Captan

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Effects on fertility

Description of key information

Short description of key information:
Toxicity to fertility, three generation reproduction study, subacute study, oral (gavage), rat (COBS CD strain rats) m/f, in-house-method, NOEL: 500 mg/kg/bw/day

Link to relevant study records

Reference

Endpoint:

three-generation reproductive toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 July 1978 to 12 June 1980

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

no guideline followed

Principles of method if other than guideline:

In a three generation study, captan was administered in the diet to COBS CD strain rats at dosage levels of 0, 25, 100, 250 and 500 mg/kg bw/day (15 males and 30 females/dose group). The parental animals were dosed for approximately 100 days after which each F0 male was cohabited with two F0 females within the same treatment group. F0 rats were mated twice to produce two litters. Litters were reduced on day 4 to 10 pups per litter, of equal sex ratio if possible. Pups from the F1b litter (15 males and 30 females) were randomly selected from each dose group to produce F1 parental animals. F1 parental animals were administered test substance as described for the F0 parents and mated three times to produce F2a, F2b and F2c litters. Offspring from the F1 generations third mating (F2c) were delivered by caesarean section on day 19. Foetuses were examined for abnormalities. Pups from the F2b litters were selected to comprise the F2 generation parental animals and mated to produce the F3a and F3b litters. In each case, apart from the F2c offspring, two-thirds of the litters remaining at weaning (after selection for parental generations if applicable) were sacrificed and necropsied. Animals not selected for necropsy were sacrificed and discarded. Parameters evaluated were parental and pup behaviour, appearance and mortality (twice daily), parental body weight (weekly), litter weight (lactation day 1, 4, 7, 14), individual pup weight by sex (day 21), parental food consumption, reproductive parameters (male and female fertility, gestation period, litter size, sex ratio of litter, viability and survival of pups). Pups sacrificed and necropsied were examined for gross pathological abnormalities. In the teratology phase (F2c mating) the number and location of viable and non-viable foetuses, early/late resorptions, number of implantations and corpora lutea were recorded and foetuses were examined for abnormalities. Diet was analysed for the content and homogeneity of test substance.

GLP compliance:

yes

Limit test:

yes

Specific details on test material used for the study:

- Name of test material: Captan, N-(trichloromethylthio)cyclohex-4-ene-1,2-dicarboximide
- Molecular formula: C9H8Cl3NO2S
- Molecular mass: 300.59
- Physical state: white powder
- Analytical purity: 89% (w/w)
- Batch number: SX-944
- Date of arrival: 31. March 1978, 28. November 1978
- Storage conditions: room temperature

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on mating procedure:

