Hydrocarbons, C9-16, hydrotreated, dearomatized

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable without restrictions because it was carried out in a method similar/equivalent to OECD TG 413.

Data source

Reference

Reference Type:

publication

Title:

A 90-day continuous vapor inhalation toxicity study of JP-8 jet fuel followed by 20 or 21 months of recovery in Fischer 344 rats and C57BL/6 mice

Author:

Mattie, D.R., Alden, C.L., Newell, T.K., Gaworski, C.L., Flemming, C.D.

Year:

1991

Bibliographic source:

Toxicologic Pathology 19(2):77-87

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

Deviations:

yes

Remarks:

Only 2 concentrations were used

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

most likely 8008-20-6

IUPAC Name:

most likely 8008-20-6

Constituent 2

Reference substance name:

JP-8 jet fuel

IUPAC Name:

JP-8 jet fuel

Test material form:

other: low viscosity liquid hydrocarbon

Details on test material:

- Name of test material (as cited in study report): JP-8 jet fuel
- Substance type:Kerosine
- Physical state: Liquid

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Rats: Charles River Breeding Laboratory, Wilmington, Massachusetts
- Age at study initiation: Approximately 10 weeks old
- Housing: gang-caged
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 to 25
- Humidity (%): 30 to 70%
- Photoperiod (hrs dark / hrs light): 12 hours dark/12 hours light

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus:Thomas Dome inhalation chambers (25 cubic meters) with heated glass evaporation towers through which the test material was passed, an air stream flowing through the tower carried the vapours into the main chamber
- Method of holding animals in test chamber: Each chamber housed numerous animals in stainless steel, wire-mesh cages.


TEST ATMOSPHERE
- Brief description of analytical method used: A gas chromatograph trace of the sample of each drum as it entered the exposure chamber to ensure consistency over the study period. A gas chromatograph trace was routinely obtained for each chamber every 2 weeks.
- Samples taken from breathing zone: yes/no

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

90 days

Frequency of treatment:

Constant (24 hours a day) for the 90 days

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 500, or 1000 mg/m3
Basis:
other: nominal conc. (vapour)

No. of animals per sex per dose:

95 male rats per dose; 75 female rats per dose

Control animals:

yes, sham-exposed

Details on study design:

- Dose selection rationale: Not reported
- Rationale for selecting satellite groups: Not reported
- Post-exposure recovery period in satellite groups: Male rats: 2 weeks, 2 months, 9 months, and 21 months; female rats: 9 and 21 months
- Section schedule rationale (if not random): Not reported

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: No data


DETAILED CLINICAL OBSERVATIONS: No data


BODY WEIGHT: Yes on rats; no on mice
- Time schedule for examinations: Biweekly


FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data


FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data


WATER CONSUMPTION: No


OPHTHALMOSCOPIC EXAMINATION: No


HAEMATOLOGY: Yes
- Time schedule for collection of blood: At the end of exposure period, 2 weeks and 2 and 21 months after exposure termination
- Anaesthetic used for blood collection: No data
- Animals fasted: Yes
- How many animals: All rats sacrificed at the end of exposure; 10 male rats per group at 2 weeks and 2 months; 10 male rats and 10 female rats at final sacrifice (21 months)
- Parameters measured were not specified.


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood:At the end of the exposure period, 2 weeks and 2 and 21 months after exposure termination
- Animals fasted: No data
- How many animals: All rats sacrificed at the end of the exposure period; 10 male rats per group at 2 weeks and 2 months; 10 male rats and 10 female rats at final sacrifice (21 months)
- Parameters measured were not specified.


URINALYSIS: Yes
- Time schedule for collection of urine: Pre-exposure and at each scheduled sacrifice
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters measured were only specified as including cell count and osmolarity.


NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes, a detailed list of tissues was not provided and it is stated that approximately 40 tissues per animal were fixed for routine histopathology.

Other examinations:

Rat liver, kidney, and spleen were weighed.

Statistics:

A repeated measures analysis of variance was used to analyze body weights. Possible differences between the sexes were examined using a 2-way analysis of variance. Haematology, clinical chemistry, and organ weights were analyzed using a 2 or 3 factorial analysis of variance. Bonferoni correction was used where appropriate. Tumour data were analysed using a chi-square test for proportions and an Armitage Test for Trends. Bonferoni corrections of the Fisher Exact Test or Bates Exact Chi-square were used where appropriate. The Kaplan-Meier product-limit method was used for survival distribution, which was then analyzed with the Mantel-Cox statistic. A p less than 0.05 was used to determine significance.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

effects observed, treatment-related

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY: In rats, there were no effects on clinical signs or mortality. In mice, necrotising dermatitis associated with fighting occurred in both sexes, but lead to an increase mortality in treated mice from 2 weeks to 9 months after cessation of treatment.


BODY WEIGHT AND WEIGHT GAIN: Male rats had a significant and dose-dependent decrease in body weight (table 1) during exposure, which remained lower than the controls throughout the 21-month recovery period.

HAEMATOLOGY: There were no biologically significant changes in haematology.


CLINICAL CHEMISTRY: There were no biologically significant changes in clinical chemistry.


URINALYSIS: There was a dose-dependent increase in urinary renal epithelial cell numbers in male rats (only group measured) with an increase in incidence and severity at the end of the exposure period. However, this was reversed by the after a 2 week recovery period.


ORGAN WEIGHTS: There was a significant increase in absolute and relative kidney weight in male rats at the end of the 90-day exposure period (table 1). This was not observed at the 9-month recovery period, but after a 21-month recovery period relative kidney weights were significantly increased in the low-dose group and absolute and relative kidney weights were significantly increased in the high-dose group. Kidney weights were not affected in the female rats.


