Nickel(2+) propionate

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Effects on fertility

Description of key information

Read across to nickel sulfate hexahydrate CAS 10101-97-0 (similar to OECD 416, rat): no effects on fertility, NOAEL for maternal systemic effects was found to be 10 mg/kg bw/d

Link to relevant study records

Reference

Endpoint:

two-generation reproductive toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January 1999 to December 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

The highest dose level in this study, 10 mg/kg/day, did not result in toxicity of the parental animals.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, NY, USA
- Age at study initiation: 7 weeks
- Weight at study initiation: 205-257 g (males) and 147-213 g (females)
- Fasting period before study: not reported
- Housing: individually
- Use of restrainers for preventing ingestion (if dermal): yes/no
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 10 days

ENVIRONMENTAL CONDITIONS
- Temperature: 18-26 °C
- Humidity (%): 30-70%
- Air changes (per hr): 10-15 per hour
- Photoperiod (hrs dark / hrs light): 12-h light/dark photoperiod.

IN-LIFE DATES: From: February 1, 1999 To: October 15, 1999

Route of administration:

oral: gavage

Vehicle:

other: deionized water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test substance was dissolved in reverse osmosis deionized water. Control animals received appropriate volumes of water only. The homogeneity and stability of the test substance in dosing solutions were determined. The concentration of the test substance in dosing solutions was analytically confirmed at different time intervals during the study period. Groups of 56 test animals of each parental group (28 males/28 females) received the test substance daily by gavage at the following dosage concentrations: 0, 0.1, 0.25, 0.50, and 1.00 mg/ml (equivalent to dose levels of 0, 1.0, 2.5, 5.0, and 10.0 mg/kg/day). Dose volume was 10 ml/kg, adjusted for body weight. F0 parents and F1 pups selected as the parental group for the F2 generation received the test substance daily by gavage. F0 parental animals received the test substance (or vehicle for control group) daily for 10 weeks, starting 70 days prior to mating. F1 offspring selected to produce the F2 generation received the test substance starting on postpartum day 22 and dosing continued until one day prior to sacrifice.

VEHICLE
- deionized water

Details on mating procedure:

- M/F ratio per cage: Animals were caged as mating pairs (1:1) until copulation was confirmed, then transferred to individual cages.
- Proof of pregnancy: The presence of a vaginal plug or sperm was designated as day 0 of gestation.
Estrous cycle determinations (length and normality) were made daily prior to mating and during cohabitation.
- Dams and pups were caged together during lactation.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

analyzed by AAS

Duration of treatment / exposure:

Exposure period: F0: before and during mating, pregnancy, and through weaning of F1 offspring. F1: after weaning, during growth, mating, production and weaning of F2 offspring
Premating exposure period (males): 70 days
Premating exposure period (females): 70 days
Duration of test: 2 generations

Frequency of treatment:

daily

Details on study schedule:

- F1 parental animals not mated until 70 days after selected from the F1 litters.

Dose / conc.:

0 mg/kg bw/day (nominal)

Dose / conc.:

1 mg/kg bw/day (nominal)

Dose / conc.:

2.5 mg/kg bw/day (nominal)

Dose / conc.:

5 mg/kg bw/day (nominal)

Dose / conc.:

10 mg/kg bw/day (nominal)

No. of animals per sex per dose:

28

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Based on the results of 1 generation study, the doses of 0, 1, 2.5, 5.0, and 10 mg/kg-day were selected
- Rationale for animal assignment: random

Positive control:

none reported

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: more detailed clinical observations were made weekly. During gestation and lactation, F0 and F1 females were examined daily for clinical signs of toxicity

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION: Yes
- Time schedule for examinations: weekly

Oestrous cyclicity (parental animals):

Daily vaginal smears were collected for a minimum of 3 weeks prior to mating.

Sperm parameters (parental animals):

Parameters examined in F0 and F1 parental males [sperm count, concentration, motility, and morphology)

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- If yes, maximum of 8 pups/litter (4/sex/litter as nearly as possible); excess pups were killed and discarded.

PARAMETERS EXAMINED
The following parameters were recorded for each pup during lactation: viability, external examinations, sex determinations, and body weights. F1 and F2 litters were randomly adjusted to 4 males and 4 males on lactation day 4. F1 pups used as the parental animals for the F2 generation were selected between postpartum days 4 and 21. A total of 28 male and 28 female F1 pups were selected. The remaining F1 pups and F2 pups were sacrificed and gross necropsy examinations were performed. Surviving F0 and F1 parental animals were sacrificed and an assessment was made of reproductive performance.

Postmortem examinations (parental animals):

HISTOPATHOLOGY / ORGAN WEIGHTS:
The following organs from surviving F0 and F1 parental animals were preserved for histopathological examination: adrenal glands, brain, gross lesions, kidneys, liver, ovaries, pituitary, prostate, right epididymis, testes, seminal vesicles, spleen, uterus, and vagina. The following organs from surviving F0 and F1 parental animals were weighed and recorded: adrenal glands, brain, epididymides, kidneys, testes, ovaries, pituitary, prostate, seminal vesicles, spleen, and uterus.