1. First Generation (F1a Litter)
The control and treated rats were maintained on their respective diets throughout the duration of the F0 generation. After 102 days of test article exposure and at 133 days of age, the F0 parental rats were housed together in units of one male and two females within the same treatment group to produce the F1a litters. The rats were housed together for 15- consecutive days. Each female was examined daily until evidence of copulation was observed by means of vaginal smears for sperm or appearance of a vaginal copulatory plug. The day evidence of copulation was detected was designated gestation day 0. At the conclusion of the mating period, the females were individually housed in plastic cages containing ground corn-cob bedding and allowed to deliver. The day of parturition was designated lactation day 0. The number of viable and dead pups were recorded at lactation day 0. Survival of the pups at lactation days 1, 4, 7, 14 and 21 was recorded. Or lactation day 4, the litters were randomly reduced, using a table of random numbers, to 10 pups per litter, obtaining equal sex ratios if possible. Pups not selected were sacrificed and discarded. Total litter weights were determined on lactation days 1, 4 (before and after reduction), 7 and 14. At lactation day 21 (weaning), individual pup weights, by sex, were determined.2.
2. First Generation (F1b Litter)
After a minimun 10-day rest period following the F1a weaning, the F0 females were mated a second time to a different male within each treatment group to produce the F1b litters. The mating, gestation and lactation procedures employed for the F1a litters through weaning also applied to the F1b litters. After weaning, the F1b pups remained together as litters for seven days. Fifteen male and 30 female F1b pups were then randomly selected from each group to become the parents of the next generation (F1). Selection was made to minimize inbreeding during future matings. The F1b pups selected for the next generation were housed in individual suspended wire-mesh cages and administered the test diets of their parents.
3. Second Generation (F2a and F2b Litters)
The parental rats, selected from the F1b litters, remained on their respective control or treated diets during the span of this generation. At approximately 100 days of age, the F1 parental rats were mated as described for the mating to produce the F2a litters, with avoidance of sibling and cousin matings. The procedures described for the F1a gestation and lactation periods through necropsy were followed for the F2a. After the minimum 10-day rest period following weaning, the F1 parental rats were mated a second time to produce the F2b litters, again with avoidance of sibling and cousin matings. Procedures followed through gestation, lactation, selection of the next generation (F2) and the F2b pup necropsy were conducted in an identical manner to those followed during the same F1b periods. However, after weaning of the F2b litters, the F1 parental rats remained on study and were rested for a 10-day period prior to a third tsating (F2c).
4. Second Generation (F2c Litter)
Following the 10-day post-weaning rest period, the F1 parental rats were mated a third time (F2c) previously described lor the 1b mating, with avoidance of sibling and cousin matings. On gestation day 19, the F1 females were sacrificed and the F2c fetuses delivered by Cesarean section. If evidence of mating was not detected, those females were similarly sacrificed and examined as delivery appeared imminent or 25 days after separation from the male. Nongravid females were examined with emphasis placed on determining conditions which could have prevented pregnancy.
5. Third Generation (F3a and F3b Litters)
The F2 parental rats, selected from the F2b litters, remained on their respective control or treated diets until study temination. At approximately 100 days of age, the F2 parental rats were cated to produce the F3a litters as described F1a mating with avoidance of sibling and cousin matings. The procedures described for the F1a gestation and lactation periods through necropsy were followed for the F3a. After the mininimun 10-day post-weaning rest period, the F2 parental females were mated a second time with a different male within each treatment group to produce the F3b litters. The procedures followed during the mating, gestation and lactation periods were in a manner identical to those described for the F1b. As for all previous litters, two-thirds of each F3b litter were necropsied after weaning.

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

F0, F1, F2 parental animals were dosed for approximately 100 days

Frequency of treatment:

daily

Details on study schedule:

- F1 parental animals not mated until 100 days after selected from the F1 litters.- Age at mating of the mated animals in the study: 100 days

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

nominal in diet

Dose / conc.:

25 mg/kg bw/day (nominal)

Remarks:

nominal in diet

Dose / conc.:

100 mg/kg bw/day (nominal)

Remarks:

nominal in diet

Dose / conc.:

250 mg/kg bw/day (nominal)

Remarks:

nominal in diet

Dose / conc.:

500 mg/kg bw/day (nominal)

Remarks:

nominal in diet

No. of animals per sex per dose:

15 males and 30 females/dose group

Control animals:

yes, concurrent no treatment

Parental animals: Observations and examinations:

- parental behaviour- appearance and mortality (twice daily),
- parental body weight (weekly),
- parental food consumption,
- reproductive parameters (male and female fertility
- gestation period

Litter observations:

- pup behaviour- appearance and mortality (twice daily)
- litter weight (lactation day 1, 4, 7, 14),
- individual pup weight by sex (day 21),
- reproductive parameters (male and female fertility,
- gestation period,
- litter size,
- sex ratio of litter,
- viability and survival of pups)

Postmortem examinations (offspring):

- gross pathological abnormalities. In the teratology phase (F2c mating)
- the number and location of viable and non-viable foetuses,
- early/late resorptions,
- number of implantations and corpora lutea were recorded and foetuses were examined for abnormalities.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Dose-dependent decrease in male and female body weights in 100, 250 and 500 mg/kg bw/day treatment groups was observed
Statistically significant in 250 and 500 mg/kg bw/day treatment groups at all times and occasionally significant at 100 mg/kg/day

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Slight to moderate decreases in parental food consumption (g/food/rat/day) were observed in males and females

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Endocrine findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Key result

Dose descriptor:

NOEL

Remarks:

fertility toxicity

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive function (sperm measures)

Key result

Dose descriptor:

NOEL

Effect level:

25 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

mortality

Key result

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

- dose-dependent decrease in male and female body weights in 100, 250 and 500 mg/kg bw/day treatment groups was observed
- statistically significant in 250 and 500 mg/kg bw/day treatment groups at all times and occasionally significant at 100 mg/kg/day

Behaviour (functional findings):

no effects observed

Gross pathological findings:

no effects observed

Reproductive performance:

no effects observed

Description (incidence and severity):

No treatment-related or statistically significant differences were noted in male and female fertility, mean numbers of nonviable foetuses, early and late resorptions and postimplantation loss per dam or foetal sex distribution in any of the captan treated groups compared to the control. There were no biologically meaningful or statistically significant differences in the number of foetuses or litters with malformations in the captan treated groups compared to the control.

Key result

Dose descriptor:

NOEL

Effect level:

500 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive performance

Key result

Dose descriptor:

NOEL

Effect level:

25 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

mortality

Key result

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality / viability:

mortality observed, non-treatment-related

Description (incidence and severity):

During the second generation F1, deaths occurred in the 100 ng/kg/day treatment group (one female), the 250 mg/kg/day treatment group (one male) and the 500 mg/kg/day treatment group (two females).

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Male and female parental body weights in the 100, 250 and 500 mg/kg/day treatment groups were consistently decreased from the controls producing a dose-related trend. Statistical significance was noted at all points tested at the 250 and 500 mg/kg/day treatment levels.

Gross pathological findings:

no effects observed

Behaviour (functional findings):

no effects observed

Key result

Dose descriptor:

NOEL

Generation:

F1a

Effect level:

100 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

mortality

Key result

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality / viability:

mortality observed, non-treatment-related

Description (incidence and severity):

One F2 Parental female died in each of the control and 250 mg/kg/day treatment groups.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

- dose-related reductions in pup body weights were seen in all litters throughout lactation at 100, 250 and 500 mg/kg/day. These reductions werestatistically significant in all six matings in the 250 and 500 mg/kg/day dose groups throughout lactation to weaning and at most body weight intervals in the 100 mg/kg/day litters.

Gross pathological findings:

no effects observed

Behaviour (functional findings):

no effects observed

Key result

Dose descriptor:

NOEL

Generation:

F2

Effect level:

100 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

mortality

Key result

Critical effects observed:

no

Key result

Reproductive effects observed:

no

General observations: No treatment-related effects were seen in the general behaviour or appearance of the treated parental rats or pups. Survival of parental rats was unaffected by treatment.

Parental body weights: Diet analysis indicated that captan levels ranged from 90 to 100% of the nominal levels. Throughout all generations, a dose-dependent decrease in male and female body weights in 100, 250 and 500 mg/kg bw/day treatment groups was observed. This was statistically significant in 250 and 500 mg/kg bw/day treatment groups at all times and occasionally significant at 100 mg/kg/day. Although a reduction in the 25 mg/kg bw/day parental weight of males was evident during the F0 and F2 generations, there was no statistical significance. F2 generation male body weight at sexual maturity was similar to the control Parental food consumption: Slight to moderate decreases in parental food consumption (g food/rat/day) were observed in males and females of all treatment groups in all three generations ( Table 7.8.1 -1). Exceptions were slight increases over the control in 25 mg/kg bw/day F1 males and 100 mg/kg bw/day F2 females and similar food consumption in 25 mg/kg bw/day F2 females compared to the control.

Pup body weights: In general, dose-related reductions in pup body weights were seen in all litters throughout lactation at 100, 250 and 500 mg/kg/day. These reductions were statistically significant in all six matings in the 250 and 500 mg/kg/day dose groups throughout lactation to weaning and at most body weight intervals in the 100 mg/kg/day litters. The body weight of pups at lactation day 21 was significantly lower than the control in males and females. Mean pup body weights were slightly lower than the controls in the 25 mg/kg/day dose group with occasional statistical significance. At lactation day 21, mean pup body weights were slightly lower than the controls in all six matings with statistical significance noted for F1b litters only.

Foetal body weights: The mean foetal body weights in the 500 mg/kg bw/day dose group were significantly lower than the control (Table 7.8.1 -3).

