Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam-stripped

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1985

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study was conducted by a GLP accredited laboratory using a method similar to OECD Testing Guideline 403 and meets acceptable scientific standards

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1986

Report date:

1986

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

Nose-only exposure would have been more relevant considering the properties of the substance

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Distillates (petroleum), light catalytic cracked

EC Number:

265-060-4

EC Name:

Distillates (petroleum), light catalytic cracked

Cas Number:

64741-59-9

IUPAC Name:

64741-59-9

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): Light catalytic cracked distillate (petroleum)
- Substance type: Hydrocarbons having carbon numbers predominantly in the range of C9 through C25. Also contains relatively large portion of bicyclic aromatic hydrocarbons
- Physical state: Light brown liquid

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 breeding laboratories , Inc
- Age at study initiation: at least 9 weeks
- Weight at study initiation: Males: 250-300g, Females: 200-250g
- Housing: Individual stainless steel and glass chambers of 0.25cubic meter volume
- Diet: ad libitum except during exposure periods, purina certified laboratory chow 5002
- Water: ad libitum
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-24°C
- Humidity (%): 50-68%
- Photoperiod (hrs dark / hrs light): 12 hour light/12 hour dark

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Source and rate of air: 1.7-2.9cfm
- System of generating particulates/aerosols: DeVilbliss No. 40 nebulizer
- Method of particle size determination: Cascade impactor
- Temperature, humidity, pressure in air chamber: temperature: 21-24°C, humidity: 50-68%

TEST ATMOSPHERE
- Samples taken from breathing zone: yes

TEST ATMOSPHERE: tabulated

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

ca. 4 h

Concentrations:

2.34, 3.47, 5.06, 6.34 and 7.29mg/l

No. of animals per sex per dose:

five rats per sex per dose

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observed daily and weighed prior to exposure as well as day 7 and 14
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Results and discussion

Preliminary study:

A Phase I study was done where 5 young adult rats of each sex were exposed to a target aerosol concentration of 5.0mg/l for 4 hours. No animals died during the exposure to a time weighted average (TWA) concentration of 5.06 ±0.29mg/l; however, three males and one female died during the 14 day observation period, necessitating conduct of phase II in an attempt to define the LC50 of the test material aerosols.

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

4.65 mg/L air

Based on:

test mat.

95% CL:

>= 3.89 - <= 5.55

Exp. duration:

4 h

Remarks on result:

other: Calculated using Litchfield and Wilcoxon method

Mortality:

No animals died during the course of the exposure. Three males and one female died during the 14 day observation period following the Phase I trial level exposure, which necessitated conduct of phase II. A number of animals from groups exposed to concentrations of 2.34mg/l and higher died either one or two days post exposure. All of the animals exposed to a concentration of 7.29mg/l of test material aerosols died.

Clinical signs:

other: Most of the exposed animals displayed some hair coat abnormalities and many of them at the higher exposure levels showed a crust around the nose 2 to 4 days post exposure. A number of rats of both sexes developed skin abnormalities late in the observation

Body weight:

There was a dose-related suppression in body weight gain in the day 7 weighing that was still apparent in the animals that survived to the terminal necropsy, especially the males.

Gross pathology:

The three males and one female that died the day after phase I exposure exhibited dark red lungs, blood-tinged stains around the nose and stained coats, but animals surviving to term appeared normal. Similar gross necroscopy observations were made on most of the higher exposure level phase II rats, group 3 (7.29mg/l) and group 5 (6.34mg/l) and in the two rats that died after exposure to lower levels.

While the changes seen in the lungs of the phase I animals that were killed terminally were mild, morphologic changes in the four animals that died were severe. There was congestion and edema with extravastion of red blood cells accompanied by necrosis of alveolar lining cells. They also exhibited spotty necrosis of bronchiolar epithelium, particularly of small bronchioles. These morphologic changes were severe enough to have caused death, while those seen in the surviving animals were indicative of recovery.

The histologic changes seen in the phase II animals that died one to two days post exposure duplicated those of the early death phase I animals, while animals surviving to term exhibited changes that were generally mild and chronic in nature. Interstitial inflammation, focal alveolar histocytosis, and localized emphysema seemed to be related to exposure level. a few skin lesions were seen in both phase I and phase II animals.

These histologic changes in animals that died are indicative of deep irritation and were considered to be compatible with acute hydrocarbon toxicity. They were severe enough to be the cause of death.