Postmortem examinations (offspring):

HISTOPATHOLOGY / ORGAN WEIGHTS:
The following organs from surviving F1 parental animals were preserved for histopathological examination: adrenal glands, brain, gross lesions, kidneys, liver, ovaries, pituitary, prostate, right epididymis, testes, seminal vesicles, spleen, uterus, and vagina. The following organs from surviving F0 and F1 parental animals were weighed and recorded: adrenal glands, brain, epididymides, kidneys, testes, ovaries, pituitary, prostate, seminal vesicles, spleen, and uterus.

Statistics:

One-way analysis of variance (ANOVA) was used to analyze parental and pup body weight, body weight gain, food consumption, organ weights, length of gestation and estrous cycle, and litter size. If significance was detected, Dunnett's test was performed to compare control and treatment groups. Copulation and fertility indices, pup sex ratios, numbers of live and dead pups, and pup survival were evaluated by Chi-Square test. Post-implantation loss was evaluated using the Mann-Whitney U test. The level of significance was 5% (p<0.05).

Reproductive indices:

Copulation and fertility indices, pup sex ratios, numbers of live and dead pups, and pup survival

Offspring viability indices:

Copulation and fertility indices, pup sex ratios, numbers of live and dead pups, and pup survival

Clinical signs:

no effects observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

not examined

Other effects:

no effects observed

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS):
F0 generation: No test substance related mortality of clinical signs of toxicity.

ALL PARAMETERS:
There were no toxicologically meaningful differences in body weight gain or food consumption, copulation and fertility indices, gestation length, implantation and post-implantation loss, or sperm parameters. The numbers of live pups of treated female on lactation day 0 were not significantly different from that control group. Post-implantation loss was higher at 10 mg/kg/day (2.1), but was not statistically different from the control group (0.9). No treatment related changes found at gross necropsy. Statistically significant differences in organ weights included decreased absolute and relative livers weights in males at 10 mg/kg/day, decreased absolute brain weight in females at 2.5 mg/kg/day, and increased relative liver weight in females at 1.0, 2.5, and 10.0 mg/kg/day.

Key result

Dose descriptor:

NOAEL

Effect level:

10 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: absence of any effects on fertility

Remarks on result:

other: equivalent to 2.2 mg Ni/ kg bw

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

F1 generation: There were no toxicologically meaningful differences in pup viability data or pup body weights during lactation. Mean litter size on lactation day 0 ranged from 13.6 pups/litter (1.0 mg/kg/day group) to 11.4 pups per litter (10 mg/kg/day group). Post-implantation loss was slightly higher at 10 mg/kg/day (1.2), but was not statistically different from the control group (0.9). Clinical signs were noted during lactation, but were not considered to be test-substance related. Clinical signs were of low incidence and sporadically distributed among treatment groups. Vaginal opening and completion of preputial separation differences were not considered to be treatment related. Vaginal opening of control and 10 mg/kg/day pups occurred by postpartum day 35. Preputial separation of control and male pups in the 10 mg/kg/day group was completed by postpartum day 46. Gross necropsy observations included atelectasis and absence of milk in the stomach. Other necropsy findings were of low incidence and sporadically distributed among treatment groups.

Of F1 animals selected to produce the F2 generation, no test substance related mortality of clinical signs of toxicity were noted. Clinical signs were of low incidence and sporadically distributed among treatment groups and were, therefore, not considered test substance related. There were no toxicologically meaningful differences in body weight or body weight gains during the growth phase, however, mean body weight gain was significantly lower in the 1.0 and 5.0 mg/kg/day treatment groups during lactation days 14-21. There were no toxicologically meaningful differences in food consumption. No statistically significant differences were found in copulation or fertility indices, estrous cycle determinations, precoital intervals, or gestation lengths. There were no statistically significant differences in mean implantation scar counts, mean number of live pups on lactation day 0, or mean post-implantation loss. Statistically significant differences in organ weights included decreased absolute pituitary weight in 1.0 mg/kg/day males, increased relative adrenal weight and decreased relative liver weight in 5.0 and 10.0 mg/kg/day males, and decreased relative liver weight in 2.5 and 10.0 mg/kg/day females. There were no toxicologically meaningful differences in sperm parameters of 10 mg/kg/day males. No test substance related microscopic histopathological changes were noted. However, the unequivocal NOEAL of 5 mg/kg/day will be used for regulatory purposes.

F2 generation: No test substance related clinical signs of toxicity were noted. There were no statistically significant differences in body weights during lactation. Gross necropsy observations included atelectasis and absence of milk in the stomach. Other necropsy findings were of low incidence and sporadically distributed among treatment groups.

