Propiononitrile

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 December 1981 - 19 March 1982

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

The substance vapour was administered to male and female Sprague-Dawley rats over an approximate 14-week period, 6 hours per day, 5 days per week for a maximum of 63 days of exposure. Toxic effects were monitored by observing gross signs of toxicity, body weight, haematology and clinical chemistry values, and gross pathological and histopathological changes in the test animals. Groups of xx male and female rats were exposed to target concentrations of 0, 60, 120 or 210 ppm in air. Samples for stability analysis were obtained from the bottom of each used container and the top of each newly opened container. The rats were placed invidually in wire mesh cages suspended in an inhalation cage rack. The exposure atmospheres were generated by bubbling nitrogen through the substance using a glass bubbler.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Propiononitrile

EC Number:

203-464-4

EC Name:

Propiononitrile

Cas Number:

107-12-0

Molecular formula:

C3H5N

IUPAC Name:

propanenitrile

Test material form:

liquid

Specific details on test material used for the study:

Purity: 96%
Physical state: Liquid
Specific gravity: 0.78
Colour: Dark brown

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Qurantined for at least 10 days prior to start of study. On the first day of study the rats were 43 days of age.
Animals were invidually housed in suspended stainless steel wire mesh cages and given food and water ad libitum except during exposure periods. Animal rooms were mainted at 70-74°F and 35-60% relative humidity with a 12-hour light/12-hour dark cycle.

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

air

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Mean nominal and analytical values for the 3 exposure levels were:

Concentration (ppm)
Exposure Groups 1 (Low) 2 (Mid) 3 (High)
Target Levels 60 120 210
Nominal (±SD) 56 ± 8.8 119 ± 16.9 203 ± 19.6
Analytical (±SD) 60.2 ± 1 120.3 ± 1.1 209 ± 1.3
Nominal/Analytical Ratio 0.93 0.99 0.97

Duration of treatment / exposure:

63 days

Frequency of treatment:

6 hours per day, 5 days per week

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 ppm

Doses / concentrations 2

Dose / conc.:

60 ppm

Doses / concentrations 3

Dose / conc.:

120 ppm

Doses / concentrations 4

Dose / conc.:

210 ppm

No. of animals per sex per dose:

Fifteen/sex/dose

Control animals:

yes

Examinations

Observations and examinations performed and frequency:

Animals were observed between the second and fifth hour of each exposure, and an estimation was made of the percentage of animals exhibiting hypoactivity, irritation of the eyes, and breathing difficulties. All animals were also individually examined for gross signs of toxicity preceding and following each exposure and checked for mortality on non-exposure days. Each animal was weighed and given a thorough examination for gross signs of toxicity on a weekly basis.

Sacrifice and pathology:

Terminal body weights were obtained just prior to euthanasia was completed by exsanguination. Detailed necropsies were conducted on all rats which died during the course of the study, those that were sacrificed in moribund condition and those terminated at the end of the study. The following tissues were placed in a solution of 10% neutral buffered formalin for fixation (eyes were placed in a solution of 2% glutaraldehyde and 10% neutral buffered formalin): abdominal aorta, adrenal glands, bone and bone marrow (femur), brain (longitudinal section), esophagus, eyes (with optic nerve), ovaries, testes (with epididymis), heart, colon, ileum, kidneys, liver, lung, lymph node (mesenteric), mammary gland, nasal turbinates, pancreas, thyroid/parathyroid, pituitary, prostate, salivary gland, sciatic nerve, skeletal muscle, skin, spinal cord, spleen, stomach, thymus, trachea, urinary bladder, uterus (with cervix), gross lesions.

Other examinations:

Haematology, Clinical chemistry.

