2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 2010 - February 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Fully GLP- and guideline compliant

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

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

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine

EC Number:

426-040-2

EC Name:

2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine

Cas Number:

25713-60-4

Molecular formula:

C 21 H 6 Br 9 N 3 O 3

IUPAC Name:

tris(2,4,6-tribromophenoxy)-1,3,5-triazine

Details on test material:

Name of test material (as cited in study report): "BTAC-245".
Chemical names: 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine
Hill formula: C21H6Br9N3O3
CAS No: 25713-60-4
Lot No.: 100907
Appearance: White solid.
Conditions of storage: Room temperature.
Stability at conditions of storage: No data available.
Expiry date: Unknown.

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 Deutschland GmbH, Sulzfeld, Germany.
- Age at study initiation: 8 to 9 weeks at time of administration.
- Weight at study initiation: mean body weight: female: 240.2 g, male: 337.0 g
- Housing: Single caging in Makrolon cages type III (37.5 cm x 21.5 cm x 18 cm). Wire mesh lids.
- Diet (e.g. ad libitum):Ssniff R/M-H maintenance diet for rats and mice (item V1534-300) ad libitum, supplied by Ssniff Spezialdiäten GmbH, 59494 Soest, Germany. Analysis of the feed for ingredients and contaminants is performed randomly by Ssniff.
- Water (e.g. ad libitum): Tap water, acidified with HCl to a pH of >3, from an automatic watering system, ad libitum.
- Acclimation period: At least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Median = 20.4°C, Range = 20.1 to 20.8 °C
- Humidity (%): Median = 49.3 %, Range = 45.3 to 52.8 %.
- Air changes (per hr): About 12 / h.
- Photoperiod (hrs dark / hrs light): Artificial light from 6 a.m. to 6 p.m.

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: Head Nose Only Exposure Unit from TSE-Systems GmbH, Bad Homburg, Germany
- Exposure chamber volume: 24 L
- Method of holding animals in test chamber: In ten of the twenty openings of the chamber, the inhalation tubes with the animals were situated.
- Source and rate of air: The air with the dust (17 L/minute) was inserted via the central opening on top of the chamber.
- Method of conditioning air: The test substance was pressed to a round powder cake of 46 mm diameter with a force of 2000 kg. In the dust
generator acc. to Budiman a scraper rotates over the surface of the powder cake and removes the powder which is then transported by an air stream. The desired dust concentrations are obtained by controlling the feed rate of the scraper.
- Method of particle size determination: The size of the dust particles was analysed twice during the exposure with a cascade impactor
(Berner-Impaktor Type LPI4/0,06/2 from Hauke KG, Gmunden, Austria). It contains nine steps with cut-off- diameters from 0.06 µm to 16 µm.
- Temperature, humidity, pressure in air chamber: see attachment

TEST ATMOSPHERE
- Brief description of analytical method used:
The amount of test substance was measured by gravimetric analysis.
The dust was collected in plastic pipette-tips filled with cotton-wool which were inserted into the inhalation facility through a separate hole. The inner diameter of the tips was 7 mm. The velocity in the tips was 0.9 m/sec. The exact amount of collected air was measured by the mass controller of the inhalation device.
Each filter-tip was dried and weighed before sampling. After sampling dry air
(< 10 % humidity) was passed through them to remove possible moisture. The difference in the weights before and after sampling divided by the volume of air sampled is the concentration of the dust.
- Samples taken from breathing zone: yes (a separate hole)


TEST ATMOSPHERE
- Particle size distribution: see attachment
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): see attachment

Analytical verification of test atmosphere concentrations:

yes

Remarks:

The amount of test substance was measured by gravimetric analysis.

Duration of exposure:

4 h

Concentrations:

The actual test substance concentration: 1.47 mg/L

The nominal concentration, i.e. the amount of test substance powder used per volume of air was 43.5 mg/L.
So 3.4 % of the used test substance was present as dust, the rest was deposited in the inhalation device.

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: on day 1, 3, 7 and 14 after exposure
- Necropsy of survivors performed: yes
- Other examinations performed: necropsy including a gross pathological examination.

