Barium fluoride

Toxicity to reproduction

Administrative data

Endpoint:

fertility, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study well documented, meets generally accepted scientific principles, acceptable for assessment. Data and Rating according to the SIDS 2005 on barium cabonate. Deviances when comparing to OECD421: dosing only prior to mating, no individual animal data/tables provided, histopathologic examination, data on food consumption only provided for core study animals, no humidity, sex of pups, and data on stability of test substance in vehicle given. Only the average results of the controls and the high dose groups of each species were available.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure in accordance with generally accepted scientific standard and described in sufficient detail. Data and rating according to the SIDS 2005 on barium carbonate.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Barium chloride dihydrate (BaCl2 * 2H2O) was given for 92 days to Fischer 344/N rats in their drinking water at levels of 0, 125, 500, 1000, 2000 and 4000 ppm.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Simonsen Laboratories (Gilroy, CA)
- Age at study initiation: 32 days
- Housing: The animals were housed five per cage in drawer type polycarbonate cages. The shelves supporting the cages were covered with filter sheets. The bedding was (Ab-Sorb-Dri, Lab Products, Rochelle Park, NJ)
- Diet (ad libitum): NIH-07 pellets (Ziegler Brothers, Gardners, PA)
- Water (ad libitum): dosed with test substance or undosed water
-Quarantine period: 10 to 11 days after arrival, and representatives were necropsied to verify that they were grossly free of disease.

ENVIRONMENTAL CONDITIONS
- Temperature: 21 to 24 °C
- Air changes (per hr): Filtered fresh air (13.5 room vol/hr) was supplied directly and removed from the animal room.
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.

Route of administration:

oral: drinking water

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:Solutions were made weekly in 19-liter quanities by dissolving weighed portions of the chemical in glass-distilled water.
No further information on details on oral exposure was stated.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Dosage analyses were performed on all levels before and after use, and at the beginning and midway through the test period, indicated that the concentrations were within 1 to 6 % of the theroretical concentrations.

Duration of treatment / exposure:

92 consecutive days

Frequency of treatment:

Dosed water on an ad libitum basis during treatment.

Remarks:

Doses / Concentrations:
4000 ppm BaCl2 * 2H20
Basis:
nominal in water

Remarks:

Doses / Concentrations:
2000 ppm BaCl2 * 2H20
Basis:
nominal in water

Remarks:

Doses / Concentrations:
1000 ppm BaCl2 * 2H20
Basis:
nominal in water

Remarks:

Doses / Concentrations:
500 ppm BaCl2 * 2H20
Basis:
nominal in water

Remarks:

Doses / Concentrations:
125 ppm BaCl2 * 2H20
Basis:
nominal in water

No. of animals per sex per dose:

Groups of 10 per dose level after weight-sorting them by sex.

Control animals:

yes, concurrent vehicle

Positive control:

No data

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- twice daily for clinical signs

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

WATER CONSUMPTION (if drinking water study): Yes
- Time schedule for examinations: twice weekly

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: no data
- Animals fasted: No data
- How many animals: 7-10 animals
- Parameters checked in table: serum sodium potassium, calcium, phosphorus

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: on each animal at 0, 45 to 48, and 91 days of exposure
- Dose groups that were examined: all
- Battery of functions tested: undifferentiated motor activity, forelimb and hindlimp grip strengths, thermal sensitivity to a 55°C water bath, startle response to acoustic and air-puff stimuli, and hindlimb foot splay.

DETAILED CLINICAL OBSERVATIONS: No data

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: No data

URINALYSIS: No data

No further information on observations and examinations performed and frequency was stated.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
All animals were examined for gross lesions. The brain, liver, right kidney, lung, thymus, right testis, heart, and adrenals were weighed before fixation
HISTOPATHOLOGY: Yes
Complete histologic exams were performed on 30 or more tissues from animals of 4000 ppm and the control groups. Because histopathological changes were observed in several tissues (thymus, spleen, kidneys, and lymph nodes) from rats in the 4000 ppm group, these tissues were examined from the lower dose animals to determine a no-effect level.
No further information on sacrifice and pathology were stated.

Other examinations:

none

Statistics:

Each parameter for which individual values were available was subjected to a linaer lesat squares regression over the dose levels and the direction of the slope and the p value indicating the significance of the deviation of the slope from 0 was determined. Group means and standard deviation or standard errors were calcualted for continuous variables. the multiple comparison procedure of Dunnett (1955) was employed for pairwise comparisons of these variables between dosed groups and controls. Fisher's exact test was used to make pairwise comparisons of discrete variables between dosed groups and controls and the Cochran-Armitage test was used to assess the significance of dose-related trends (Armitage, 1971; Gart et al., 1979). Temporal and dose-related variations were evaluated using a repeated measures analysis of variance (Winter, 1971). When a collection of measurements were made on each animal, a multivariate analysis of variance (Morrison, 1976) was used to test for the simultaneous equality of measurements across dose levels.