Reproductive parameters: No consistent treatment-related effects on male and female fertility or length of gestation were observed. Two females at 500 mg/kg bw/day showed high incidences of peri-natal pup losses at the F1b mating, but as these were isolated incidences in this generation and were not seen in other matings or other generations, no association with treatment is made. Pup survival during lactation was unaffected in the 25 and 100 mg/kg bw/day dose groups. At 250 mg/kg bw/day a reduction in survival was noted through lactation day 4 of the F1a, F2a and F3a litters and in 500 mg/kg bw/day in the litters of all three generations ( Table 7.8.1 -2). Litter size was reduced in F1a and F1b litters in all treatment groups (except at 100 mg/kg bw/day for F1b) compared to the controls. The 250 and 500 mg/kg bw/day dose group F2a and F2b litter sizes were reduced compared to the controls.

Teratology: No treatment-related or statistically significant differences were noted in male and female fertility, mean numbers of nonviable foetuses, early and late resorptions and postimplantation loss per dam or foetal sex distribution in any of the captan treated groups compared to the control. There were no biologically meaningful or statistically significant differences in the number of foetuses or litters with malformations in the captan treated groups compared to the control.

Gross Pathology: There were no treatment-related abnormalities in any of the pups examined after weaning or in any of the parental rats that died during the study.

Conclusions:

The NOEL for maternal toxicity was 25 mg/kg bw/day and for fertility was 500 mg/kg bw/day in both males and females. The NOEL for pup survival was 100 mg/kg bw/day, based on reduced survival observed at 250 and 500 mg/kg bw/day. There were no indications of any cumulative effects of treatment in successive generations. It was not possible to establish NOELs for parental or pup toxicity, based on the reduction in body weight at the lowest dose tested (25 mg/kg bw/day). There was no evidence of teratogenicity at any dose.

Executive summary:

In a three generation reproduction study in Charles River COBS CD strain rats, Captan was administered in the diet at dosage levels of 0, 25, 100, 250 and 500 mg/kg/day. The first (F0) and third (F2) generations were mated twice and the second (F1) generation three times. Offspring from the second mating of the F0 and F2 generations were selected after weaning to comprise the next generations. Offspring from the generation's third mating (F2c) were delivered by Cesarean section on gestation day 19.

Throughout the duration of the study, the parental rats and pups were observed for signs of toxicity, changes in general behavior and appearance, and survival. Parental body weights and food consumption were recorded weekly. Litter and pup weights were recorded at specific intervals during lactation. Male and female fertility, length of gestation, pup viability and litter size were evaluated.

No changes considered to be related to Captan treatment were seen for the parental rats with respect, to general behavior and appearance, survival, male and female fertility or length of gestation.

 

Mean body weights of the parental females at the 25 mg/kg/day treatment level were comparable to the control during all generations.

Mean body weights of the 25 mg/kg/day parental males were slightly lower than the control during the F0 and F2 generations. The F2 generation male weights were reduced as a result of lower weight at initiation of the generation. At the 100, 250 and 500 mg/kg/day treatment levels, significant reductions in male and female body weights as compared to the control group were evident throughout all three generations following a dose-related trend. Food consumption values at all Captan levels were slightly to moderately decreased from the control values, paralleling the reduction observed in body weights.

The general behavior and appearance of the Captan treated pups were similar to the control. Pup survival during lactation at the 25 and 100 mg/kg/day treatment levels was not affected by treatment.

At the 250 mg/kg/day treatment level, decreased survival was noted through lactation day 4 of the F1a, F2a and F3a litters, while at the 500 mg/kg/day treatment level, consistent reductions were apparent in the litters of all three generations, primarily through lactation day 4.

Reduced litter sizes occurred in all Captan treatment groups in the first generation, and in the 250 and 500 mg/kg/day treatment groups F2a and F2b litters.

treatment-related reductions in mean pup body weights during lactation were evident in the litters of all three generations at the 100, 250 and 500 cg/kg/day treatment levels and most litters at the 25 mg/kg/day treatment level.