Statistics:

In-life and terminal body weights and organ weight data were analysed by the use of Dunnetts test for comparison of results from trated groups with those of controls.
Organ-to-body weight ratios were analysed by the use of the Mann-Whitney test with the Bonferroni Inequality.
The frequency of microscopic lesions in the treated groups as compared to controls was evaluated by use of Fisher's exact test with Bonferroni Inequality.
Non-categorical haematology and serum and urine chemistry data were statistically examined by Dunnett's test for the comparison of multiple treatments with a control and by inspection. Categorical data were examined to determine any remarkable group differences.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Hypoactivity, irritation of the conjunctiva, and breathing difficulties were observed in the high exposure animals during the actual expoure period.
Numerous sigsn of toxicity were observed at the pre- and post-exposure observation checks which were dose-dependent: laboured breathing, nasal discharge, salivation, discharge from the eyes, hypoactivity and alopecia. Additional observations included arching of the back, pilorection, biting, pawing or rubbing the cage, ataxia, tremors or convulsions, scabs and one palpable mass on the abdomen.

Mortality:

mortality observed, treatment-related

Description (incidence):

Three high exposure level males died or were sacrificed in extremis during the study.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Significant decreases in body weight were seen in high levels males throughout the study and in high level females for most of the study.
Mid-level males showed signifcant body weight decreases at two time points during the study when compared to control animals.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

Males and females at all exposure levels had statistically significant decreases in red blood cells and/or haemoglobin values.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

There were marginal increases in females serum thiocyanate concentrations in low level males and females with a return to baseline in the mid and high level exposure groups.
Decreased BUN concentrations were observed in high exposure groups.
There were statistically significant elevations of alkaline phosphatase, SGOT and SGPT in high level males and alkaline phosphatase in high level females.

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

Urine-thiocyanate concentrations increased in all treated groups with similar or higher values in mid-level as compared to high level males and females.
A notable dose-response diuresis was also seen.

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Statistical increase in the weights of heart, liver and spleen (males only) were seen.
Statistical decrease in the testes was seen.

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no lesions seen during the necropsy which were considered to be related to chemical exposure.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

The only microscopic change which was apparently related to substance administration was mildly increased haemosiderin deposition in spleens of 10/15 high level females and 11/15 mid-level females. Other microscopic changes were considered to be spontaneous due to similar frequencies of occurrence in control and treated groups or due to the common occurrence of these changes in thsi strain of rat.

Effect levels

Key result

Dose descriptor:

LOAEC

Effect level:

60 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

haematology

Target system / organ toxicity

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

60 ppm

System:

other: Haematology - Males and females at all exposure levels had statistically significant decreases in red blood cells and/or haemoglobin values.

Organ:

spleen

Treatment related:

yes

Dose response relationship:

yes

Relevant for humans:

not specified

Applicant's summary and conclusion

Conclusions:

The substance caused deaths in 20% of the high level males and increases in spleen weight, spleen to body weight ratio and decreases in erythrocyte count and haemoglobin concentration occurred in animals from the low concentration group. Therefore, the LOAEC for this study is considered to be 60 ppm. A NOAEC could not be identified.

Executive summary:

Male and female Sprague-Dawley (15/sex/concentration) rats were exposed to mean analytical substance concentrations of 0, 60, 120 and 209 ppm for six hours per day. five days per week for fourteen weeks (maximum of 63 exposure days). Mortality occurred for males only at the highest concentration (20% died or were sacrificed in extremis during the first four weeks). Body weights were significantly lower for high level animals compared to controls throughout the study and were also decreased , not always significantly, for mid level males. Clinical observations seen during the study included hypoactivity, signs of nasal and ocular irritation, and breathing difficulties. The observations were usually dose-related, occurring primarily at mid and high level concentrations. Blood analyses showed several haematological changes including significantly lower erythrocyte counts and haemoglobin concentrations for high level males and mid and high level females. Serum changes included decreased blood urea nitrogen and increased alkaline phosphatase concentrations in high level males and females and increased serum glutamic oxaloacetic trasaminase concentrations in high level males. Histopathological findings included increased haemosiderin deposition in spleens of mid and high level females. This, together with the haematological findings suggest increased erythrocyte destruction in treated animals. Increases in spleen weight, spleen to body weight ratio and decreases in erythrocyte count and haemoglobin concentration occurred in low level animals. Therefore, the LOAEC for this study is considered to be 60 ppm. A NOAEC could not be identified.