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

5 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

viability

Key result

Reproductive effects observed:

no

Oral (gavage) administration at dose levels up to 10 mg/kg/day (2.2 mg Ni/kg) had no effect on F0 orF1 survival, growth, mating behavior, fertility, gestation, parturition, or lactation. There was no test substance related mortality or clinical signs of toxicity in F0 and F1 rats or their offspring. Pup viability and growth was not affected. There were no toxicologically meaningful differences in estrous cycling, sperm parameters, copulation, and fertility indices, precoital intervals, gestation lengths, gross necropsy findings, or the onset of sexual maturation in F1 rats. Histopathological examinations did not reveal any test article-related changes in the liver, reproductive organs, or other tissues examined. Statistically significant reductions in absolute and/or relative liver weights in F0 males at 10 mg/kg/day and in F1 males at 5.0 and 10.0 mg/kg/day were not regarded as toxicologically significant. Relative liver weight values were less than 10% different  from the respective control values. 

Conclusions:

10 mg/kg/day is considered a No-Observed-Adverse-Effect Level (NOAEL) for oral administration of the test substance over two generations in rats.

Executive summary:

 

 

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

10 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

study conducted similar to OECD Guideline, well documented publication

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

One-generation reproductive toxicity study

In a study conducted equivalent or similar to OECD Guideline 415, the substance Nickel sulphate hexahydrate (CAS 10101-97-0) was administered orally (gavage) daily to 8 rats/sex/dose from 14 days prior to mating until postnatal day 21 (day 21 of lactation). The nominal test concentrations were 0, 10, 20, 30, 50 and 75 mg/kg bw/d. As a result, no effects were observed regarding the parameters clinical signs, body weight and weight changes, food consumption, organ weights or organ/body weight ratios. No effects concerning copulation and fertility indices, gestation length, implantation and post-implantation loss, or sperm parameters were detected either. No treatment related changes found at gross necropsy. However, post-implantation loss was significantly higher at 30, 50 and 75 mg/kg bw/d. Concerning the F1 generation litter size was significantly decreased at 10, 20, 30, and 75 mg/kg bw/d. No significant differences in clinical signs, pup weights, weight gain, or gross necropsy findings were observed. This study served as range-finding study for the definiute OECD 416 study, and based on the results the following dose levels were selected: .0, 2.5, 5 and 10 mg/kg bw/d.

Two-generation reproductive toxicity study

The study was conducted similar to OECD Guideline 416 with with rats. The animals were caged as mating pairs (1:1) until copulation was confirmed, then transferred to individual cages. Estrous cycle determinations (length and normality) were made daily prior to mating and during cohabitation. The presence of a vaginal plug or sperm was designated as day 0 of gestation. Dams and pups were caged together during lactation. The test substance was dissolved in reverse osmosis deionized water. Control animals received appropriate volumes of water only. Groups of 56 test animals of each parental group (28 males/28  females) received the test substance daily by gavage at the following concentrations:  0, 0.1, 0.25, 0.50, and 1.00 mg/mL (equivalent to dose levels of 0, 1.0, 2.5, 5.0, and 10.0 mg/kg bw/day). The dose volume was 10 mL/kg, adjusted for body weight.  F0 parents and F1 pups selected as the parental group for the F2 generation received the test substance daily by gavage. F0 parental animals were dosed daily for 10 weeks, starting 70 days prior to mating.  F1 offspring selected to produce the F2 generation received the test substance starting on postpartum day 22 and dosing continued until one day prior to sacrifice. General health checks of F0 and F1 parental animals were made twice daily, and more detailed clinical observations were made weekly. During gestation and lactation, F0 and F1 females were examined daily for clinical signs of toxicity. Individual body weights were measured weekly in F0 and F1 parental animals. Mated females and females that delivered were weighed on days 0, 7, 14, and 20 during gestation, and on days 1, 4, 7, 14, and 21 during lactation. Food consumption was recorded weekly, except during cohabitation and lactation. The following parameters were recorded for each pup during lactation: viability, external examinations, sex determinations, and body weights.  F1 and F2 litters were randomly adjusted to 4 males and 4 males on lactation day 4.

F1 pups used as the parental animals for the F2 generation were selected between postpartum days 4 and 21. A total of 28 male and 28 female F1 pups were selected.  The remaining F1 pups and F2 pups were sacrificed and gross necropsy examinations were performed.  Surviving F0 and F1 parental animals were sacrificed and an assessment was made of reproductive performance.  The following organs from surviving F0 and F1 parental animals were preserved for histopathological examination:  adrenal glands, brain, gross lesions, kidneys, liver, ovaries, pituitary, prostate, right epididymis, testes, seminal vesicles, spleen, uterus, and vagina.  The following organs from surviving F0 and F1 parental animals were weighed and recorded:  adrenal glands, brain, epididymides, kidneys, testes, ovaries, pituitary, prostate, seminal vesicles, spleen, and uterus. Sperm was collected from F0 and F1 parental males and examined for sperm count, concentration, motility, and morphology.

