Butan-1-ol

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Evaluation Of Subchronic Toxicity Of n-Butyl Acetate Vapor.

Author:

David, R.M., Tyler, T. R., Ouellette, R., Faber, W.D., Banton, M. I., Garman, R.H., Gill, M.W. and O’Donoghue, J.L.

Year:

2001

Bibliographic source:

Fd. Chem. Toxicol. 39: 877-886, 2001

Reference 2

Reference Type:

secondary source

Title:

Evaluation Of Subchronic Toxicity Of n-Butyl Acetate Vapor.

Author:

David, R.M., Tyler, T. R., Ouellette, R., Faber, W.D., Banton, M. I., Garman, R.H., Gill, M.W. and O’Donoghue, J.L.

Year:

2001

Bibliographic source:

Fd. Chem. Toxicol. 39: 877-886, 2001; cited in the OECD SIDS dossier 2008 of CAS 109-60-4, propyl acetate

Reference 3

Reference Type:

study report

Title:

Unnamed

Year:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OTS 798.2450 (90-Day Inhalation Toxicity)

Deviations:

yes

Remarks:

tissues from central and peripheral nervous system were not examined histologically

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

N-butyl acetate

EC Number:

204-658-1

EC Name:

N-butyl acetate

Cas Number:

123-86-4

Molecular formula:

C6H12O2

IUPAC Name:

butyl acetate

Specific details on test material used for the study:

- Analytical purity determined by GC

Test animals

Species:

rat

Strain:

Sprague-Dawley

Remarks:

CRL:CD(SD)BR/VAF Plus

Details on species / strain selection:

Rats were chosen as common representative species for the study.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Kingston, USA
- Females nulliparous and non-pregnant: yes
- Age at study initiation: ca. 60 d
- Mean weight at study initiation: 271+/-7 g (males); 215+/-8 g (females); the variability in body weight of individual animals in the selected population did not exceed 20 % of the mean for each sex
- Fasting period before study: no, food and water were not available during study
- Housing: Animals were housed in an Association for the Assessment and Accreditation of Laboratory Animal Care International-accredited vivarium; non-exposure period: individually in stainless-steel, wire-mesh cagesbin room seperated from exposure room
- Diet: Certified Rodent Diet (Agway Prolab RMH 3200 ground chow), ad libitum; not available during exposure
- Water: filtered municipal tap water from Monroe County (NY) water authority, ad libitum; not available during exposure
- Acclimation period: 12 days

DETAILS OF FOOD AND WATER QUALITY:
No known contaminants which would interfere with the outcome of this study were present in the feed. There have been no contaminants identified in previous water analyses that would be expected to interfere with the conduct of the study. Food analyses and semiannual analyses of water are maintained on file within the testing laboratory.

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 67-75
- Humidity (%): 46-60
- Photoperiod (hrs dark / hrs light): 12/12

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: 4200 L stainless-steel and glass NYU-type inhalation chambers (Hinners or Laskin chamber)
- Source and rate of air: filtered, compressed air
- Method of conditioning air: The test atmosphere was generated by metering the test substance into glass distillation columns packed with glass beads; for the 1500 and 3000 ppm chambers, two serial distillation columns were used whereas only one column was used for the 500 ppm concentration. Filtered, compressed air was passed through the glass bead-packed columns to evaporate the test substance. The test substance delivery rate and air flow rate were adjusted to produce the desired. The distillation columns were heated to ~ 50 °C to enhance vaporization.
- Temperature, humidity, pressure in air chamber: The temperature and humidity were maintained at 20.6–24.7 °C and 36.7–68.7 % under negative pressure.
- Air change rate: 12–14 air changes per h
- Method of particle size determination: Micro Laser Particle Counter (model /xLPC-301, Particle Measuring Systems, Inc., Boulder, CO)
- Other:
The oxygen content of the chamber exposure atmosphere was at least 19.0 %.

TEST ATMOSPHERE
- Brief description of analytical method used: Chamber vapor concentrations were monitored with a multipositional air sampling and analysis system. The system consisted of a single MIRAN® IA infrared gas analyzer (Wilks Foxboro Analytical, South Norwalk, CT) and a computer-operated four-port sampling valve (Valco Instruments, Houston, TX). Each chamber was sampled at least once per hour.
- Samples taken from breathing zone: not specified


The animals were individually housed in the chamber, and their location within the chamber was moved periodically according to a defined rotation scheme to eliminate any effect due to placement in the chamber.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Chamber vapor concentrations were monitored with a multipositional air sampling and analysis system at least once each hour with an infrared gas analyzer set at a wavelength of 3.38 µm.
The nominal concentration was calculated by dividing the amount of test substance consumed from the reservoir (determined gravimetrically) by the total chamber air flow.

