Registration Dossier

Administrative data

Endpoint:
two-generation reproductive toxicity
Remarks:
based on test type (migrated information)
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable documented publication

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Multigeneration study of 1,2,4-trichlorobenzene in rats
Author:
Robinson KS, Kavlock RJ, Chernoff N, and Gray LE
Year:
1981
Bibliographic source:
J Toxicol Environ Health 8: 489 - 500
Reference Type:
secondary source
Title:
European Union Risk Assessment Report - 1,2,4-Trichlorobenzene
Author:
European Commission - European Chemicals Bureau
Year:
2003
Bibliographic source:
Office for Official Publications of the European Communities

Materials and methods

Principles of method if other than guideline:
Rats were continously exposed to 0, 25, 100, or 400 ppm 1,2,4-trichlorobenzene in the drinking water, beginning with birth of the F0 generation and continuing through weaning of the F2 generation. Fertility, growth, viability, locomotor activity, blood chemical analysis, and histopathology analysis were performed
GLP compliance:
no
Remarks:
GLP was not mandatory at the time of the study
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Name of test material (as cited in study report): 1,2,4-trichlorobenzene
- Analytical purity: no data

Test animals

Species:
rat
Strain:
not specified
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratory, Wilmington, Mass, USA
- Age at study initiation: (P) 90-d-old; (F0) x 90-d-old; (F1) x 90-d-old
- Fasting period before study: no
- Housing: Upon arrival, 100 time-pregnant animals were housed individually in 43 X 23 X 20 cm plastic cages.
- Diet (e.g. ad libitum): Throughout the study, animals were fed commercial laboratory diet ad libitum.
- Water (e.g. ad libitum): The time-pregnant animals received tap water ad libitum until birth of F0 generation, when they were assigned to one of five treatment groups and given the appropriate water.



ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22-26 °C
- Photoperiod (hrs dark / hrs light): 12 h dark/ 12 h light)


Administration / exposure

Route of administration:
oral: drinking water
Vehicle:
other: the 1,2, 4-trichlorobenzene solutions contain 0.125% in drinking water.
Details on exposure:
Since 1,2,4-trichlorobenzene is not soluble in water at the concentrations used, the 1,2,4-trichlorobenzene solutions also contained a solubizer, Tween 20 at a concentraion of 0.125%.
Animals were given freshly prepared solutions at least twice weekley and allowed to drink ad libitum.
Details on mating procedure:
- M/F ratio per cage: In F0 and F1 generations 1M/2F.
- Length of cohabitation: 2 weeks
- After successful mating each pregnant female was caged (how): individually
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
Exposure period: from birth of F0 generation through weaning of F2 generation
Premating exposure period (males): F0: 90 days; F1: 90 days
Premating exposure period (females): F0: 90 days; F1: 90 days
Duration of test: until day 32 of F2 generation
Frequency of treatment:
continuously
Details on study schedule:

- Age at mating of the mated animals in the study: 90 days
Doses / concentrations
Remarks:
Doses / Concentrations:
25, 100 or 400 mg/l (see remark)
Basis:
nominal in water
No. of animals per sex per dose:
In all generations, each treatment group consisted in 17-23 litters.
Control animals:
other: yes, concurrent no treatment; yes, concurrent vehicle

Examinations

Statistics:
The significance of treatment-related effects was analyzed by analysis of variance and, when results were significant, by linear regression. Whenever a significant dose response was found by linear regression, Dunn´s procedure was used to determine the significance of pairwise comparisons. The organ weight and blood chemistry data in the F0 and F1 generations at day 95 were analyzed by regression procedure as 2 x 2 x 4 (sex, generation, dose) factorial design.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:
not examined
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
not examined
Other effects:
not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not examined
Reproductive performance:
no effects observed

Details on results (P0)

BODY WEIGHT AND DIETARY INTAKE (PARENTAL ANIMALS)
The postweaning growth of the F0 and F1 animals was not affected by 1,2,4-trichlorobenzene.
A treatment-related increase in food intake was found in the F0 males at day 29 (F [1,59]=4.97, p<0.028). There are also two instances of a treatment related decrease in water intake in the F0 generation, one in the females at day 35 (F [1,80]=5.71, p<0.018) and another in both sexes at day 83 [males, F [1,68]=11.72, p<0.001; females F [1,68]=15.05, p<0.001. In all three of these dietary effects in the F0 generation, Dunn´s procedure found only the high-dose group to be significantly different from controls. No treatment-related differenced in food or water intake was found in the F1 generation during the postweaning period.



ORGAN WEIGHTS (PARENTAL ANIMALS)
The 400 ppm 1,2,4-trichlorobenzene dose produced significantly increase enlarged adrenals in both sexes in the F0 and F1 animals at 95 d of age F [1,154]=7.68, p<0.006.

