1-chlorobutane

Endpoint summary

Description of key information

90 days oral NOAEL (rats) = 120 mg/kg bw/day (NTP, 1986)
90 days oral LOAEL (rats) = 250 mg/kg bw/day (NTP, 1986)
2-years oral NOAEL (rats)  = 60 mg/kg bw/day (NTP, 1986)

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March - June 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: comparable to guideline study with acceptable restrictions

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

only necropsy and histologic examination were performed, other observations (e.g. food consumption, haematology, clinical biology) are not regarded; administration five days per week

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: F344/N

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Portage, USA
- Age at study initiation: 7 weeks
- Weight at study initiation: males: 23 g; females: 18-19 g
- Housing: five per cage in polycarbonate cages (Lab Products, Rochelle Park, NJ, USA); Bedding: Aspen bed hardwood chips (American Exelsior Co., Baltimore,MD, USA) or Chips hardwood chips (Agway Inc., Syracuse, NY, USA)
- Diet: ad libitum Wayne Lab Blox pellets (Allied Mill, Chicago, IL; USA)
- Water: ad libitum (Automatic watering system; Edstrom Industries, Waterford, WI, USA)
- Acclimation period: 18 days


ENVIRONMENTAL CONDITIONS
- Temperature: mean 21.8 °C
- Humidity: 5% - 74% (average 40%)
- Air changes (per hr): 10
- Photoperiod: 12 hrs dark / 12 hrs light ( fluorescent light)


IN-LIFE DATES: March - July 1979

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Preparation were hand agitated for 10 sec and sealed in serum vials. Dose mixtures were stored at 4 °C for a maximum of 10 days.

VEHICLE
- Amount of vehicle (if gavage): 5 mL/kg bw/d

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Periodic analyses for n-butyl chloride in corn oil were performed by the testing and analytical chemistry laboratories. Duplicate 1 mL samples were extracted with methanol containing 2 mg/mL of n-amyl alcohol as an internal standard. Samples were analyzed by GC-FID. Individually spiked portions of undosed corn oil (5 or 6 concentrations bracketing the specified concentration range of the referee sample) were used to obtain standard data. The samples were determined from the linear regression equation computed from the standard data (peak area analysis).
Analyzed mixtures were within +/- 10% of the target concentration.

Duration of treatment / exposure:

13 weeks (90d)

Frequency of treatment:

5 d/w

Remarks:

Doses / Concentrations:
0, 30, 60, 120, 250 and 500 mg/kg bw/d
Basis:
actual ingested

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Doses selected for the 13-week studies were based on weight gain depression and clinical signs observed in the 14-days studies.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: two times per day

CLINICAL SIGNS
- Time schedule: recorded once per week

BODY WEIGHT: Yes
- Time schedule for examinations: once per week

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No

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: No

HAEMATOLOGY: No

CLINICAL CHEMISTRY: No

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes

HISTOPATHOLOGY: Yes

The following tissues were examined: gross lesions and tissue masses, mandibular lymph node, mammary gland, skin, salivary gland, sternebrae, thyroid gland, small intestine, colon, liver, prostate/testes or ovaries/uterus, lungs and bronchi, heart, esophagus, stomach, brain, thymus, trachea, pancreas, spleen, kidneys, adrenal glands, urinary bladder, pituitary gland, spinal cord (if neurologic signs present) and eyes (if grossly abnormal).

Tissues were preserved in 10% neutral buffered formalin, embedded in paraffin, sectioned and stained with hematoxylin and eosin.
After completion of the pathology examination, the slides, individual animal data records and summary tables were sent to an independent quality assurance laboratory for evaluation.

Statistics:

Data recording:
Data were recorded in the Cacinogenesis Bioassay Data System (Linhart et al., 1974). The data elements include the recommendations by the International Union Against Cancer (Berenblum, 1969)

Survival analyses:
The probability of survival was estimated by the product-limit procedure of Kaplan and Meier (1985) and is presented in the form of graphs. Statistical analyses for a possible dose-related effect on survival used the method of Cox (1972) for testing two groups for equality and Tarone's (1975) life table test for a dose-related trend. All reported P values for the survival analysis are two-sided.

Details on results:

CLINICAL SIGNS AND MORTALITY
6/10 males that received 500 mg/kg bw/d n-butyl chloride died before the end of the study, three of these because of gavage accidents.
Hyperactivity and convulsion on one or more occasions in male and female animals of the 250 and 500 mg/kg bw/d groups (250 mg/kg bw/d: 5/10 males and 2/10 females; 500 mg/kg bw/d: 9/10 males and 8/10 females). No animals of the lower dose group were hyperactive or convulsed.

BODY WEIGHT AND WEIGHT GAIN
The final mean body weights of males of the 250 and 500 mg/kg bw/d dose group were 11% or 20% lower than those of the vehicle control group. Females exposed to 250 and 500 mg/kg bw/d were 6% or 10% lower than that of the controls.

GROSS PATHOLOGY
Mild to moderate compound-related extramedullary hematopoiesis in the spleen in 3/10 males were observed that received 500 mg/kg bw/d. In two rats the severity was mild and in a third animal moderate. This lesion was not examined in the verhicle control group.