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

effects observed, treatment-related

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not specified

Behaviour (functional findings):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not specified

Details on results:

CLINICAL SIGNS AND MORTALITY
Three of 10 male and 1 of 10 female rats in the 4000 ppm groups died during the last week of the study. No clinical signs were oberved.

BODY WEIGHT AND WEIGHT GAIN
Body weights of both sexes in the 4000 ppm groups were significantly (p< 0.05) lower than the controls. Signs of weight loss were observed.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study)
Rats in the 4000 ppm groups consumed 70 % of water consumed by controls. It is not clear whether the effcets are toxicity related or due to palatobility

CLINICAL CHEMISTRY
In the male rats, there was a significant elevation in phosphorous in the 1000, 2000, and 4000 ppm groups compared with the controls. In the female rats, a significant elevation in phosphorous was seen in the 500, 1000, 2000, and 4000 ppm groups. The biological significance of the changes in females are regarded as marginal due to lower than expected control values.

ORGAN WEIGHTS
The liver weights of the rats received 4000 ppm were depressed. The absolute kidney weights were elevated in the 1000 and 4000 ppm females, and the relative kidney weights were elevated in 4000 ppm to males and 1000 ppm or greater to females. These changes were variable and were probably related to treatment-depressed body weights rather than kidney toxicity. Tymus weights were depressed in the high dose female rats.

GROSS PATHOLOGY/HISTOPATHOLOGY
The kidney changes in rats were limited to few foci of dilated tubules in the outer medulla or meduallary rays. Tubular cell regression, casts, and crystals were not a feature of the renal lesions in rats. Lymphoid depletion was also present in the spleen and thymus of the early death rats.
There were no treatment-related histopathologic effects in the brain or other tissues of rats.

NEUROBEHAVIOUR
Compared to their controls, rats exposed to 2000 ppm BaCl2 or lower did not show any consistent changes in behavoioural indices (motor activity, fore- and hindlimp grip strength, and thermal sensitivity). Marginal although significant behavioural effects were noted at the 4000 ppm level in rats. these changes were probably a result of the overall BaCl2 toxicity observed at the 4000 ppm dose level.The behavioural effects observed at the 4000 ppm are as follows: Decreased undifferentiated motor acivity in female rats on day 91. No significant or dose-related effects were seen in the startle response to acoustic and air-puff stimuli or the hindlimb foot splay.

Dose descriptor:

NOAEL

Effect level:

2 000 ppm

Sex:

male/female

Basis for effect level:

other: see remark

Dose descriptor:

NOAEL

Effect level:

80.9 mg/kg bw/day (nominal)

Sex:

female

Basis for effect level:

other: calculated as Ba2+

Dose descriptor:

NOAEL

Effect level:

61.1 mg/kg bw/day (nominal)

Sex:

male

Basis for effect level:

other: calculated as Ba2+

Critical effects observed:

not specified

Conclusions:

The NOAEL of Barium chloride is 2000 ppm (corresponding to 61.1 and 80.9 mg Ba/kg bw/day for male and female rats respectively)

Executive summary:

Barium chloride dihydrate was administered for 92 days to Fischer 344/N rats in drinking water at levels of 0, 125, 500, 1000, 2000, and 4000 ppm. Mortality was observed in 3/10 males and 1/10 females in the 4000 ppm group. Depressed body weight gains, elevated phosphorus levels and chemically related lesions in the kidney and lympoid tissue at the highest dose level of 4000 pm. At 4000 ppm, motor activity, grip strength, and thermal sensitivity were marginally affected. These effects were probably secondary changes resulting from barium chloride toxicity observed at this dose level. Individual effects observed at 2000 ppm barium chloride in drinking water (corresponding to the final barium dose of 61.1 and 80.9 mg Ba/kg bw/day to male and female rats respectively) were regarded as not treatment-related and this dose levels represents the NOAEL.

Data source

Reference

Reference Type:

publication

Title:

Subchronic toxicity of barium chloride dihydrate administered to rats and mice in the drinking water.

Author:

Dietz, D.D.; et al.

