flow rate of 5 L/min. The slides were removed from the impactor and weighed on an analytical balance (SARTORIUS, type 1601 004, precision 0.1 mg).
- Samples taken from breathing zone: yes. Dust samples were taken once every hour during the exposure. For that purpose, a probe was placed close to the animals’ noses and air was drawn through the air sample filter at a constant flow of air of 5 L/min for 1 minute. The filters were weighed before and after sampling.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Remarks on duration:

In accordance with OECD Guideline 436

Concentrations:

Nominal concentration: 5 mg/L
Measured concentration: 5.06 mg/L +- 0.02

No. of animals per sex per dose:

3 males, 3 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: During and following exposure, clinical examinations were made daily. Individual weights of animals were determined once during the acclimatisation period, before the exposure on test day 1, on test days 2, 4, 8 and 15. Changes in weight were calculated and recorded at 1 day, and at the end of the test.
- Necropsy of survivors performed: yes. Necropsy of all animals was carried out and all gross pathological changes were recoded for each animal, with particular attention to any changes in the respiratory tract.
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other: Cageside observations included, but were not limited to: changes in the skin and fur, eyes, mucous membranes, respiratory, circulatory, autonomic and central nervous system, as well as somatomotor activity and behaviour pattern. Particular attention was directed to observation of tremor, convulsions, salivation, diarrhoea, lethargy, sleep and coma.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.06 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

not determinable due to absence of adverse toxic effects

Mortality:

No mortality was observed

Clinical signs:

other: Under the present test conditions, a 4-hour inhalation exposure to Strontium apatite, copper doped at a concentration of 5.06 mg/L air induced slight dyspnoea until 3 hours post exposure in all rats. This effect was considered to be clinical signs of gene

Body weight:

No influence in body weight gain was noted.

Gross pathology:

No pathological findings were observed at necropsy in any of the male or female rats (n=6).

Interpretation of results:

GHS criteria not met

Conclusions:

Under the present test conditions, the LC50 value for rats following inhalation of strontium apatite, copper doped for 4 hours was determined as >5.06 mg/L air. According to the Globally Harmonised Classification System (GHS), the test item does not require classification for acute inhalation toxicity.

Executive summary:

CD/Crl(SD) rats (3 male; 3 female) were exposed to an aerosol dust of strontium apatite, copper doped at a gravimetrically determined concentration of 5.06±0.01 mg/L air for 4 hours by inhalation, via nose-only exposure. The dust particles had a Mass Median Aerodynamic Diameter (MMAD) or 1.752 µm and a Geometic Standard Deviation (GSD) or 2.32. Under the present test conditions, 4-hour inhalation exposure induced slight dyspnoea until 3 hours post exposure in all rats. No other clinical signs of toxicity, mortality or pathological changes at necropsy, were observed in the treated rats.

Under the present test conditions, the LC50 value for rats following inhalation of strontium apatite, copper doped for 4 hours was determined as >5.06 mg/L air. Conducted according to OECD 436 and GLP, the study was considered reliable without restriction (Klimisch 1).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

5.06 mg/m³

Quality of whole database:

A regulatory designed study conducted in accordance with GLP

Additional information

Under REACH Annex VII, an acute toxicity study via the oral route of exposure is required. Column 2 of Annex VII permits waiving of acute oral toxicity testing if a study on acute toxicity by the inhalation route is available.

Forming insoluble particulate matter, the inhalation route was considered the most appropriate exposure pathway for strontium apatite, copper doped. Exposure to strontium apatite, copper doped via the oral route is unlikely, therefore further testing is not recommended.

Justification for classification or non-classification

Forming insoluble particulate matter, the inhalation route was considered the most appropriate exposure pathway for strontium apatite, copper doped. An acute inhalation study via the acute toxic class method (OECD 436) was conducted. Under the present test conditions, the LC50 value for rats following inhalation of strontium apatite, copper doped for 4 hours was determined as >5.06 mg/L air. Conducted according to OECD 436 and GLP, the study was considered reliable without restriction (Klimisch 1) and sufficient to determine classification. According to the Globally Harmonised Classification System (GHS) and EU CLP criteria, the test item does not require classification for acute inhalation toxicity.