Duration of treatment / exposure:

6 h/day

Frequency of treatment:

5 days per week (Monday to Friday) for 13 consecutive weeks (65 days), surviving animals were exposed for 1 (male) or 2 (females) days in week 14.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

500 ppm

Doses / concentrations 2

Dose / conc.:

1 500 ppm

Doses / concentrations 3

Dose / conc.:

3 000 ppm

No. of animals per sex per dose:

15

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
The exposure concentrations were based on data from a two-week inhalation probe study of male rats exposed to 0, 750, 1500, or 3000 ppm of the test substance for two weeks. This study demonstrated that the test substance produced concentration-related reductions in general activity levels during exposure periods. Animals appeared to acclimate to the 750 and 1500 ppm concentrations but not to 3000 ppm. Mean body weights for the female 1500 ppm animals and for the 3000 ppm male and female animals were lower than the control group on Days 7 and 14, but no statistically significant differences were noted. Based on these results, 3000 ppm was selected as an exposure concentration that would produce overt signs of toxicity and 500 ppm was selected as an exposure concentration that was expected to have no effect. An exposure concentration of 1500 ppm was selected as the intermediate exposure concentration.
For 500 ppm the target analytical concentration was increased to 550 ppm due to varying concentrations at different places in the chamber, so that the actual exposure to the animals would be closer to 500 ppm.

Positive control:

Not conducted.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: once a day on weekends
- Cage side observations included, but were not limited to, examination of the hair, skin, eyes and mucous membranes, motor activity, feces, urine, respiratory system, circulatory system, autonomic nervous system, central nervous system, and behavior patterns. Tapping on chamber to assess animals response was done.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: before and after exposure (during handling)

BODY WEIGHT: Yes
- Time schedule for examinations: weekly prior to exposure; fasted body weights were measured after exsanguination but prior to necropsy

FOOD CONSUMPTION AND COMPOUND INTAKE:
Food consumption was measured weekly prior to exposure, on Day 7, 14 and weekly afterwards.
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/animal/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Not specified

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

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: prior to the start of the study; last week of exposure
- Dose groups that were examined: before study all animals; last exposure week from control and high-concentration group (No changes were detected in the eyes of the high-concentration animals and therefore the animals from the low- and mid-concentration were not examined.)

HAEMATOLOGY: Yes
- Time schedule for collection of blood: day 30, day after last exposure
- Anaesthetic used for blood collection: Yes, Metofane
- Animals fasted: Yes
- How many animals: day 30: 5 male and 5 female of each group, after last exposure: all remaining animals
- Whole blood samples were analyzed for red blood cell count, total white blood cell counts, hemoglobin, hematocrit and red blood cell. Prothrombin time was measured. Slides with blood smears were stained and examined for cellular morphology, differential white blood cell count and platelet count.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: day 30, day after last exposure
- Animals fasted: Yes
- How many animals: day 30: 5 male and 5 female of each group, after last exposure: all remaining animals
- Serum samples were analyzed for total protein, total bilirubin, calcium, phosphorous, urea nitrogen, creatinine, glucose, gamma-glutamyltransferase, aspartate aminotransferase, alanine aminotransferase, sorbitol dehydrogenase and alkaline phosphatase. Albumin concentration and isozyme profile were determined. The albumin/globulin ratio was calculated from total protein and albumin concentrations. Serum sodium, chloride and potassium concentrations were measured.

URINALYSIS: Yes.
Urine was assessed as part of the cage side observations but parameters and methods of analysis were not further specified.

NEUROBEHAVIOURAL EXAMINATION: Yes
Neurobehavioural examinations were assessed as part of the cage side observations but parameters and methods of analysis were not further specified.

IMMUNOLOGY: No

Sacrifice and pathology:

GROSS PATHOLOGY: GROSS PATHOLOGY: Yes.
- Collected tissues are listed in table 1
- Wet weights of the liver, kidneys, testes or ovaries, spleen, adrenal glands, lungs and brain were recorded for all animals at necropsy. Paired organs were weighed together, except for the testes, which were weighed individually.

