Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report date:
2013

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Qualifier:
according to guideline
Guideline:
EU Method B.2 (Acute Toxicity (Inhalation))
GLP compliance:
yes (incl. QA statement)
Test type:
fixed concentration procedure
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
1,4-diethylbenzene
EC Number:
203-265-2
EC Name:
1,4-diethylbenzene
Cas Number:
105-05-5
Molecular formula:
C10H14
IUPAC Name:
1,4-diethylbenzene
Test material form:
other: liquid
Details on test material:
Purity 99.3% (GC Method MS 409 A.M)

Test animals

Species:
rat
Strain:
Crj: CD(SD)
Sex:
male/female
Details on test animals or test system and environmental conditions:
Diet
Commercial diet, ssniff® R/M-H V1534 (ssniff Spezialdiäten GmbH, 59494 Soest, Germany; see Appendix 2: Composition of the diet) served as food. Feeding was discontinued approx. 16 hours before administration; only tap water was then available ad libitum.
Periodic analysis of the food for contaminants based on EPA/USA is conducted at least twice a year by LUFA-ITL (see Appendix 2: Limitation for contaminants in the diet).

Housing
Granulated textured wood (Granulat A2, J. Brandenburg, 49424 Goldenstedt, Germany) was used as bedding material for the cages. The cages were changed and cleaned twice a week.
Periodic analysis of the bedding material for contaminants based on EPA/USA is conducted at least once a year by LUFA-ITL (see Appendix 2: Limitation for contaminants in the bedding material).
During the 14-day observation period the animals were kept by sex in groups of 2 and 3 animals in MAKROLON cages (type III plus) at a room temperature of 22°C ± 3°C and a relative humidity of 55% ± 15%. Deviations from the maximum range caused for example during cleaning procedures are dealt with in SOPs.
The rooms were lit (150 lux at approx. 1.50 m room height) and darkened for periods of 12 hours each.

Drinking water
Drinking water in bottles was offered ad libitum.
Drinking water is examined according to the 'Deutsche Trinkwasserverordnung 2001' [German Regulations on drinking water 2001] by the Hamburger Wasserwerke, 20539 Hamburg, Germany, at least four times a year (see Appendix 2: Limitation for contaminants in the drinking water).
In addition, drinking water samples taken at LPT are analysed by LUFA-ITL once a year for means of bacteriological investigations according to the 'Deutsche Trinkwas¬ser-verordnung 2001, Anlage 1' [German Regulations on drinking water 2001, Addendum 1].
Certificates of analysis of diet, drinking water and bedding material are QAU archived.

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
air
Details on inhalation exposure:
The study was carried out using a dynamic inhalation chamber (air changes/h (≥ 12 times)) with a nose-only exposure of the animals according to KIMMERLE & TEPPER . The apparatus consists of a cylindrical exposure chamber (volume 40 L) which holds the animals in pyrex tubes at the edge of the chamber in a radial position.
The aerosol of the test item was generated using a spray-jet .
The spray-jet was fed with compressed air (5.0 bar) from a compressor and with the test item using an infusion pump .
At the bottom of the exposure chamber, the air was sucked off at a lower rate than created by the dust generator in order to produce a homogenous distribution and a positive pressure in the exposure chamber (inflow 900 L/h, outflow 800 L/h).
A manometer and an air-flow meter were used to control the constant supply of compressed air and the exhaust, respectively. Flow rates were checked hourly and corrected if necessary.
The oxygen content in the inhalation chamber was 21% v/v. It was determined at the beginning and at the end of the exposure with a DRÄGER Oxygen-analysis test set (DRÄGER Tube Oxygen 67 28 081).
The whole exposure system was mounted in an inhalation facility to protect the laboratory staff from possible hazards.
The exhaust air was sucked through gas wash-bottles.
Exposure started by locating the rats into the exposure chamber after equilibration of the chamber concentration for 15 minutes.

Actual mean concentration of 1,4-Diethylbenzene (mg/L air): 5.02

Air flow entrance (L/h): 900
Air flow exit (L/h): 800
Air change (changes per hour): 22.5
Analytical verification of test atmosphere concentrations:
yes
Remarks:
HPLC
Duration of exposure:
4 h
Concentrations:
Limit Test: One concentration of 3 males and 3 females each
Full Test: 3 concentrations of 5 males and 5 females each
No. of animals per sex per dose:
Limit Test: 6 animals (3 males and 3 females)
Control animals:
no

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5 mg/L air
Based on:
act. ingr.
Exp. duration:
4 h
Mortality:
None of the animals died prematurely.
Clinical signs:
other: Under the present test conditions, a 4-hour exposure to 1,4-Diethylbenzene at the concentration of 5.02 mg/L air revealed slight to severe ataxia, slight to moderate tremor and slight dyspnoea immediately until 60 minutes or 3 hours after end of exposure
Body weight:
All animals gained the expected body weight.
Gross pathology:
No pathological findings were noted at necropsy.

Any other information on results incl. tables

Table 1 Summarized results, Acute inhalation toxicity study of 1,4 -diethylbenzene in rats

 Symptoms/Criteria     5.02 mg 1,4 -diethylbenzene/L air
   males, n=3  females n=3
 clinical signs:    
 ataxia  slight to severe / 0min-3h /3 animals affected    slight to severe / 0min-3h /3 animals affected
 tremor  moderate to severe / 0min-60min/ 3 animals affected    moderate to severe / 0min-60min/ 3 animals affected
 dyspnoea  slight / 0min-3h /3 animals affected   slight / 0min-3h /3 animals affected
 mortality:    
 within 3 h  0 0
 within 24 h  0  0
 within 7 d  0  0
 within 14 d  0  0
 mean body weight (in g):    
 start  256.3  231.7
 after 7 days  290.7 (+13.4% body weight gain compared with start value)  237.7 (+2.6% body weight gain compared with start value)
 after 14 days   338.3 (+32% body weight gain compared with start value)  251.0 (+8.3% body weight gain compared with start value) 
 inhibition of body weight gain  none  none
 necropsy finding  none  none

Applicant's summary and conclusion

Interpretation of results:
not classified
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Under the present test conditions, the LC50 value for rats following inhalation of 1,4-Diethylbenzene for 4 hours was determined as follows (actual concentration):

LC50 males and females combined (24 hours and 14 days): exceeding 5.02 mg 1,4-Diethylbenzene/L air for 4 hours (actual concentration).

According to the EC-Commission directive 67/548/EC and its subsequent amendments on the approximation of the laws, regulations and administrative provision relating to the classification, packaging and labelling of dangerous substances and the results obtained under the present test conditions,

1,4-Diethylbenzene requires no labelling as LC50 > 5 mg/L.

Also, according to the EC Regulation 1272/2008 and subsequent regulations, the test material does not require classification for acute inhalation toxicity.