At Cesarean section of the F2c litters, no biologically meaningful or treatment-related differences in the mean numbers of nonviable fetuses, resorptions, postimplantation loss, fetuses or litters with malformations or fetal sex distribution were noted as compared co the control. A very slight reduction in the mean number of viable fetuses and total implantations was evident in the 250 and 500 mg/kg/day groups.

Mean numbers of corpora lutea at the 500 mg/kg/day treatment level was also decreased. The F2c fetal body weights were comparable to the control at Captan levels of 250 mg/kg/day or less. At 500 mg/kg/day, fetal body weights were significantly lower than the control.

At the gross necropsy examinations of the pups after weaning or of parental rats dying on study, no abnormality indicative of a compound related effect was observed.

From the results evaluated in the present study, doses of 25 mg/kg/day and above could not be considered no-effect levels.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

500 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Effects on developmental toxicity

Description of key information

Developmental Toxicity: Subacute (30 days) oral gavage, rabbit (f), NOEL (maternal and foetal) = 10 mg/kg/day, USEPA Guideline 83-3 equivalent to OECD 414 equivalent to EU 88/302/EEC, B31.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

5 March and 12 April 1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 83-3 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes

Limit test:

yes

Specific details on test material used for the study:

- Physical state: white powder
- Analytical purity: 91.2 % (w/w)
- Batch number: WRC 11240-37-1
- Storage conditions: in the dark, room temperature

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Interfauna UK, Huntingdon, Cambridgehire, UK.
- Weight at study initiation: 3.2-4.2 kg on the day of insemination (Day 1 of gestitaion)
- Housing: Individually in cages.
- Diet (e.g. ad libitum): CRB pellets supplied by Labsure Animal Diets, Lavender Mill, Manea, Cambridgehire UK.
- Water (e.g. ad libitum): Via an automatic watering system.
- Acclimation period: Yes, seven days prior to insemination.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 14-19 °C
- Humidity (%): 40-70%
- Air changes (per hr): 25-30 air changes per hour.
- Photoperiod (hrs dark / hrs light):12 hours light / 12 hours dark.

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Mixing appropriate amounts with (Type of food): Corn oil.
- Storage temperature of food: At room temperature.

IN-LIFE PHASE
- 5 March and 12 April 1990.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

A sample of each preparation owas analysed prior to the start of dising to verify the achieved concentrations of captan. The chemical stability of captan in corn oil was determined by re-analysis of the 10mg/kg formulation over a period of 45 days. The homogeneity of captan in corn oil was determined for the 10 and 100 mg/ml formulations.

Details on mating procedure:

Artificial Insemination Proven male New Zealand White rabbits previously obtained from Interfauna UK were used for this study. A total of 15 males was used for collection of semen. Semen was collected from each male using an artificial vagina. The volume of the sample obtained was measured and then diluted with sufficient physiological saline to inseminate one replicate. Approximately 1 ml of the diluted semen was inseminated into each female using a plastic catheter (18FG Nelaton supplied by Portex Limited, Hythe, Kent, UK). Each replicate of females was inseminated with semen from one male. After Insemination, each female was given an intravenous Injection of 25IU PROFASI 500 to promote ovulation. Eighty females were artificially inseminated for the study. The females were within a weight range of 3.2 -4.2 kg on the day of insemination (Day 1 of gestation).

Duration of treatment / exposure:

dosed once daily from days 7-19

Frequency of treatment:

dosed once daily

Duration of test:

30 days

No. of animals per sex per dose:

The study consisted of one control group and three treatment groups. Each contained twenty female rabbits:
Grroup 1: 20 female, Control: 0 mg/kg bw/day
Group 2: 20 female, 10 mg/kg bw/day
Group 3: 20 female, 30 mg/kg bw/day
Group 4: 20 female, 100 mg/kg bw/day

Control animals:

yes, concurrent vehicle

Maternal examinations:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: All animals were checked at lest once each day throughout the study.
- Details of changes in behaviour or clinical condition including no abnormalities detected were recorded daily during the study.

