2,4-dinitroanisole

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Study completed February 2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

Slight differences in temperature and humidity observed due to the heat required to generate DNAN aerosol. Due to the relatively short duration of the rats to
these slight temperature, humidity and oxygen disgressions, the environmental conditions with the exposure chamber were considered to be acceptable and did not affect the validity of the study

Deviations:

not applicable

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

The MMAD was higher than required ranges (1-4 um). It was due to the method of generation, which was a direct result of the physical properties of DNAN. It
is heated and generated as a condensation aerosol, which actually represented a realistic exposure scenario for individuals involved with this material in a
munition plant. Condensation aerosols make it difficult to control the particule size of the test atmosphere due to various factors (sublimation, condensate nuclei...). This deviation is considered to be acceptable for assessing the inhalation toxicity of DNAN.

Deviations:

not applicable

GLP compliance:

yes (incl. QA statement)

Test type:

fixed concentration procedure

Limit test:

yes

Test material

Test material information

1

Reference substance name:

2,4-dinitroanisole

EC Number:

204-310-9

EC Name:

2,4-dinitroanisole

Cas Number:

119-27-7

Molecular formula:

C7H6N2O5

IUPAC Name:

2,4-dinitroanisole

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: BAE Systems, Ordnance Systems, 4509 West Stone Kingsport, TN 37660 ; Batch number = 10DNAN9-9 ; lot number = BAE10>H281-008
- Expiration date of the lot/batch: N/A
- Purity test date: 100%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Solubility and stability of the test substance in the solvent/vehicle: Practically insoluble in water

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 Laboratories, Wilmington, Massachussets
- Females nulliparous and non-pregnant
- Age at study initiation: 7 weeks old
- Housing: singly in solid bottom polycarbonate boxes, suspended on a cage rack
- Diet : ad libitum, exept during the 4-hour exposure period
- Water :ad libitum , exept during the 4-hour exposure period
- Acclimation period: 5-day acclimatization

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 71 +/-0.6
- Humidity (%): 47 +/- 2.1

- Photoperiod (hrs dark / hrs light): a 12/ 12

Administration / exposure

Route of administration:

inhalation: mixture of vapour and aerosol / mist

Type of inhalation exposure:

nose only

Vehicle:

air

Mass median aerodynamic diameter (MMAD):

>= 1 - <= 10 µm

Geometric standard deviation (GSD):

>= 1.3 - <= 1.8

Remark on MMAD/GSD:

2 particles size samples collected from the 2 exposures
GSD for first sample : 1.8-1.8
GSD for second sample : 1.3-1.4
The desired MMAD for inhalation toxicology studies typically ranges from 1-4. However For this study it was higher than desired.
The reason for the increased particule size was due to the method of generation , which was a direct result of the physical properties of the test material which is a wax-like solid that could not be dispersed in the air as a dry powder.

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: a glass cylinder
- Exposure chamber volume: 36 liters
- Method of holding animals in test chamber: Only the heads of rats were positioned within the exposure chamber and their bodies were positioned outside the exposure chamber. Rats were positioned in the exposure cylinder such that their noses were at the conical end of the cylinder. in order to secure the rat in this position, a plastic disk with a hole in the center was inserted over the tail of each rat and positioned within the cylinder close to the base of the rat's tail so as to prevent the rat frombacking out of the rearof the cylinder. Each exposure cylinder was inserted into one of the holes in the faceplate of the exposure chamber such that the head of each rat extended into the exposure chamber (nose-only).


- Source and rate of air:10L/min
- Method of conditioning air: air was introduced via a port on the top of the exposure chamber to provide adequate test atmospheremixing in the chamber and to maintain oxygen levels above 19%
- System of generating particulates/aerosols: Chamber atmospheres of DNAN aerosol were generated dynamically in air within the exposure chamber. Test atmospheres were generated by heating powdered DNAN in a fabricated 3-neck glass generation vessel to approximately 270°C with a 600mL beaker heating mantle.
- Method of particle size determination: Measurement of the Mass Median Aerodynamic Diameter (MMAD)
- Treatment of exhaust air: Test atmospheres were exhausted through air impinger containing acetone to scrub the DNAN using a Radeco model AVS-28A vacuum pump prior to discharge into a fume hood.
- Temperature, humidity, pressure in air chamber: Chamber temperature for the exposures ranged from 21 to 25°C and were slightly outside of the targeted range of 22+/-2°C during certain periods of exposure. Chamber relative humidity for the exposures ranged from 15 to 33% and was slightly lower than the targeted range of 30 to 70% due to the heat required to generate DNAN aerosol.

TEST ATMOSPHERE
- Brief description of analytical method used: Numerous tube samples were collected in the line with the gravimetric sampling train and analyzed by gas chromatography to determine if vapor component was present. The gravimetric analysis was the most accurate method to characterize the condensation aerosol present in the chamber during the animal exposures.
- Samples taken from breathing zone: Atmospheric concentration of the DNAN condensation aerosol was determined during all inhalation exposures. A total of 10 to 17 samples were collecteded from the exposure chamber during each of the exposures.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

ca. 4 h

Remarks on duration:

Due to problems with the generation system, the first LC50 exposure was terminated approximately 2 hours early. Data not reported.

Concentrations:

0.73 +/- 0.10 mg/L and 2.4 +/- 0.25 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:
For the first LC50 inhalation exposure : rats were weighed on test days 1, 2, 3, 6, 8, 13 and 15. for the second LC50 inhalation exposure, at test days 1, 2, 3, 7, 10 and 15
Rats were observed approximately every hour during each oth the inhalation exposures and each day during the 14-day post-exposure
- Necropsy of survivors performed: yes
- Other examinations performed: clinicals signs of toxicity and gross pathological examination after euthanasia by carbon dioxide asphyxiation.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

>= 2.4 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality during the 4-hour exposure and subsequent 14-day recovery period.

Clinical signs:

other: During the exposure, most rats generally began to form a yellow crustaround their noses and on their whiskers within the first hour of exposure. The yellow crust remained throughoutthe exposure but did not appearto effect respiration. After removal from e

Body weight:

2 of 5 male rat exhibited a 1-2% weight loss and 4 of 5 female exhibited a 1-5% weight losson post-exposure day 1 but all animals began to gain weight at a normal rate by post-exposure day 2.

Gross pathology:

All animals exposed during the 2 LC50 exposures had minimal to mild yellow staining on various parts of the head, chest, and/or forearms at the time of necropsy.
One male rat exposed during the first LC50 exposure also had a mildly enlarged spleen.
One male rat exposed during the second LC50 exposure had mottled lungs with froth in the lower trachea and a second male rat had a slightly enlarged spleen.

Applicant's summary and conclusion

Interpretation of results:

Category 5 based on GHS criteria

Executive summary:

According to the Health Effects Test Guidelines OPPTS 870.1300, an acute inhalation toxicity study has been performed, using groups of 10 rats (5 male and 5 female), exposed nose-only to a 2.4 mg/L aerosol atmosphere of DNAN during 4 hours. The condensation aerosol atmosphere of DNAN has been obtained by heating powdered DNAN. By GC analysis, no significant vapor component was present in the chamber. 2.4 mg/L is the highest-achievable concentration of DNAN aerosol.

No test compound-related mortalities occured in rats exposed during the study and no adverse toxic signs, body wheight changes, or gross necropsy findings were observed in exposed rats after exposure and after a 14 -day observation period.

Therefore, the LC50 will be reported as > 2.4 mg/L.