Hexachlorocyclopentadiene

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Reference 2

Reference Type:

publication

Title:

Toxicity of hexachlorocyclopentadiene: subchronic (13-week) administration by gavage to F344 rats and B6C3F1 mice.

Author:

Abdo KM, Montgomery CA, Kluwe WM, Farnell DR, Prejean JD.

Year:

1984

Bibliographic source:

J Appl Toxicol. 1984 Apr;4(2):75-81.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

Exposure 5 days per week. FOB and ophthalmological examination were not performed. Urinalysis, haematology, or clinical biochemistry were not examined

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Hexachlorocyclopentadiene

EC Number:

201-029-3

EC Name:

Hexachlorocyclopentadiene

Cas Number:

77-47-4

Molecular formula:

C5Cl6

IUPAC Name:

hexachlorocyclopentadiene

Test material form:

liquid

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratory
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 52 days
- Weight at study initiation: Females: 99 - 135 g. Males: 130 - 170 g.
- Housing: Five animals per cage in polycarbonate cages.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 20 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 72°F to 78°F (22°C to 25°C)
- Humidity (%): 23% to 58%
- Air changes (per hr): 15 changes per hour
- Photoperiod (hrs dark / hrs light): 12h/12h

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

VEHICLE
- Lot/batch no.: 1-13-82A
- Amount of vehicle (if gavage): 0.5ml/100g
- Purity: 100%

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Dosage analysis for concentration verification was performed in duplicate on each dose level for the first set of mixings and a set approximately midway through the study.

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

Once a day, 5 days per week. The frequency was selected to mimic the exposure of workers.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

10 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

19 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

38 mg/kg bw/day (nominal)

Doses / concentrations 5

Dose / conc.:

75 mg/kg bw/day (nominal)

Doses / concentrations 6

Dose / conc.:

150 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10 animals/sex/dose

Control animals:

yes, concurrent vehicle

Details on study design:

not specified

Positive control:

No

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: Initially, weekly, and at termination

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: Not specified

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: No

CLINICAL CHEMISTRY: No

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

IMMUNOLOGY: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes

HISTOPATHOLOGY: Yes

Statistics:

Not specified

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Animals treated at 150 mg/kg bw/day displayed a ruffled fur and a slight inactivity that were considered treatment-related. Other clinical observations were attributed to the housing of animals collectively or were not considered as significant due to their low incidence.

Mortality:

mortality observed, treatment-related

Description (incidence):

6/10 male rats receiving 150 mg/kg bw/day died as a result of the treatment. 1/10 female rats receiving 75 mg/kg bw/day died as a result of the treatment. Other deaths occurred in male and female rats at different doses that were attributed to improper gavage technique.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

A significant reduction of the bodyweight was observed in male rats receiving 38 mg/kg bw/day or above. A reduction was also observed in male rats receiving 10 and 19 mg/kg bw/day.
A significant reduction of the bodyweight was observed in female rats receiving 75 mg/kg bw/day or above. A reduction was also observed in male rats receiving 10, 19 and 75 mg/kg bw/day.

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

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

In male rats, the increase in relative liver weight at the dose levels of 10, 19, 38, and 75 mg/kg bw was -23% (decrease), 5%, 18%, and 31% respectively. The increase in relative kidney weight was -5% (decrease), 13%, 23% and 39% respectively.
In female rats, the increase in relative liver weight at the dose levels of 10, 19, 38, and 75 mg/kg bw was 17%, 4%, 19%, and 33% respectively. The increase in relative kidney weight was 10%, 12%, 30% and 62% respectively.
Relative organ weights could not be calculated at 150 mg/kg bw/day due to the deaths occurring at this dose level.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

In male rats receiving 75 mg/kg bw/day and above and female rats receiving 38 mg/kg bw/day and above, effects in stomach including mass and black areas were observed and considered treatment-related.
Other gross pathological findings were not considered significant or treatment-related.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Animals exposed to 38 mg/kg bw/day and above exhibited acute kidney tubular necrosis characterised by vacuolisation, cytomegaly, karyomegaly, anisokaryosis, and tubular dilation.
In male rats receiving 38 mg/kg bw/day or above and female rats receiving 19 mg/kg bw/day, significant proliferation and inflammatory changes of the epithelia in the stomach were observed.