BODY WEIGHT: Yes
- Time schedule for examinations: The bodyweight of each animal was recorded on Days 1 and 4, 7-19 (inclusive) and on Days 22, 26 and 30 of gestation.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: The amount of food consumed by each animal was measured by giving a weighed quantity of food on Days 1, 4, 7, 10, 13, 16, 19, 22 and 26 and calculating the amount consumed from the residue on Days 4, 7, 10, 13, 16, 19, 22, 26 ad 30.

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 30.
- Organs examined: gravid uterus,

Ovaries and uterine content:

On day 30 females were sacrificed, examined macroscopically and the uteri examined for number of corpora lutea, live foetuses and intra uterine deaths. Foetuses were weighed, sexed and examined for external, visceral and skeletal abnormalities.
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: Individual foetal weights

Fetal examinations:

- External examinations: Yes, all foetuses
- Soft tissue examinations: Yes, all foetuses
- Skeletal examinations: Yes, all foetuses
- Head examinations: Yes, all foetuses

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

The incidence of few/no faeces on tray was increased in all captan treated groups compared with controls.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

There was a dose-related reduction in maternal body weight gain in 30 and 100 mg/kg bw/day dams, which was most marked during days 7 to 10. Compensatory body weight gain was evident during the post-dosing period in the 100 mg/kg bw/day dams.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

A dose-related reduction in food consumption was also seen in the 30 and 100 mg/kg bw/day females, followed by a compensatory increase in food consumption by 100 mg/kg bw/day dams, particularly on days 26 to 30. The low dose group was unaffected.

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Endocrine 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):

There was a dose-related reduction in maternal body weight gain in 30 and 100 mg/kg bw/day dams, which was most marked during days 7 to 10. Compensatory body weight gain was evident during the post-dosing period in the 100 mg/kg bw/day dams.

Gross pathological findings:

not examined

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Number of abortions:

effects observed, treatment-related

Description (incidence and severity):

One 100 mg/kg bw/day female was killed intercurrently following signs of abortion.

Pre- and post-implantation loss:

effects observed, treatment-related

Description (incidence and severity):

The incidence of pre-implantation loss in 100 mg/kg bw/day dams was not significantly affected. Post-implantation loss in 100 mg/kg bw/day dams was significantly increased compared to the control and reflected the increased incidences of intra-uterine deaths (early and late).

Total litter losses by resorption:

no effects observed

Description (incidence and severity):

Mean total implantation loss was not affected by captan treatment and as a result there was no adverse effect on the mean number of live foetuses compared to the controls.

Changes in pregnancy duration:

no effects observed

Changes in number of pregnant:

no effects observed

Key result

Dose descriptor:

NOEL

Effect level:

10 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

body weight and weight gain

Fetal body weight changes:

effects observed, treatment-related

Description (incidence and severity):

Mean foetal weight in the 100 mg/kg bw/day dose group was significantly lower than the control, with a consequent reduction (not statistically significant) in mean gravid uterine weight.

Reduction in number of live offspring:

no effects observed

Changes in litter size and weights:

effects observed, treatment-related

Description (incidence and severity):

Mean foetal weight in the 100 mg/kg bw/day dose group was significantly lower than the control, with a consequent reduction (not statistically significant) in mean gravid uterine weight.

Skeletal malformations:

no effects observed

Visceral malformations:

effects observed, treatment-related

Description (incidence and severity):

There was an increased incidence of foetuses with major defects of the head in both the 30 and 100 mg/kg bw/day groups

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects: yes.
Embryotoxic effect (100 mg/kg/day): increased post-implantation loss;
foetotoxic effect (100 mg/kg/day): reduced foetal weight.

Key result

Dose descriptor:

NOEL

Effect level:

10 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: fetotoxicity

Abnormalities:

not specified

Developmental effects observed:

not specified

Levels of captan in dosing solutions: Achieved concentrations of captan in dosing preparations were ± 4% of nominal levels. Homogeneity and stability of captan in solution were satisfactory.