Results F0 generation:

No test substance related mortality of clinical signs of toxicity.  There were no toxicologically meaningful differences in body weight gain or food consumption, copulation and fertility indices, gestation length, implantation and post-implantation loss, or sperm parameters. The numbers of live pups of treated female on lactation day 0 were not significantly different from that control group.  Post-implantation loss was higher at 10 mg/kg bw/day (2.1), but was not statistically different from the control group (0.9). No treatment related changes found at gross necropsy.  Statistically significant differences in organ weights included decreased absolute and relative livers weights in males at 10 mg/kg bw/day, decreased absolute brain weight in females at 2.5 mg/kg bw/day, and increased relative liver weight in females at 1.0, 2.5, and 10.0 mg/kg bw/day.

Results F1 generation:

There were no toxicologically meaningful differences in pup viability data or pup body weights during lactation. Mean litter size on lactation day 0 ranged from 13.6 pups/litter (1.0 mg/kg bw/day group) to 11.4 pups per litter (10 mg/kg bw/day group).  Post-implantation loss was slightly higher at 10 mg/kg bw/day (1.2), but was not statistically different from the control group (0.9). Clinical signs were noted during lactation, but were not considered to be test-substance related.  Clinical signs were of low incidence and sporadically distributed among treatment groups. Vaginal opening and completion of preputial separation differences were not considered to be treatment related. Vaginal opening of control and 10 mg/kg bw/day pups occurred by postpartum day 35.  Preputial separation of control and male pups in the 10 mg/kg bw/day group was completed by postpartum day 46.  Gross necropsy observations included atelectasis and absence of milk in the stomach. Other necropsy findings were of low incidence and sporadically  distributed among treatment groups. Of F1 animals selected to produce the F2 generation, no test substance related mortality of clinical signs of toxicity were noted. Clinical signs were of low incidence and sporadically distributed among treatment groups and were, therefore, not considered test substance related. There were no toxicologically meaningful differences in body weight or body weight gains during the growth phase, however, mean body weight gain was significantly lower in the 1.0 and 5.0 mg/kg bw/day treatment groups during lactation days 14-21.  There were no toxicologically meaningful differences in food consumption. No statistically significant differences were found in copulation or fertility indices, estrous cycle determinations, precoital intervals, or gestation lengths. There were no statistically significant differences in mean implantation scar counts, mean number of live pups on lactation day 0, or mean post-implantation loss. Statistically significant differences in organ weights included decreased absolute pituitary weight in 1.0 mg/kg bw/day males, increased relative adrenal weight and decreased relative liver weight in 5.0 and 10.0 mg/kg bw/day males, and decreased relative liver weight in 2.5 and 10.0 mg/kg bw/day females. There were no toxicologically meaningful differences in sperm parameters of 10 mg/kg bw/day males. No test substance related microscopic histopathological changes were noted.

Results F2 generation:

No test substance related clinical signs of toxicity were noted.  There were no statistically significant differences in body weights during lactation. Gross necropsy observations included atelectasis and absence of milk in the stomach. Other necropsy findings were of low incidence and sporadically distributed among treatment groups.

The study was conducted to evaluate the potential effects of the test substance administered to Sprague-Dawley rats in a two-generation study. Oral (gavage) administration of the test substance at dose levels up to 10 mg/kg bw/day (2.2 mg Ni/kg) had no effect on F0 or F1 survival, growth, mating behavior, fertility, gestation, parturition, or lactation.  There was no test substance related mortality or clinical signs of toxicity in F0 and F1 rats or their offspring.  Pup viability and growth was not affected. There were no toxicologically meaningful differences in estrous cycling, sperm parameters, copulation, and fertility indices, precoital intervals, gestation lengths, gross necropsy findings, or the onset of sexual maturation in F1 rats.  Histopathological examinations did not reveal any test article-related changes in the liver, reproductive organs, or other tissues examined.  Statistically significant reductions in absolute and/or relative liver weights in F0 males at 10 mg/kg bw/day and in F1 males at 5.0 and 10.0 mg/kg bw/day were not regarded as toxicologically significant. Relative liver weight values were less than 10% different from the respective control values.  

Based on the study results the NOAEL for maternal effects was determined to be 10 mg/kg bw/d.

 

Effects on developmental toxicity

Description of key information

Read across to nickel sulfate hexahydrate (CAS 10101-97-0) (similar to OECD 416, rat): NOAEL for maternal systemic effects was found to be 10 mg/kg bw/d, NOAEL for teratogenicity was determined to be 5 mg/kg bw/d

Read across to nickel chloride hexahydrate (CAS 7791-20-0), mouse: teratogenic effects observed, NOAEL for maternal toxicity as well as developmental effects was determined to be 92.25 mg Ni/kg bw/d.