HISTOPATHOLOGY: Yes
- H&E stained tissues are indicated in table 1.
- All those tissues were examined microscopically from the control and high-concentration groups. In addition, the lungs, nasal passages, thymus (males only), stomach (females only), and gross lesions were examined from the mid-and low-concentration groups.

Other examinations:

The left testis and left epididymis of each male rat were placed into individual bags and frozen at - 25 °C. The right testis was preserved in 10 % buffered formalin. Both frozen and preserved samples of testes and epididymis were submitted to Research Triangle Institute, Research Triangle Park, NC for sectioning and evaluation of sperm morphology and development. The results are expressed per gram tissue weight.

Statistics:

Mean values were calculated for analytical concentration, chamber temperature, chamber relative humidity, body weight, feed consumption, serum chemistry, hematology, and organ weights. Body weight, feed consumption, serum chemistry, hematology, organ weight and sperm count data were evaluated using the following statistical tests: Bartlett’s test (P<=0.01), one-way analysis of variance (ANOVA) (P<=0.05), and Duncan’s multiple range test (P<=0.05) or Dunnett’s test to indicate statistical significance. If the Bartlett’s test indicated unequal variances, the data were evaluated using the Kruskal–Wallis H-test and the Mann–Whitney U-test. A probability of P<=0.05 (two-tailed) was used to determine significance. If the Bartlett’s test indicated unequal variances, the data were evaluated using the Kruskal–Wallis H-test and the Mann–Whitney U-test.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

3000 ppm: reduced activity levels (less movement, decreased alertness, and slower response) of generally minor severity during exposure, sialorrhea in 3 animals for no more than 1-2 exposure days, red discoloration of the chin hair in several females for no more than 1-2 exposure days
1500 ppm: normal for 5 h on day 0, normal for 1-2 h on day 1 and 2, afterwards reduced activity of generally minimal severity for the remainder of the daily exposure periods and all following exposures. Reduced activity of minimal severity was generally seen throughout daily exposures thereafter.
500 ppm: no observed effects

Mortality:

no mortality observed

Description (incidence):

No spontaneous mortality occurred during the study.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

- 3000 ppm: body weight significantly lower (P≤0.05) than control starting from day 7 (males) and 14 (females), weight gain were 62 % (male) and 78 % (female) of control group weight gain, body weight gain significantly lower (P≤0.05) than control (males: week 1, 2, 5-7; females: week 2, 4, 6)
- 1500 ppm: body weight significantly lower (P≤0.05) than control starting from day 42 (males) and 14 (females), weight gain were 77 % (male) and 70 % (female) of control group weight gain, body weight gain significantly lower (P≤0.05) than control (males: week 11; females: week 2)
- 500 ppm: not significantly different than control, weight gain were 90 % (male) and 107 % (female) of control group weight gain

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

- 3000 ppm: food consumption significantly lower (P≤0.05) than control during whole time for males and except day 84 and 91 for females, mean weekly feed consumption was 14-25 % (males) and 6-16 % (females) lower than the control group
- 1500 ppm: food consumption significantly lower (P≤0.05) than control (males: day 7, 35, 42, 49 56, 63, 70, 77, 84; females: all except day 91); mean weekly feed consumption was 4-17 % (males) and 10-15 % (females) lower than the control group
- 500 ppm: food consumption significantly lower (P≤0.05) than control (males: day 35, 42, 63, 70; females: day 7, 14); mean weekly feed consumption was 3-12 % lower for males and between 2 % higher and 7 % lower for females than the control group

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

no effects observed

Description (incidence and severity):

No changes were detected in the eyes of the high-concentration animals, therefore the animals from the low- and mid-concentration groups were not re-examined.