General observations: Treated dams had an increased incidence of few or no faeces compared to the control. Increased incidences of diarrhoea in all treated groups and mucus in the faeces in 100 mg/kg bw/day dams were observed. One 100 mg/kg bw/day female was killed intercurrently following signs of abortion. There was a dose-related reduction in maternal body weight gain in 30 and 100 mg/kg bw/day dams, which was most marked during days 7 to 10. Compensatory body weight gain was evident during the post-dosing period in the 100 mg/kg bw/day dams (Table 7.8.2-2). A dose-related reduction in food consumption was also seen in the 30 and 100 mg/kg bw/day females, followed by a compensatory increase in food consumption by 100 mg/kg bw/day dams, particularly on days 26 to 30. The low dose group was unaffected.

 

Table 7.8.2-2 Developmental toxicity study in the rabbit: body weight of dams

Period (days)	Body weight gain (g) at dose (mg/kg bw/day)
	0	10	30	100
1 – 7	145.2	137.5	172.9	159.6
7 – 19	238.2	205.5	57.2*	-159.3**
7 – 10	15.6	40.2	-68.0*	-142.5**
10 – 13	85.9	52.5	68.8	11.2**
13 – 16	145.9	122.8	59.3*	23.0**
16 – 19	-9.3	-9.8	-2.9	-51.0
19 – 30	249.4	288.8	300.3	502.3**
19 – 22	31.1	53.1	51.4	150.4**
22 – 26	125.6	141.9	146.7	176.9
26 – 30	91.7	93.8	102.2	175.00**
1 – 30	632.7	631.8	530.4	502.6

Significantly different from the control, * (p < 0.05), ** (p < 0.01)

 

Pregnancy and litter data: There was no treatment-related effect on pregnancy rate. The incidence of pre-implantation loss in 100 mg/kg bw/day dams was not significantly affected. Post-implantation loss in 100 mg/kg bw/day dams was significantly increased compared to the control and reflected the increased incidences of intra-uterine deaths (early and late). Mean total implantation loss was not affected by captan treatment and as a result there was no adverse effect on the mean number of live foetuses compared to the controls. Mean foetal weight in the 100 mg/kg bw/day dose group was significantly lower than the control, with a consequent reduction (not statistically significant) in mean gravid uterine weight. A summary of litter data is given in Table 7.8.2-3.

 

Table 7.8.2-3. Developmental toxicity study in the rabbit: litter data

 

Litter data parameter	Dose (mg/kg bw/day)
	0	10	30	100
Corpora lutea (mean)	10.54	10.23	9.80	10.42
Pre-implantation loss (transformed mean)	0.490	0.428	0.369	0.291
Post-implantation loss (transformed mean)	0.311	0.337	0.325	0.485*
Implantations (mean)	8.46	8.23	8.50	0.50
Intra-uterine deaths (mean % early)	3.1	4.7	0.0	10.7
Intra-uterine deaths (mean % late)	3.5	4.2	9.5	11.9
Live foetuses (mean)	7.85	7.38	7.50	7.17
Mean gravid uterine weight (g)	514.8	481.2	472.7	440.3
Mean litter weight (g)	339.2	319.9	310.3	271.4
Mean foetal weight (g)	45.64	44.90	43.30	37.99**

Significantly different from the control, * (p < 0.05), ** (p < 0.01)

 

Foetal assessment (major defects): The incidence of foetuses with major defects was significantly increased in the 100 mg/kg bw/day dose group compared to the control. Eight foetuses from five litters had at least one major abnormality compared to one in the control. Four of the eight foetuses affected in the 100 mg/kg bw/day dose group were from one litter. There was no compound-related effect on the incidence of defects involving the cardiac blood vessels but there was an increased incidence of foetuses with major defects of the head in both the 30 and 100 mg/kg bw/day groups. In the latter group, two of the three affected foetuses were litter mates. Of the remaining types of major defects all but one occurred in the 100 mg/kg bw/day group. The possibility of the major defects being treatment-related cannot be dismissed though the small numbers involved and type of specific minor defects and the fact that several foetuses were litter mates, provides no strong evidence for a compound relationship.

Foetal assessment (minor defects): The incidence of minor external/visceral defects was increased in the 30 and 100 mg/kg bw/day dose groups compared to the control and was mainly due to an increase in the incidence of cysts on the liver. The overall incidence of minor skeletal defects was unaffected by treatment, although the incidence of unossified 6^thand 7^thlumbar transverse processes and asymmetric alignment of the pelvic girdle was increased in the 100 mg/kg bw/day dose group.