HISTOPATHOLOGY:
no histopathologic changes

Dose descriptor:

NOAEL

Effect level:

120 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Dose descriptor:

LOAEL

Effect level:

250 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: clinical signs; mortality; body weight;

Critical effects observed:

not specified

Body weights of rats in the thirteen-week gavage studies of n-butyl chloride

Dose (mg/kg bw/d)	Mean body weights (g)			Final weight relative to vehicle controls (%)
	initial^a	final	change^b
Males
0	131 +/- 2	299 +/- 4	+168 +/- 3	---
30	131 +/- 2	300 +/- 5	+169 +/- 5	100
60	130 +/- 2	290 +/- 4	+160 +/- 3	97
120	131 +/- 2	285 +/- 3	+154 +/- 4	95
250	131 +/- 2	265 +/- 4	+134 +/- 3	89
500	131 +/- 2	240 +/- 10	+113 +/- 9	80
Females
0	103 +/- 1	181 +/- 8	+78 +/- 6	---
30	102 +/- 1	177 +/- 3	+75 +/- 2	98
60	103 +/- 1	176 +/- 2	+73 +/- 1	97
120	103 +/- 2	174 +/- 1	+71 +/- 1	96
250	103 +/- 1	171 +/- 2	+68 +/- 2	94
500	103 +/- 1	163 +/- 2	+60 +/- 2	90

a: Initial means group body weights +/- standard error of the mean. Subsequent calculations are based on those animals surviving to the end of the study.

b: Mean body weight change of the survivors of the group +/- standard error of the mean. Final body weights were taken during week 12 of the study.

Endpoint conclusion

Dose descriptor:

NOAEL

60 mg/kg bw/day

Study duration:

chronic

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Data on subacute, subchronic and chronic 1-chlorobutane gavage studies are available from experiments with B6C3F1 mice and F344/N rats (NTP, 1986).

Male and female rats and mice (5 animals per sex per dose) were orally administered (gavage) at doses of 0, 190. 380, 750, 1500 and 3000 mg/kg bw/day 1-chlorobutane in corn oil for 14 consecutive days. No compound-related gross pathologic effects were observed in all groups. However compound-related deaths occurred in the groups administerd 3000 and 1500 mg/kg bw/day in mice and rats and in rats of the 750mg/kg bw/day group. The final mean body weight of male rats that received 750 mg/kg bw/day was lower (16%) than that of vehicle controls; no effect on body weight gain was observed in any other dose group. Hyperactivity and and convulsions following gavage administration and red discharge from the nose and mouth were observed in male rats that received 750 mg/kg bw/day and more. One female rat that received 1500 mg/kg bw/day had convulsions. Similar effects occurred in mice, although 1-chlorobutane appeared to be less toxic. No clinical biochemistry and haematology determinations as well as histopathological examinations were conducted. The NOAEL for 14 days repeated dose toxicity is considered to be 380 mg/kg/day for rats and 750 mg/kg/day for mice, respectively.

 

Subchronic studies were conducted with groups of 10 male and 10 female rats administered (gavage) 30, 60, 120, 250 and 500 mg/kg bw/day 1-chlorobutane 5 days per week for 90 days. Mice (10 animals per sex per dose) received 60, 120, 250, 500 and 1000 mg/kg bw/day 5 days per week for 13 weeks. Three of 10 male rats and one female mouse of the highest dose group died before the end of the studies. As in the 14-days studies, animals were hyperactive and convulsed on one or more occasions (2/10 female mice at 1000 mg/kg bw/day, 5/10 male and 2/10 female rats at 250 mg/kg bw/day and 9/10 male and 8/10 female rats at 500 mg/kg bw/day). No other compound-related clinical signs and no histopathological effects were observed in mice. In rats mild to moderate compound-related extramedullary hematopoiesis in the spleen was observed in 3/10 male rats receiving 500 mg/kg bw/day. The final mean body weights of male and female rats receiving 250 or 500 mg/kg bw/day were lower than those of the vehicle controls. Haematology and clinical biochemistry were not done.

The NOAEL for subchronic exposure to 1-chlorobutane was 120 mg/kg bw/day for rats and 500 mg/kg bw/day for mice.

 

In a carcinogenicity study rats and mice (50 animals per sex per dose) received (gavage) 0, 60 and 120 mg/kg bw/day and 0, 250, 500 and 1000 mg/kg bw/day 1-chlorobutane, respectively 5 days per week for 103 weeks. The survival relative to that of vehicle controls was significantly lower in high dose male (40/50 vs 17/50) and female (35/50 vs 11/50) rats at 120 mg/kg and in male mice receiving 1000 mg/kg bw/day (33/50 vs 10/50). Due to excessive mortality in the 1000 mg/kg bw/day female mice, the group was killed at week 45 and additional 2-year studies in mice of each sex were started at concentrations of 0 and 250 mg/kg bw/day 1-chlorobutane. Male mice in the 1000 mg/kg group had 10% lower mean body weights than the vehicle control group. No adverse effects on survival or body weights in other dosed groups of rats and mice were examined. Tremors and convulsions were observed on several occasions during the rat and mice studies primarily in the high dose groups (male rats: control 1/50, 60 mg/kg bw/day 3/50, 120 mg/kg bw/day 27/50; female rats: control 0/50, 60 mg/kg bw/day 7/50, 120 mg/kg bw/day 45/50; mice: in females of the 1000 mg/kg bw/day group terminated early and in 6/50 males at 1000 mg/kg bw/day). Hemorrhage of the brain and alveoli were examined in animals dying from convulsions. In addition, lymphoid depletion of the spleen and splenic hemosiderosis were observed in these high dose male and female rats.

The NOAEL for chronic exposure to 1-chlorobutane was 60 mg/kg bw/day for rats and 500 mg/kg bw/day for mice.

There are no dermal or inhalative repeated dose toxicity studies available.

Justification for classification or non-classification

The available data is conclusive but not sufficient for classification according to DSD (67/548/EEC) and CLP (1272/2008/EC).