Link to relevant study records

Reference

Reference 1

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

August 1998 to December 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

The highest dose level in this study, 10 mg/kg/day, did not result in toxicity of the parental animals.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, NY, USA
- Age at study initiation: 7 weeks
- Weight at study initiation: 205-257 g (males) and 147-213 (females)
- Fasting period before study: not reported
- Housing: individually
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 10 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-26 °C
- Humidity (%): 30-70%
- Air changes (per hr): 10-15 per hour
- Photoperiod (hrs dark / hrs light): 12-h light/dark photoperiod

IN-LIFE DATES: From: February 1, 1999 To: October 15, 1999

Route of administration:

oral: gavage

Vehicle:

other: deionized water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test substance was dissolved in reverse osmosis deionized water. Control animals received appropriate volumes of water only. The homogeneity and stability of the test substance in dosing solutions were determined. The concentration of the test substance in dosing solutions was analytically confirmed at different time intervals during the study period. Groups of 56 test animals of each parental group (28 males/28 females) received the test substance daily by gavage at the following dosage concentrations: 0, 0.1, 0.25, 0.50, and 1.00 mg/ml (equivalent to dose levels of 0, 1.0, 2.5, 5.0, and 10.0 mg/kg/day). Dose volume was 10 mL/kg, adjusted for body weight. F0 parents and F1 pups selected as the parental group for the F2 generation received the test substance daily by gavage. F0 parental animals received the test substance (or vehicle for control group) daily for 10 weeks, starting 70 days prior to mating. F1 offspring selected to produce the F2 generation received the test substance starting on postpartum day 22 and dosing continued until one day prior to sacrifice.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyzed by AAS

Details on mating procedure:

M/F ratio per cage: Animals were caged as mating pairs (1:1) until copulation was confirmed, then transferred to individual cages.
- Proof of pregnancy: The presence of a vaginal plug or sperm was designated as day 0 of gestation.
-Estrous cycle determinations (length and normality) were made daily prior to mating and during cohabitation.
-Dams and pups were caged together during lactation.

Duration of treatment / exposure:

Exposure period: F0: before and during mating, pregnancy, and through weaning of F1 offspring. F1: after weaning, during growth, mating, production and weaning of F2 offspring
Premating exposure period (males): 70 days
Premating exposure period (females): 70 days
Duration of test: 2 generations

Frequency of treatment:

daily

Duration of test:

two generations

Dose / conc.:

10 mg/kg bw/day (nominal)

Dose / conc.:

0 mg/kg bw/day (nominal)

Dose / conc.:

1 mg/kg bw/day (nominal)

Dose / conc.:

2.5 mg/kg bw/day (nominal)

Dose / conc.:

5 mg/kg bw/day (nominal)

No. of animals per sex per dose:

28

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly
- During gestation and lactation, F0 and F1 females were examined daily for clinical signs of toxicity.

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE: Yes
- Time schedule for examinations: weekly

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
- Gravid uterus weight: Yes
- Number of implantation scar counts: Yes
- Number of live pups on lactation day 0
- Number of post-implantation losses: Yes
- Number of early resorptions: No data

Fetal examinations:

- External examinations: Yes
- Soft tissue examinations: Yes

Statistics:

One-way analysis of variance (ANOVA) was used to analyze parental and pup body weight, body weight gain, food consumption, organ weights, length of gestation and estrous cycle, and litter size. If significance was detected, Dunnett's test was performed to compare control and treatment groups. Copulation and fertility indices, pup sex ratios, numbers of live and dead pups, and pup survival were evaluated by Chi-Square test.
Post-implantation loss was evaluated using the Mann-Whitney U test. The level of significance was 5% (p<0.05).

Indices:

F0 and F1 Reproduction Indices: There were no statistically significant or toxicologically meaningful differences in F0 copulation and fertility indices, estrous cyclicity, precoital intervals, or gestation lengths.

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS):
F0 generation: No test substance related mortality of clinical signs of toxicity.

ALL PARAMETERS:
There were no toxicologically meaningful differences in body weight gain or food consumption, copulation and fertility indices, gestation length, implantation and post-implantation loss, or sperm parameters. The numbers of live pups of treated female on lactation day 0 were not significantly different from that control group. Post-implantation loss was higher at 10 mg/kg/day (2.1), but was not statistically different from the control group (0.9). No treatment related changes found at gross necropsy. Statistically significant differences in organ weights included decreased absolute and relative livers weights in males at 10 mg/kg bw/day, decreased absolute brain weight in females at 2.5 mg/kg bw/day, and increased relative liver weight in females at 1.0, 2.5, and 10.0 mg/kg bw/day.

Key result

Dose descriptor:

NOAEL

Effect level:

10 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: absence of effects

Remarks on result:

other: equivalent to 2.2 mg Ni/ kg bw

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects: no effects

Details on embryotoxic / teratogenic effects:
F1 generation: There were no toxicologically meaningful differences in pup viability data or pup body weights during lactation. Mean litter size on lactation day 0 ranged from 13.6 pups/litter (1.0 mg/kg bw/day group) to 11.4 pups per litter (10 mg/kg bw/day group). Post-implantation loss was slightly higher at 10 mg/kg bw/day (1.2), but was not statistically different from the control group (0.9). Clinical signs were noted during lactation, but were not considered to be test-substance related. Clinical signs were of low incidence and sporadically distributed among treatment groups. Vaginal opening and completion of preputial separation differences were not considered to be treatment related. Vaginal opening of control and 10 mg/kg bw/day pups occurred by postpartum day 35. Preputial separation of control and male pups in the 10 mg/kg bw/day group was completed by postpartum day 46. Gross necropsy observations included atelectasis and absence of milk in the stomach. Other necropsy findings were of low incidence and sporadically distributed among treatment groups.