Haematological findings:

no effects observed

Description (incidence and severity):

hematologic parameters after 30 days :
No significant differences in hematologic parameters were seen after 30 days in all groups.
hematologic parameters after 90 days:
- 3000 ppm: significantly higher mean erythrocyte counts, hemoglobin concentration and hematocrit values after 90 days compared to control, mean eosinophil percentage (male only) was significantly higher
- 1500 ppm: no effects observed
- 500 ppm: no effects observed

blood cell morphology after 30 days
Spherocytosis and poikilocytosis were seen in blood smears of animals from most groups.
- 3000 ppm: polychromasia in 2 females, Howell-Jolly bodies in blood and anisocytosis in 1 female
- 0 ppm (control): polychromasia in 1 male
blood cell morphology after 90 days
Poikilocytosis was seen in blood smears of animals from groups.
- 1500 ppm: microcytosis in 1 male, anisocytosis
- 500 ppm: microcytosis in 1 male, spherocytosis in 2 males, anisocytosis
- 0 ppm (control): anisocytosis

All the values were within normal limits for rats of this age and for the age and strain of the animals used, therefore none of the differences were considered biologically significant.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

The observed changes were not considered to be toxicologically meaningful.
3000 ppm: significantly lower (approx. 1 Meq/L) mean sodium concentrations after 30 days, significantly lower mean albumin and total protein concentrations in females after 90 days
1500 ppm: significantly lower (< 4 Meq/L) mean chloride concentrations after 30 days, significantly higher mean sorbitol dehydrogenase activity in males after 90 days
500 ppm: no effects observed

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Description (incidence and severity):

No effects were described besides those observed as clinical signs.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

3000 ppm: absolute liver, kidney, brain (male only) and spleen weights significantly lower than control; relative organ weights only significantly lower for spleen (male only); significantly higher relative brain, lungs and testes weight in males and adrenal gland weight for males and females
1500 ppm: absolute liver, kidney (female only) and spleen weights significantly lower than control; no effects on relative organ weights observed; significantly higher relative brain and adrenal gland weight in females and testes in males
500 ppm: no effects observed

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

No exposure-related changes were detected on necropsy examination of male rats. Hemorrhage involving the glandular stomach (minimal severity) was observed in two 3000 ppm female rats. White discoloration in the non-glandular stomach was also observed for these animals. No changes were seen in female rats from the 1500 and 500 ppm groups.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

3000 ppm: changes observed in nasal passage (degeneration of olfactory epithelium, mild to moderate) and stomach; Olfactory epithelium was replace in some areas by transitional or respiratory epithelium. 3/10 female rats had acute inflammation and degenerative lesions (minimal to mild) of the stomach mucosa (glandular vs forestomach), which was probably stress related. 1 male had atrophy of the thymus, but this was not considered to be a direct compoundrelated effect and rather attributed to stress.
1500 ppm: changes observed in nasal passage (degeneration of olfactory epithelium, 4/10 males and 6/10 females, minimal to mild) and stomach; Olfactory epithelium was replace in some areas by transitional or respiratory epithelium.
500 ppm: no effects observed

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Description (incidence and severity):

No dose-related or statistically significant effect on epidydimidal or testicular sperm count was observed compared with controls, although the epididymidal sperm counts for all treated groups were lower than controls. Effects on testicular staging or spermatogenic were not evaluated due to the unacceptable condition of tissue.

Details on results:

Concentrations:
Nominal concentrations were generally 13-70 % higher than the analytical concentrations. The overall time-weighted average analytical concentrations of 548.4, 1487.5, and 3009.6 ppm for the male rats and 547.9, 1487.6, and 3008.8 ppm for the female rats were within 10 % of the target concentrations of 550, 1500, and 3000 ppm.

Effect levels

Key result

Dose descriptor:

NOEL

Effect level:

500 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical signs

food consumption and compound intake

histopathology: non-neoplastic

organ weights and organ / body weight ratios

Target system / organ toxicity

1

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

1 500 ppm

System:

central nervous system

Organ:

other: Not centered on a specific organ but general effects on neurological and behavioral functions as typically observed for alcohols (drowsiness and dizziness).

Treatment related:

yes

Dose response relationship:

yes

Relevant for humans:

yes

2

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

1 500 ppm

System:

respiratory system: upper respiratory tract

Organ:

nasal cavity

Treatment related:

yes

Dose response relationship:

yes

Relevant for humans:

no

Any other information on results incl. tables

Decreased body weight and feed consumption were noted for the 1500 and 3000 ppm groups, but there was no systemic or organ-specific toxicity. Degeneration of the olfactory epithelium at concentrations of 1500 and 3000 ppm was observed in areas of the nasal cavity that have demonstrated carboxylesterase activity (Bogdanffy, 1990: Biotransformation enzymes in the rodent nasal mucosa: the value of a histochemical approach. Environmental Health Perspectives 85, 177–186), but there was no evidence of pulmonary toxicity.