HISTOPATHOLOGY: NON-NEOPLASTIC: Both male rat treatment groups developed hydrocarbon-induced nephropathy (table 2), which included exacerbated hyaline droplet formation, granular casts in the outer medulla, and increased incidence and severity of lesions undifferentiable from those of chronic progressive nephrosis. The hyaline droplet response was resolved by the 2 week recovery period and the granular casts were resolved after 9 or 21 months of recovery. However, the lesions of chronic progressive nephrosis and the linear mineralization in the inner medulla continued to increase in incidence and severity throughout the recovery period. There were no other significant histopathological findings.


HISTOPATHOLOGY: NEOPLASTIC: Although there was a slight increase in thyroid C cell adenomas in the females (14, 16, and 27% in the control, low- and high-dose group, respectively), the findings were not significant and the combined incidence for thyroid neoplasms in the control group exceeded the expected incidence for this strain and age.

Effect levels

1

Dose descriptor:

LOAEL

Effect level:

500 mg/m³ air (nominal)

Sex:

male

Basis for effect level:

other: Body weight; organ weights; and histopathology. These effects were due to alpha-2u globulin-mediated nephropathy.

2

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/m³ air (nominal)

Sex:

female

Basis for effect level:

other: overall effects

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

 

Table 1

Body and kidney weights in male rats
90-day exposure
	n	Control	n	500 mg/m^3	n	1000 mg/m^3
Body weight	13	308 ± 5	15	293 ± 5 *	14	283 ± 5 **
Kidney weight	13	2.0 ± 0.03	13	2.5 ± 0.06 **	13	2.9 ± 0.06 **
Kidney/Body weight	13	0.7 ± 0.01	13	0.9 ± 0.01 **	13	1.0 ± 0.02 **
9-month recovery
Body weight	10	416 ± 10	10	405 ± 5	10	397 ± 6 *
Kidney weight	10	2.7 ± 0.05	10	2.6 ± 0.05	10	2.8 ± 0.09
Kidney/Body weight	10	0.6 ± 0.01	10	0.7 ± 0.01	10	0.7 ± 0.02
21-month recovery
Body weight	10	440 ± 9	10	370 ± 10 **	10	376 ± 9 **
Kidney weight	10	3.2 ± 0.15	10	3.1 ± 0.16	10	3.6 ± 0.23 **
Kidney/Body weight	10	0.7 ± 0.04	10	0.9 ± 0.06 **	10	1.0 ± 0.09 **

* p<0.05

** p<0.01

 

Table 2

Kidney histopathology in male rats (incidence and severity)
90-day exposure
	Hyaline droplets	Chronic progressive nephrosis	Granular casts	Linear papilla mineralization	Urothelial hyperplasia
Control	100% (1.5)	82% (0.4)	0	0	0
500 mg/m^3	100% (4)	100% (1.1)	100% (2)	0	0
1000 mg/m^3	100% (4)	100% (2)	100% (2.2)	57% (0.6)	0
2-week recovery
Control	86% (1)	43% (0.4)	0	0	0
500 mg/m^3	100% (0.7)	100% (0.8)	100% (1.6)	71% (0.7)	0
1000 mg/m^3	100% (0.7)	100% (1.2)	100% (2.5)	88% (0.7)	0
2-month recovery
Control	100% (1.0)	83% (0.4)	0	0	0
500 mg/m^3	100% (1.0)	100% (1)	100% (0.5)	86% (0.8)	0
1000 mg/m^3	100% (1.1)	100% (1.3)	100% (0.5)	100% (1)	0
9-month recovery
Control	75% (0.4)	100% (0.6)	0	0	0
500 mg/m^3	100% (0.4)	91% (1.3)	14% (0.4)	100% (1.2)	14%
1000 mg/m^3	100% (0.4)	100% (1.5)	13% (0.4)	100% (1.7)	13%
21-month recovery
Control	29% (0.5)	100% (3)	0	0	18%
500 mg/m^3	11% (0.4)	100% (3.9)	0	100% (2)	78%
1000 mg/m^3	0	100% (4.7)	0	100% (2.4)	100%

 

Applicant's summary and conclusion

Conclusions:

Male rats developed hydrocarbon-induced nephropathy and decreased body weight. Therefore, the LOAEL in male rats is 500 mg/m3. There were no significant treatment-related effects in female rats; therefore, the NOAEL in female rats is greater than or equal to 1000 mg/m3. However, effects seen in male rats were due to alpha-2u globulin-mediated nephropathy, and, as such, are not relevant to human exposure.

Executive summary:

In a 90-day inhalation toxicity study, JP-8 jet fuel was administered to 95 male Fisher 344 rats and 75 female Fischer 344 rats per concentration by dynamic whole body exposure at concentrations of 0, 500 or 1000 mg/m³(0, 0.5, or 1.0 mg/L) for 24 hours per day, 7 days/week for a total of 90 days. At the end of the exposure period 15 rats/sex/concentration were sacrificed. The remaining animals were periodically sacrificed over a 2 year period.

 

The male rats developed hydrocarbon-induced nephropathy at both treatment concentrations. Male rats had decreased body weight and decreased absolute and relative kidney weight at both treatment concentrations. Female rats were unaffected by treatment.  The NOAEL for male rats is difficult to establish, since potential adverse effects may be masked by male rat specific hydrocarbon nephropathy. However, based on the hydrocarbon-induced nephropathy and reduced body weights and increased kidney weights, the LOAEL in male rats is 500 mg/m³. These effects are not relevant for human exposure.  The NOAEL for female rats is greater than or equal to 1000 mg/m³. 

This study received a Klimisch score of 1 and is classified as reliable without restrictions because it was carried out in a method similar/equivalent to OECD TG 413.