Statistics:

The LC50 and its 95 % confidence limits were calculated by the method of moving averages according to W. THOMPSON (Bact. Rev. 11, 1947, 115ff) (not applicable with a limit test).

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 1.47 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

All animals survived till the end of the study.

Body weight:

The body weight development was inconspicuous. The body weight loss the first days after the expose which was seen in most animals is caused by the restraining in the inhalation tube and not necessarily test substance related. One week after the exposure all but two females gained weight compared to the day of the exposure. The second week all animals gained weight.

Gross pathology:

Nothing abnormal was seen in any of the animals

Any other information on results incl. tables

Preliminary experiments

Before starting the test, the following experiments were made to obtain more information about the test substance:

·        It was tried to produce a dust with an actual concentration of about 5 mg test substance dust per litre.

·        It was tried to reduce the size of the dust particles.

 

Results:

The dust concentration of 5 mg/L could not be obtained. With the TSE-Dust Feeder according to Budiman and a coarse separator for larger particles a dust concentration of about 1.2 mg/L could be obtained with the highest useful feed rate of the dust generator. The mean aerodynamic diameter (MMAD) of the test substance dust was 6.6 µm and thus higher than the recommended 4 µm. Therefore it was tried to grind the test substance in a ball mill. But by the forces in the ball mill the test substance powder became solid and sticks on the wall and on the balls of the mill. So, probably due to the softness of the test substance, grinding in such a device is not possible.

Therefore the higher MMAD was accepted. A more stringent separator for larger particles was not used as the limit concentration of 5 mg/L could not be reached and each additional separator decreases also the concentration of small particles.

Applicant's summary and conclusion

Conclusions:

The inhalation exposure of rats to "BTAC-245" at the maximal technically feasible concentration of 1.47 mg/L did not produce signs of toxicity.
All animals survived and no adverse effects were observed during the 14-day observation period.
The LC50, per inhalation, four hours exposure, of "BTAC-245" for male and female rats is therefore greater than 1.47 mg per litre air
which is the highest technically feasible dust concentration.

Executive summary:

Design of the study

"BTAC-245"was administered as dust per inhalation to Sprague Dawley rats. The test substance was applied for 4 hours in a nose-only inhalation device. The target concentration for a limit test according to the guideline of 5 mg/L could not be obtained. Therefore the maximal technical feasible concentration was administered. The actual concentration of the dust was 1.47 mg per litre air. 5 male + 5 female animals were used. The chamber was operated with 17 L air/dust per minute. Chamber temperature ranged from 19.9 to 20.8 °C, the relative humidity from 0.5 to 1.3 %. The chamber air was not humidified as this could impede the dust generation.

 

Methods and investigations were performed in conformance with the OECD-Guideline 403, "Acute Inhalation Toxicity" from September 7, 2009 and with the Council Regulation (EC) No 440/2008, method B.2.

 

Results

Mortality

All animals survived till the end of the study.

 

Observations in life

All animals were normal during the 14 days of the observation period.

 

Body weight

The body weight development was inconspicuous. The body weight loss the first days after the expose which was seen in most animals is caused by the restraining in the inhalation tube and not necessarily test substance related. One week after the exposure all but two females gained weight compared to the day of the exposure. The second week all animals gained weight.

Post mortem findings

All animals were normal at the scheduled necropsy.

Sex differences

No sex differences can be established from the results of this study.

Dust characterisation 

mean actual concentration (mg/L)	1.47
MMAD (mm)	9.1 and 10.8
GSD	6.8 and 4.9
chamber volume (L)	24
air flow (Lpm)	17.2

 

The actual dust concentration was the highest technically feasible dust concentration.

The mass median aerodynamic diameter (MMAD) was higher than the recommended range of 1 to 4 µm but grinding of the test substance was not possible as the test substance became solid in a ball mill.

  

Conclusion

The inhalation exposure of rats to "BTAC-245" at the maximal technically feasible concentration of 1.47 mg/L did not produce signs of toxicity. All animals survived and no adverse effects were observed during the 14-day observation period.

The LC50, per inhalation, four hours exposure, of "BTAC-245" for male and female rats is therefore greater than 1.47 mg per litre air which is the highest technically feasible dust concentration.