Foetal assessment (variants): There were no external or visceral variants. Each foetus had at least one skeletal variant. Treatment-related effects were seen in the incidence of the following variants in the 100 mg/kg bw/day dose group; odontoid partially ossified (increase); normal length extra 13th ribs (increase); 27 pre-sacral vertebrae (increase): asymmetric development of 1st and 2nd sacral vertebrae (increase); 4th, 5th, 6th and 7th lumbar transverse processes partially ossified; 2nd lumbar transverse processes partially ossified; 3^rdlumbar transverse processes fully ossified. The effects on ossification of the lumbar transverse processes reflect reduced ossification which may be associated with reduced foetal weight. The majority of these variants were also seen in the 30 mg/kg bw/day dose group.

The overall incidence of foetuses with extra 13th rib was increased in 30 and 100 mg/kg bw/day dose groups compared to the control (60.8, 52.1, 77.3 and 77.6% affected in the control, 10, 30 and 100 mg/kg bw/day dose groups).

Foetal assessment (manus and pes assessment): An increase in manus scores, reflecting the decrease in ossification was observed in the 100 mg/kg bw/day dose group (mean score 2.56, p <0.01) compared to the control (mean score 2.24). The mean pes score was 2.0 for all dose groups. A summary of the incidence of defects and variants is given in Table 7.8.2-4.

 

Table 7.8.2-4 Developmental toxicity study in the rabbit: summary of foetal defects and variants

 

Incidence of foetal defects and variants	Dose (mg/kg bw/day)
	0	10	30	100
Number of litters examined	13	13	10	12
External and visceral:
Number of foetuses examined	102	96	75	86
Number of foetuses with major defects	1	0	2	6*
Number of foetuses with minor defects only	1	3	6*	8**
Skeletal defects:
Number of foetuses examined	102	96	75	85
Number of foetuses with major defects	0	0	1	4*
Number of foetuses with minor defects only	37	41	25	36
Variants:
Number of foetuses examined	102	96	75	85
Number of foetuses showing variants	102	96	75	85

Significantly different from the control, * (p < 0.05), ** (p < 0.01)

 

Gross pathology dams: There was no evidence of treatment-related effects on the incidence of macroscopic findings

 

Conclusions:

The administration of captan at dose levels of 30 and 100 mg/kg bw/day was associated with maternal toxicity and retarded foetal development. Although increases in major defects at these dose levels provided no consistent evidence of a treatment-relationship due to the diverse nature of the abnormalities seen, an association with the administration of captan cannot be dismissed. The overall NOEL (maternal and foetal) was 10 mg/kg bw/day.

Executive summary:

The purpose of this study was to investigate the effects of captan on the embryonic and foetal development of the rabbit when administered by gavage during organogenesis.

The rabbit is one of the species generally recommended for assessment of teratogenicity and the New Zealand White strain was used because of its known susceptibility to a number of teratogens and because of the substantial background data within this laboratory relating to studies of this type. The oral route was chosen for administration of captan as this represents a possible route of human exposure.

Groups of 20 female New Zealand White rabbits were dosed by gavage with 0, 10, 30 or 100 mg captan/kg/day in corn oil from Days 7-19 (inclusive) of gestation which thus included the period of major organogenesis. A control group of animals received corn oil alone.

The day of insemination was designated Day 1 of gestation. On Day 30 of gestation the females were killed and their uteri examined for live foetuses and intra-uterine deaths. The foetuses were weighed, examined for external and visceral abnormalities, sexed, eviscerated and stained for skeletal examination.

Administration of captan at dose levels of 30 and 100 mg/kg/day was associated with maternal toxicity and developmental toxicity.

An increase in major defects at these dose levels provided no consistent evidence of a compound relationship due to the diverse nature of the abnormalties seen. The overall no-effect level was 10 mg captan/kg/day.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

10 mg/kg bw/day

Study duration:

subacute

Species:

rabbit

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Justification for classification or non-classification

No negative effects on reproduction and developmental toxicity were discovered. Captan is not classified as being toxic for reproduction.