Effect levels (P0)

Dose descriptor:
NOAEL
Effect level:
ca. 25 mg/L drinking water

Results: F1 generation

General toxicity (F1)

Clinical signs:
not examined
Mortality / viability:
no mortality observed
Body weight and weight changes:
not examined
Sexual maturation:
no effects observed
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Histopathological findings:
not examined

Effect levels (F1)

Dose descriptor:
NOAEL
Generation:
F1
Effect level:
ca. 25 mg/L drinking water

Overall reproductive toxicity

Reproductive effects observed:
not specified

Any other information on results incl. tables

Table 1.Effects of 1, 2, 4-trichlorobenzene

 

Females delivering

 

Female bred

Litter size,day 1

Percent mortality today 12

Percent mortality from d12 to weaning

Dose (ppm1,2,4-trichlorobenzene)

F0

F1

F1

F2

F1

F2

F1

F2

0 (water)

23/24

18/24

13.3±0.94a

9.8±0.64

15.0±3.42

6.3±2.96

3.3±2.20

1.0±0.70

0 (tween20)

22/24

19/24

12.8 ±0.71

10.3±0.87

14.2±3.46

9.3±5.62

1.2±0.92

3.6±2.74

25

19/24

21/24

14.5± 0.42

10.5±0.98

21.3±5.02

3.7±2.50

2.0±0.97

0.8±0.62

100

18/24

17/24

13.4±0.80

12.8±0.88

21.8±6.77

5.7±2.19

3.2±1.63

1.2±0.60

400

22/24

20/24

14.1±0.36

12.8±0.78

13.1±4.00

5.4±2.33

4.3±2.47

3.0±1.34

dValuesare means ± SE

 

 

 

Table 2. Representative Dietary Intake data from the F0 Generation with Calculated Dosages

 

Dose (ppm1,2,4-trichlorobenzene

Female food intake (g/d per animal)

Female water intake (g/d per animal)

Calculated female dosage (mg/kg x day 1,2,4-trichlorobenzene)

Male food intake (g/d per animal)

Male water intake (mL/f per animal)

Calculated male dosage (mg/kg x day 1,2,4-trichlorobenzene)

29 days of age

0

13.9±0.4a

24.4±1.3

 

17.4±0.5

26.9±1.1

 

25

14.4±0.6

28.5±2.5

8.3±0.8

15.7±0.8

31.9±2.1

8.5±0.6

100

13.4±0.2

24.8±0.9

28.0±1.2

16.5±0.6

27.2±1.6

27.6±1.6

400

14.1±0.3

27.3±2.2

133.2±13.4

19.3±1.8b

32.1 ±3.4

133.6±15.6

83 days of age

0

20.0±0.7

31.6±1.6

 

31.7±0.8

43.9±1.8

 

25

20.0±0.7

31.6±1.3

3.7±0.1

30.6±1.0

47.0±2.2

2.5±0.1

100

20.0±0.8

30.8±1.7

14.8±1.0

30.9±1.2

42.0±1.3

8.9±0.3

400

19.6±0.8

26.2±0.8b

53.6±3.9

29.3±0.6

38.6±1.7b

33.0±1.4

aValues are means ± SE

bSignificantly different from control, p<0.05

 

 

 

Table 3. Locomotor Activity of Animals Exposed to 1,2,4-trichlorobenzene

 

 

 

 

Dose (ppm 1,2,4-trichlorobenzene)

Generation

Age (days)

Sex

0

25

100

400

F0

16

M

227±19.3a

246±19.6

184±30.7

207±16.9

 

 

F

292±44.2

233±36.2

202±35.7

253±34.3

F0

27

M

418±36.8

390±40.0

459±31.5

428±19.6

 

 

F

429±25.4

427±23.5

388±18.1

438±24.0

F0

48

M

620±42.7

744±46.9

633±62.5

633±59.5

 

 

F

701±37.7

778±86.7

772±38.5

811±61.4

F0

90

M

611±70.9

678±44.0

556±69.4

772±70.0

 

 

F

746±65.0

796±58.7

746±42.8

888±65.7

F1

31

M

555±49.3

510±40.7

500±59.3

472±48.7

 

 

F

467±63.2

556±40.7

462±51.3

578±48.7

F1

90

M

611±46.7

590±110.9

596±45.0

586±55.7

 

 

F

728±82.9

802±58.8

712±91.3

784±77.5

F2

26

M

394±30.8

373±28.5

282±14.6

387±41.4

 

 

F

286±44.2

359±88.5

344±58.1

373±70.0

 

Table 4.Effect of 1,2,4-trichlorobenzene in the drinking water on adrenal weights

 

 

 

Dose (ppm1,2,4-trichlorobenzene

Males

Females

F0, 95 days

0 (water)

28.7±1.78a

34.1±1.87

0 (tween20)

28.6±1.09

36.8±1.14

25

28.8±1.59

35.6±1.70

100

28.2±1.10

36.6±1.08

400

31.8±2.43b

41.5±1.99b

F1, 95 days

0 (water)

27.1±1.71

35.8±1.89

0 (tween20)

28.0±1.57

37.0±1.36

25

28.8±1.46

34.8±1.77

100

26.6±0.82

35.3±1.07

400

29.6±1.66b

38.5±1.89b

aValues are means ±SE; weights are in milligrams and for the left adrenal only-

bSignificantly different from controls, p<0.05

 

Applicant's summary and conclusion

Executive summary:

Robinson (1981):

Rats were continuously exposed to 0, 25, 100, or 400 ppm 1,2,4-trichlorobenzene in the drinking water, beginning with birth of F0 generation and continuing through weaning of the F2 generation. The treatment did not affect fertility, growth, viability, locomotor activity, or blood chemical analyses. Adrenal gland enlargement was observed in both the F0 generation and F1 animals at 95 d of age.