Of F1 animals selected to produce the F2 generation, no test substance related mortality of clinical signs of toxicity were noted. Clinical signs were of low incidence and sporadically distributed among treatment groups and were, therefore, not considered test substance related. There were no toxicologically meaningful differences in body weight or body weight gains during the growth phase, however, mean body weight gain was significantly lower in the 1.0 and 5.0 mg/kg bw/day treatment groups during lactation days 14-21. There were no toxicologically meaningful differences in food consumption. No statistically significant differences were found in copulation or fertility indices, estrous cycle determinations, precoital intervals, or gestation lengths. There were no statistically significant differences in mean implantation scar counts, mean number of live pups on lactation day 0, or mean post-implantation loss. Statistically significant differences in organ weights included decreased absolute pituitary weight in 1.0 mg/kg bw/day males, increased relative adrenal weight and decreased relative liver weight in 5.0 and 10.0 mg/kg bw/day males, and decreased relative liver weight in 2.5 and 10.0 mg/kg bw/day females. There were no toxicologically meaningful differences in sperm parameters of 10 mg/kg bw/day males. No test substance related microscopic histopathological changes were noted.

F2 generation: No test substance related clinical signs of toxicity were noted. There were no statistically significant differences in body weights during lactation. Gross necropsy observations included atelectasis and absence of milk in the stomach. Other necropsy findings were of low incidence and sporadically distributed among treatment groups.

Key result

Dose descriptor:

NOAEL

Effect level:

5 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reduction in number of live offspring

Remarks on result:

other: equivalent to 1.1 mg Ni/ kg bw

Key result

Abnormalities:

effects observed, treatment-related

Key result

Developmental effects observed:

yes

Lowest effective dose / conc.:

10 mg/kg bw/day (nominal)

Treatment related:

yes

Relation to maternal toxicity:

developmental effects in the absence of maternal toxicity effects

Dose response relationship:

yes

Relevant for humans:

not specified

The study was conducted to evaluate the potential effects of the test substance administered to Sprague-Dawley rats in a two-generation study. Oral (gavage) administration of nickel sulfate hexahydrate at dose levels up to 10 mg/kg/day (2.2 mg Ni/kg) had no effect on F0 or F1 survival, growth, mating behaviour, fertility, gestation, parturition, or lactation.  There was no test substance related mortality or clinical signs of toxicity in F0 and F1 rats or their offspring.  Pup viability and growth was not affected.  There were no toxicologically meaningful differences in estrous cycling, sperm parameters, copulation, and fertility indices, precoital intervals, gestation lengths, gross necropsy findings, or the onset of sexual maturation in F1 rats.  Histopathological examinations did not reveal any test article-related changes in the liver, reproductive organs, or other tissues examined.  Statistically significant reductions in absolute and/or relative liver weights in F0 males at 10 mg/kg/day and in F1 males at 5.0 and 10.0 mg/kg/day were not regarded as toxicologically  significant. Relative liver weight values were less than 10% different  from the respective control values. The developmental NOAEL (2.2 mg Ni/kg BW/day) was based on the absence of a significant increase in perinatal lethality at the highest exposure used in the study.

Conclusions:

Based on the study results the NOAEL for teratogenicity was determined to be 5 mg/kg bw/d, the NOAEL for maternal effects was found to be 10 mg/kg bw/d.

Reference 2

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The test item was administered orally on body weight base during the organogenesis period from days 6 to 13 of the gestation period and developmental endpoints were assessed on gestational day 18.

GLP compliance:

not specified

Limit test:

no

Specific details on test material used for the study:

Nickel chloride hexahydrate procured from Hi-Media Laboratories Pvt. Ltd., Mumbai, (Purity: 97.0%) was used for the study.

Species:

mouse

Strain:

Swiss

Details on test animals or test system and environmental conditions:

Swiss albino mice (7–9 weeks of age, 24 ± 2 gm) selected from an inbred colony were maintained on standard mice feed (Aashirwad Ltd., Chandigarh) and tap water ad libitum.

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

Animals were divided into four groups of ten mice each. Group I was given tap water and served as a control, while groups II, III, and IV were given 46.125, 92.25, and 184.5 mg Ni/kg bw/d as NiCl2 ⋅6H2O orally from days 6 to 13 of gestation, that is, organogenetic period. The doses were selected below LD50, that is, 369 mg Ni/kg bw Dams were sacrificed by cervical dislocation on day 18 of gestation, and uteri of all the sacrificed dams were examined.

Analytical verification of doses or concentrations:

no

Details on mating procedure:

Female and male mice were housed formating in the ratio of 3 : 1 and examined every morning for vaginal plug. The day on which vaginal plug were detected was considered as day zero of pregnancy.