Year:

1992

Bibliographic source:

Fund. Appl. Tox. 19, 527-537

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

In parallel with a subchronic toxicity core study, a premating study was performed with separate groups of rats and mice. Premating exposure period with Barium chloride dihydrate was 60 days for males and 30 days for females.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

barium(2+) dichloride dihydrate

EC Number:

600-412-6

Cas Number:

10326-27-9

Molecular formula:

BaCl2.2(H2O)

IUPAC Name:

barium(2+) dichloride dihydrate

Test material form:

solid: crystalline

Details on test material:

- Name of test material (as cited in study report): Barium chloride dihydrate
- EC number: 233-788-1
- Molecular formula (if other than submission substance): BaCl2 * 2H2O
- Molecular weight (if other than submission substance): 226.3 g (calculated from molecular formula)
- Smiles notation (if other than submission substance):
- InChl (if other than submission substance):
- Structural formula attached as image file (if other than submission substance): see Fig.
- Substance type: technical product
- Physical state: white, crystalline solid
- Analytical purity: 99.5 % (by EDTA titration)
- Lot/batch No.: 123120 (from Baker Chemical Co., Phillipsburg, NJ)
- no further significant details stated

Test animals

Species:

rat

Strain:

other: Fischer 334/N

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Simonson Laboratories, Gilroy, CA
- Age at study initiation: (P) 32 days
- Housing: five per cage in drawer-type polycarbonate cages (shelves covered with filter sheets, bedding, cages and water bottles were changed twice a week, feeders once a week, racks and filters every other week); after 60 days of exposure, the males were placed in individual cages and one female receiving the same dose level (but exposed for 30 days) was cohabited with the male. After mating the females were separated.
- Diet: NIH-o7 pellets (Ziegler Brothers, Gardners, PA)
- Water: ad libitum (dosed or undosed) for 92 consecutive days
- Acclimation period: 10 to 11 days (quarantined)


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 24 °C
- Air changes (per hr): 13.5 room vol.
- Photoperiod (hrs dark / hrs light): 12/12 (fluorescent lighting)

- no further significant details stated

Administration / exposure

Route of administration:

oral: drinking water

Type of inhalation exposure (if applicable):

other: not applicable

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

VEHICLE
- Solutions were made weekly in 19-liter quantities by dissolving weighed portions of the test substance in glass-distilled water.
- Concentration in vehicle: 0, 1000 and 4000 ppm
- no further significant details stated

Details on mating procedure:

- M/F ratio per cage: 1 male / 1 female rat
- Length of cohabitation: up to one week
- Proof of pregnancy:Examination of microscopic evidence of sperm in vaginal swab every morning
- When evidence of mating was found, the females was separated from the male.
- After mating determinations were made on the eighth day of cohabition and all remaining pairs were separated.
- No remating was performed although pregnancy rate was low.
- no further significant details stated

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyses were performed on all levels before and after use, and at the beginning and midway through the test period. The concentrations were within 1 to 6 % of the theoretical concentration. Method of analysis was not stated.

Duration of treatment / exposure:

Premating exposure period: 60 days for males and 30 days for females

Frequency of treatment:

continuous

Details on study schedule:

- no further significant details stated

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
1000 ppm BaCl2 x 2H2O
Basis:
nominal in water
calculated average dose: 63.5 mg Ba/kg bw/d to males and 64.5 mg Ba/kg bw/d to females

Doses / concentrations 2

Remarks:

Doses / Concentrations:
2000 ppm BaCl2 x 2H2O
Basis:
nominal in water
calculated average dose: 112 mg Ba/kg bw/d to males and 114 mg Ba/kg bw/d to females

Doses / concentrations 3

Remarks:

Doses / Concentrations:
4000 ppm BaCl2 x 2H2O
Basis:
nominal in water
calculated average dose: 201.5 mg Ba/kg bw/d to males and 179.5 mg Ba/kg bw/d to females

No. of animals per sex per dose:

20 male and 20 female rats

Control animals:

yes, concurrent vehicle

Details on study design:

- Other: No remating was performed due to restriction in the study dosing schedule/design.
- no further significant details stated

Positive control:

not required

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily


CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily


BODY WEIGHT: Yes
- Time schedule for examinations: weekly and females were weighed when evidence of mating was found an on the day of parturition.


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: twice weekly


OTHER:
- determination of pregnancy rates in dosed and control animals
- determination of average gestation period
- no further significant details stated

Oestrous cyclicity (parental animals):

- Evaluation of vaginal cytology was performed among treated and control groups.

Sperm parameters (parental animals):

Parameters examined in P male parental generations:
- An evaluation of sperm morphology, density, and motility and sperm count was performed among treated and control groups.
- no further significant details stated

Litter observations:

PARAMETERS EXAMINED
The following examinations were performed in F1 offspring:
- pups were examined at birth and day 5
- number of live litter, average litter size at day 0 and 5, pup survival to day 5, pup weight at birth and day 5, external abnormalities

GROSS EXAMINATION OF DEAD PUPS:
- yes, dead pups were examined for external abnormalities

- no further significant details stated

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: not stated
- Maternal animals: All surviving animals were terminated on days 96 and 97.

GROSS NECROPSY
- The vagina, cervix, oviducts, and ovaries were grossly examined and the implantation sites in the uteri were counted.
- The male reproductive organ weights (testis, epidimymal) was determined among treated and control groups.