Histopathological findings: neoplastic:

no effects observed

Details on results:

A NOAEL(systemic) of 10 mg/kg bw/day can be derived for both male and female rats.
A NOAEL(local) of 10 mg/kg bw/day can be derived for female rats.
A NOAEL(local) of 19 mg/kg bw/day can be derived for male rats.

Effect levels

1

Key result

Dose descriptor:

NOAEL

Remarks:

systemic

Effect level:

10 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical signs

gross pathology

histopathology: non-neoplastic

mortality

organ weights and organ / body weight ratios

2

Dose descriptor:

NOAEL

Remarks:

local

Effect level:

10 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Basis for effect level:

histopathology: non-neoplastic

3

Dose descriptor:

NOAEL

Remarks:

local

Effect level:

19 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

histopathology: non-neoplastic

Target system / organ toxicity

1

Critical effects observed:

yes

Lowest effective dose / conc.:

19 mg/kg bw/day (nominal)

System:

urinary

Organ:

kidney

Treatment related:

yes

Dose response relationship:

yes

Relevant for humans:

not specified

2

Critical effects observed:

yes

Lowest effective dose / conc.:

19 mg/kg bw/day (nominal)

System:

gastrointestinal tract

Organ:

stomach

Treatment related:

yes

Dose response relationship:

yes

Relevant for humans:

not specified

Applicant's summary and conclusion

Conclusions:

A subchronic toxicity study by the oral route was performed on rats using Hexachlorocyclopentadiene that allowed to determine a NOAEL(systemic) of 10 mg/kg bw/day for both male and female rats, a NOAEL(local) of 10 mg/kg bw/day for female rats, and a NOAEL(local) of 19 mg/kg bw/day for male rats.

Executive summary:

The repeated dose toxicity of Hexachlorocyclopentadiene by the oral route was evaluated using a method similar to the OECD Test Guideline 408 (non-GLP) with deviations.

Rats received doses of 0, 10, 19, 38, 75 and 150 of Hexachlorocyclopentadiene by gavage once a day, 5 days per week, for 13 weeks. The protocol was determined to mimic the exposure of workers. Mortality, clinical signs and body weight were recorded. At the end of the study, surviving animals were subjected to gross necropsy and histopathology.

Six male rats receiving 150 mg/kg bw/day and one female rats receiving 75 mg/kg bw/day died as a result of the treatment. Other deaths occurred that were attributed to improper gavage technique. Animals treated at 150 mg/kg bw/day displayed a ruffled fur and a slight inactivity that were considered treatment-related. Other clinical observations were attributed to the housing of animals collectively or were not considered as significant due to their low incidence.

A significant reduction of the bodyweight was observed in male rats receiving 38 mg/kg bw/day or above. A reduction was also observed in male rats receiving 10 and 19 mg/kg bw/day. A significant reduction of the bodyweight was observed in female rats receiving 75 mg/kg bw/day or above. A reduction was also observed in male rats receiving 10, 19 and 75 mg/kg bw/day.

In male rats, the increase in relative liver weight at the dose levels of 10, 19, 38, and 75 mg/kg bw was -23% (decrease), 5%, 18%, and 31% respectively. The increase in relative kidney weight was -5% (decrease), 13%, 23% and 39% respectively. In female rats, the increase in relative liver weight at the dose levels of 10, 19, 38 and 75 mg/kg bw was 17%, 4%, 19% and 33% respectively. The increase in relative kidney weight was 10%, 12%, 30% and 62% respectively.

In male rats receiving 75 mg/kg bw/day and above and female rats receiving 38 mg/kg bw/day and above, effects in stomach including mass and black areas were observed and considered treatment-related. Other gross pathological findings were not considered significant or treatment-related.

Animals exposed to 38 mg/kg bw/day and above exhibited acute kidney tubular necrosis characterised by vacuolisation, cytomegaly, karyomegaly, anisokaryosis, and tubular dilation. In male rats receiving 38 mg/kg bw/day or above and female rats receiving 19 mg/kg bw/day, significant proliferation and inflammatory changes of the epithelia in the stomach were observed.

This subchronic toxicity study by the oral route allowed to determine a NOAEL(systemic) of 10 mg/kg bw/day for both male and female rats, a NOAEL(local) of 10 mg/kg bw/day for female rats, and a NOAEL(local) of 19 mg/kg bw/day for male rats.