Duration of treatment / exposure:

From days 6 to 13 of gestation

Frequency of treatment:

daily

Duration of test:

until gestational day 18

Dose / conc.:

0 mg/kg bw/day

Remarks:

group I

Dose / conc.:

46.125 other: mg Ni/kg bw/day

Remarks:

group II

Dose / conc.:

92.25 other: mg Ni/kg bw/day

Remarks:

group III

Dose / conc.:

184.5 other: mg Ni/kg bw/day

Remarks:

group IV

No. of animals per sex per dose:

10 females per dose

Control animals:

yes, concurrent vehicle

Maternal examinations:

Diet consumption, water intake and body weight of all the groups were recorded daily.

Ovaries and uterine content:

The uteri of all the sacrificed dams were examined.

Fetal examinations:

The implant sites and live fetuses per dam were counted, and the conceptus at each site was classified as being alive, resorbed, or dead. The live fetuses were sexed, weighed, and examined for morphological alterations. Randomly selected 75% of fetuses were fixed in 95% alcohol for double staining (alizarin red S and alcian blue) to observe the skeletal anomalies, and the remaining fetuses were fixed in Bouin’s fixative to study the brain.

Statistics:

The statistical analysis of the data was evaluated by using the Microsoft Office Excel 2003 software, and the significance of the data was determined either by using one way analysis of variance (ANOVA) or one way Mann-Whitney U test. The levels of significance were p < 0.05 (almost significant) and p < 0.01 (significant).

Indices:

Average number of implant sites/dam, Average number of live fetuses/dam

Historical control data:

none reported

Clinical signs:

no effects observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Body weight decreased significantly (𝑃 < 0.01) after 92.25 and 184.5 mg Ni/kg bw/d.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

The pregnant females administered with the test item during organogenetic
period revealed an almost significant (𝑃 < 0.05) decrease in diet consumption after 92.25 mg Ni/kg bw /d. However, after 184.5 mg Ni/kg bw/d, the decrease was significant (𝑃 < 0.01). A similar pattern of decrease was observed concerning the intake of water.

Number of abortions:

not specified

Pre- and post-implantation loss:

effects observed, treatment-related

Description (incidence and severity):

The average implant sites per dam decreased after 92.25 and 184.5 mg Ni/kg bw/d when compared with the control group. At 184.5 mg Ni/kg bw/d dose level, the incidence of postimplantation death (35.29%) was evident. In groups II and III, the loss was 4.16 % and 9.09 %, respectively.

Early or late resorptions:

effects observed, treatment-related

Description (incidence and severity):

In the highest exposure group there was a concomitant rise in the percentage of resorbed, dead, and macerated fetuses.

Dead fetuses:

effects observed, treatment-related

Description (incidence and severity):

In the highest exposure group there was a concomitant rise in the percentage of resorbed, dead, and macerated fetuses.

Details on maternal toxic effects:

Maternal toxic effects: yes

Details on maternal toxic effects:
The pregnant females administered with the test material during organogenetic period revealed an almost significant (p < 0.05) decrease in diet consumption after 92.25 mg Ni/kg bw/d. However, after 184.5 mg Ni/kg bw/d, the decrease was significant (p < 0.01). Similar pattern of decrease was evident with the intake of water. Maternal weight decreased significantly (p < 0.01) after 92.25 and 184.5 mg Ni/kg bw/d.

Dose descriptor:

LOAEL

Effect level:

184.5 other: mg Ni/kg bw/d

Basis for effect level:

body weight and weight gain

food consumption and compound intake

water consumption and compound intake

Key result

Dose descriptor:

NOAEL

Effect level:

92.25 other: mg Ni/kg bw/d

Based on:

other: Ni

Basis for effect level:

other: maternal toxic effects

Key result

Abnormalities:

no effects observed

Fetal body weight changes:

effects observed, treatment-related

Description (incidence and severity):

The average fetal weight was reduced (𝑃 < 0.01) in a dose-dependent manner.

Reduction in number of live offspring:

effects observed, treatment-related

Description (incidence and severity):

In the highest exposure group there was a concomitant rise in the percentage of dead fetuses.

Changes in sex ratio:

no effects observed

External malformations:

effects observed, treatment-related

Description (incidence and severity):

Fetuses with macroscopic anomalies such as open eye lids (10% and 12.50% in groups III and IV), club foot (6.25% in group IV), and umbilical hernia (5% and 6.25% in groups III and IV) were evident. Ophthalmic anomalies, namely, microphthalmia (5%, 5%, and 6.25% in all the treated groups) and exophthalmia (5% in group III) were observed. The occurrence of hydrocephaly in groups III and IV was 5% and 12.50%, and microcephaly in group III was 5%, respectively.

Skeletal malformations:

effects observed, treatment-related

Description (incidence and severity):

The fetal skeletons showed numerous anomalies such as reduced ossification of nasal, frontal, parietal, intraparietal, and supra-occipital bones of skull, absence or gap between the ribs, reduced or fused sternebrae, reduced/absence/displaced vertebral centra in thoracic and lumbar regions, reduced/absence of caudal vertebrae, reduced pelvic elements, and absence of carpals, metacarpals, tarsals, metatarsals, and phalanges. The percentage of skeletal anomalies was found to be dose dependent.