HISTOPATHOLOGY / ORGAN WEIGHTS
- Complete histologic exams were performed in the parallel animal groups which were not used for reproductive and fertility assessment.

- no further significant details stated

Postmortem examinations (offspring):

- no data

Statistics:

Each parameter for which individual values were available was subjected to a linear least squares regression over the doselevels and the direction of the slope and the p value indicating the significance of the deviation of the slope from 0 was determined. Group means and standard deviations or standard errors were calculated for continuous variables. The multiple comparison procedure of Dunnett (1955) was used for comparison between dosed and control groups. Further, Fisher's extract test, the Cochran-Armitage test (Armitage, 1971; Gart et al., 1979) was used as well as repeated measures analysis of variance (WInter, 1971) and a multivariate analysis of variance (Morrison, 1976).

Reproductive indices:

- no significant details stated

Offspring viability indices:

- no significant details stated

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

not examined

Other effects:

effects observed, treatment-related

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
- one pregnant dam in the 4000 ppm group was terminated in a moribund state 21 days after mating


TEST SUBSTANCE INTAKE (PARENTAL ANIMALS)
- only determined for core study animals


REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
- There were no treatment-related effects of barium chloride dihydrate on vaginal cytology up to 4000 ppm.


REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS)
- There were no treatment-related effects of barium chloride dihydrate on epididymal sperm count, sperm motility, sperm morphology, up to 4000 ppm.


REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
- The pregnancy rates were below generally accepted norms: from 40 % in the controls and 65 % in the 4000 ppm group.
- All pregnant dams produced litters except for one in the 4000 ppm group, which was terminated
- The average gestation period of surviving dams was 22 to 22.5 days (in various groups).
- The number of implants per pregnant dam was marginally reduced in the 4000 ppm group compared with the controls (but without statistical significance at p<0.05)


ORGAN WEIGHTS (PARENTAL ANIMALS)
- no effect could be detected on testis or epididymal weight


GROSS PATHOLOGY (PARENTAL ANIMALS)
- necropsy of the terminated dam revealed 7 fetuses and one resorption site

- no further significant details stated

Effect levels (P0)

1

Dose descriptor:

NOAEL

Effect level:

4 000 ppm (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: fertility impairment

2

Dose descriptor:

NOAEL

Effect level:

201.5 mg/kg bw/day (nominal)

Based on:

other: barium

Sex:

male

Basis for effect level:

other: fertility impairment

3

Dose descriptor:

NOAEL

Effect level:

179.5 mg/kg bw/day (nominal)

Based on:

other: barium

Sex:

female

Basis for effect level:

other: fertility impairment

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

not specified

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Histopathological findings:

not examined

Details on results (F1)

VIABILITY (OFFSPRING)
- Pup survival to day 5 was 99 % or greater in all treatment groups.

CLINICAL SIGNS (OFFSPRING)
- No external abnormalities were observed in the rat offspring.

BODY WEIGHT (OFFSPRING)
- Rats receiving 4000 ppm exhibited significant although marginal reductions in pup weights at birth (5.20 +/- 0.06 g compared to 5.70 +/- 0.09 g); a comparision of pups weight on day 5 showed no significant differences. Weight gain was comparable among all pup groups.

OTHER
- The average litter size at birth and on postpartum day 5 was marginally reduced in the 4000 ppm group compared with the controls (but without statistical significance at p<0.05)

- no further significant details stated

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

4 000 ppm (nominal)

Based on:

test mat.

Sex:

not specified

Basis for effect level:

other: development toxicity, but the NOAEL is of limited value to evaluate the potential for barium to induce developmental effects

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Only the average results of the controls and the high dose groups of each species were available.

No-observed-adverse-effect level (NOAEL) for fertility impairmentwas 4,000ppm in rats. These NOAEL values correspond to average doses of 201.5 and 179.5 mg Ba/kg bw/d to male and and female rats, respectively.

A NOAEL on developmental toxicity of 4,000 ppm is also reported. However, the NOAEL is of limited value to evaluate the potential for barium to induce developmental effects. The reason for this limitation is based on the fact that the premating study design did not include exposure of female animals during the gestational period to barium chloride. Therefore, the premating study has to be considered as an inadequate study of developmental toxicity and cannot be used to determine the occurrence of developmental toxicity.

Applicant's summary and conclusion

Conclusions:

Taken together all data of this study, there are no indications of a substantial impairment of fertility in rats up to the highest dose tested. Thus, the NOAEL was 4000 ppm (to average doses of 201.5 and 179.5 mg Ba/kg bw/d to male and and female rats, respectively). No-observed-adverse-effect levels (NOAELs) on developmental toxicity for rats of 4000 ppm were derived from this study. However, this NOAEL is of limited value to evaluate the potential for barium to induce developmental effects because there was no exposure of the females during gestation.