Any other information on results incl. tables

Mortality data

Phase and GroupNumber	Measured concentration TWA (mg/l)	Mortality
		Male		Female		Total
		Number	Percent	Number	Percent	Number	Percent
PII-G1	0.00	0	0	0	0	0	0
PII-G2	2.34	1	20	0	0	1	10
PII-G4	3.47	0	0	1	20	1	10
PI-G1	5.06	3	60	1	20	4	40
PII-G5	6.34	3	60	5	100	8	80
PII-G3	7.29	5	100	5	100	10	100

Mean body weight data expressed as a percentage of pre-exposure data

Phase and group number	Measured concentrationTWA (mg/l)	Pre-exposure body weight day 0 (%)	Body weight expressed as percentage of day 0 weight
			Male		Female
			Day 7	Day 14	Day 7	Day 14
PII-G1	0.00	100	111.2	120.4	107.0	113.2
PII-G2	2.34	100	99.6	113.4	105.2	108.4
PII-G4	3.47	100	100.4	111.4	100.1	105.8
PI-G1	5.06	100	99.7	116.4	99.3	111.5
PII-G5	6.34	100	92.1	103.2	-	-
PII-G3	7.29	100	-	-	-	-

Frequency of occurance of pharmatoxic signs

Pharmacotoxic sign	0mg/l		2.34mg/l		3.47mg/l		5.06mg/l		6.34mg/		7.29mg/l
	M	F	M	F	M	F	M	F	M	F	M	F
Oily coat	0	0	5	5	5	4	5	5	3	1	0	2
Wetness on coat	0	0	5	5	5	5	5	5	5	5	5	5
Crust around nose (red or otherwise)	0	0	2	0	1	4	4	5	1	2	0	3
Hair loss	1	1	4	1	1	0	2	4	2	0	0	0
Skin abnormal (scabs, flaky)	2	1	4	0	3	0	2	4	2	1	0	0
Trembling	0	0	1	0	0	1	0	0	0	0	0	0
Nasal discharge/wet	0	0	0	0	4	3	0	0	0	0	4	2
Urine stain on coat	0	0	2	0	1	1	0	1	3	1	0	0
Rapid breathing	0	0	0	0	0	0	1	0	0	0	0	1
Decreased activity/mobility	0	0	0	0	5	5	0	0	2	3	0	3
Eye abnormalities (partially or fully closed, crust around)	0	0	1	0	0	5	0	2	2	0	0	1
Discharge (forelimb)	0	0	0	0	1	0	0	0	0	0	0	0

Applicant's summary and conclusion

Interpretation of results:

harmful

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute inhalation median lethal dose (LD50) of the test item in the male and female Sprague-Dawley rat strain was estimated to be 4.65mg/l for both sexes. The test substance meets the criteria for classification as Acute Tox 4 Acute Tox 4 according to Regulation (EC) No.1272/2008 on the Classification, Labelling and Packaging of Substances and Mixtures.

Executive summary:

The acute toxicity: inhalation of the registered substance was determined using a method similar to the OECD Guideline for Testing of chemicals 403. Inhalation of the aerosolized read-across substance by male and female rats at a TWA concentration of about 5.1mg/l for 4 hours was acutely toxic, resulting in the death of three of 5 males and one of 5 females within a couple days of exposure. All the animals showed some pharmacotoxic signs during the first few post exposure days and these were more severe in females. Histopathalogic lesions of the lung were interpreted to have resulted from exposure to a deep irritant, but surviving animals showed recovery. Since 4 deaths occurred at this trial level exposure, phase II was carried out at a target dose level of 0,2.5, 3.5, 6.25 and 7.5mg/l. Measured TWA concentrations ranged from 2.34 to 7.29mg/l. One animal died at each of the two lower test compound level, while all 10 rats exposed to the highest level died 1 to 2 days post exposure, with intermediate numbers succumbing at the other dose levels. Gross and histologic lesions seen in the animals that died mirrored those seen in phase I. The combined male and female data gave a value of 4.65mg/l for the LC50, with a 95% confidence limits of 3.89 to 5.55mg/l. The test substance meets the criteria for classification as Acute Tox 3 according to Regulation (EC) No.1272/2008 on the Classification, Labelling and Packaging of Substances and Mixtures.