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
The average implant sites per dam decreased after 92.25 and 184.5 mg Ni/kg bw/d. when compared with the control group. Average number of live fetuses/dam were significantly reduced (p < 0.01) in group IV (184.5 mg Ni/kg bw/d). Further, there was a concomitant rise in the percentage of resorbed, dead, and macerated fetuses in group IV. However, in groups II and III, the dead and macerated fetuses were not observed. At 184.5 mg Ni/kg bw/d dose level, the incidence of postimplantation death (35.29%) was evident. No change was evident in the sex ratio (M: F) after oral administration of Ni at all the three dose levels. The average fetal weight significantly reduced (p < 0.01) in a dose-dependent manner. The placental weight decreased nonsignificantly in all the treated groups.

Fetuses with macroscopic anomalies such as open eye lids (10% and 12.50% in groups III and IV), club foot (6.25% in group IV), and umbilical hernia (5% and 6.25% in groups III and IV) were evident. Ophthalmic anomalies, namely, microphthalmia (5%, 5%, and 6.25% in all the treated groups) and exophthalmia (5% in group III) were observed. The occurrence of hydrocephaly in groups III and IV was 5% and 12.50%, and microcephaly in group III was 5%, respectively. No gross anomalies were seen in group II). The double stained (alizarin red S and alcian blue) skeleton of fetuses showed numerous anomalies such as reduced ossification of nasal, frontal, parietal, intraparietal, and supra-occipital bones of skull, absence or gap between the ribs, reduced or fused sternebrae, reduced/absence/displaced vertebral centra in thoracic and lumbar regions, reduced/ absence of caudal vertebrae, reduced pelvic elements, and absence of carpals, metacarpals, tarsals, metatarsals, and phalanges. The percentage of skeletal anomalies was found to be dose dependent.

Key result

Dose descriptor:

NOAEL

Effect level:

92.25 other: mg Ni/kg bw/d

Based on:

other: Ni

Sex:

male/female

Basis for effect level:

other: overall effects

Key result

Abnormalities:

effects observed, treatment-related

Localisation:

other: internal (skeletal) and external macroscopic anomalies

Description (incidence and severity):

anomalies occured in a dose-dependent manner

Key result

Developmental effects observed:

yes

Lowest effective dose / conc.:

184.5 other: mg Ni /kg bw/d

Treatment related:

yes

Relation to maternal toxicity:

developmental effects occurring together with maternal toxicity effects, but not as a secondary non-specific consequence of maternal toxicity effects

Conclusions:

The NOAEL for maternal toxicity as well as developmental effects was determined to be 92.25 mg Ni/kg bw/d.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

92.25 mg/kg bw/day

Study duration:

subacute

Species:

mouse

Quality of whole database:

Well documented publication

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

Two-generation reproductive toxicity study with CAS 10101-97-7: please refer to the field "additonal information" in the "effects on fertility" section above.

Developmental toxicity

Read across to CAS 7791-20-0, mouse:

The study evaluates potential hazardous of nickel (as NiCl2⋅6H2O) to Swiss albino mice fetus. Ni was administered orally on body weight base from days 6 to 13 of gestation period. Based on LD50, Ni doses (46.125, 92.25, and 184.5) mg Ni/kg bw/d were used. On day 18 of gestation, uteri of the sacrificed dams were examined. A dose-dependent decrease in the body weights of the pregnant females and the fetuses was observed. The number of implant sites and placental weight at all the three dose levels was lower compared with their respective control groups. The average number of live fetuses/dam was reduced significantly (p<0.01) at 184.5 mg Ni/kg bw/d with concomitant increase in the percentage of postimplantation death and percentage of resorbed, macerated, and dead fetuses, respectively. Exposure increased the fetal malformations, namely, hydrocephaly, open eyelids, microphthalmia, exophthalmia, club foot, umbilical hernia, and skeletal anomalies. Reduced ossification of nasal, frontal, parietal, intraparietal, and supraoccipital bones, absence/gap between the ribs, reduced/fused sternebrae, vertebral centra, and caudal vertebrae, reduced pelvic elements, absence of carpals, metacarpals, tarsals, metatarsals, and phalanges were distinct. Based on the available data the NOAEL for maternal toxicity as well as developmental effects was determined to be 92.25 mg Ni/kg bw/d.

Conclusion

Based on the teratogenic effects observed with the read across substance, the target substance is also considered to be classified for reproductive toxicity into category Repr. 1B and labelled with H360 (May damage fertility or the unborn child) for developmental effects.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available data were considered reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. Based on the results, the target and source substances classified for reproductive toxicity into category Repr. 1B and labelled with H360 (May damage fertility or the unborn child) for developmental effects, as amended for the fifteenth time in Regulation (EU) No 2020/1182.