Borate(1-), tris(acetato-.kappa.O)hydro-, sodium, (T-4)-

Toxicity to reproduction

Administrative data

Endpoint:

three-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented publication with the decomposition product boric acid which meets basic scientific principles

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Toxicologic studies on borax and boric acid

Author:

Weir, R.J. and Fisher, R.S.

Year:

1972

Bibliographic source:

Toxicology and Applied Pharmacology 23: 351 - 364

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1966

Report date:

1966

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: No guideline specified, but equivalent to the standard 3 generation study/multi-generation studies normally used at that time.

Principles of method if other than guideline:

No guideline specified, but equivalent to the standard 3 generation study/multi-generation studies normally used at that time.

GLP compliance:

no

Remarks:

prior to GLP

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Boric acid

EC Number:

233-139-2

EC Name:

Boric acid

Cas Number:

10043-35-3

Molecular formula:

BH3O3

IUPAC Name:

Boric acid

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Boric acid
- Analytical purity: > 99 %
- Supplier: U.S. Borax Research Corp., Anaheim, California

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Cesarean-derived from Charles River
- Weight at study initiation: 110 - 150 g
- Housing: Individidually housed
- Diet (e.g. ad libitum): Purina Laboratory Chow; ad libitum

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on mating procedure:

- M/F ratio per cage: 1:2
- Length of cohabitation: 21
- Breeding schedule:
24 h after birth, the F1 litters were reduced to a maximum of eight pups and discarded when they reached 21 days of age.
The parents in the control and two lower test groups were mated again. At the time of resulting weaning animals (F1B) 16 females and 8 males from the control and two test groups were chosen randomly and designated as the second parental generation (P2) for continuation of the reproduction study. These animals were bread to produce the F2A and F2B litters as before with the F2B litter becoming the P3 generation which was bread to produce the F3A and F3B litters.
Additional breeding of the high dose P1 with control males was performed to investigate whether the female reproductive system was affected.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

From premating for 14 days until scheduled necropsy of F3 generation

Frequency of treatment:

Daliy, ad libitum

Details on study schedule:

- Schedule:
F1a, F2a and F3a litters were sacrificed at weaning, while F1b and F2b litters raised and used for breeding.

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
34, 100, 336 mg/kg bw/d
Basis:
nominal in diet
Boric acid

Doses / concentrations 2

Remarks:

Doses / Concentrations:
670, 2000, 6700 ppm
Basis:
nominal in diet
Boric acid

Doses / concentrations 3

Remarks:

Doses / Concentrations:
5.9, 17.5, 58.8 mg/kg bw/d
Basis:
nominal in diet
Element Boron

No. of animals per sex per dose:

P1: 8 males and 16 females
P2: 8 males and 16 females
P3: 8 males and 16 females

Control animals:

yes, plain diet

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: weekly

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): weekly

Sperm parameters (parental animals):

Parameters examined in all male parental generations: analysis of sperm viability

Litter observations:

STANDARDISATION OF LITTERS
- Yes, maximum of 8 pups/litter; excess pups were killed and discarded.

PARAMETERS EXAMINED
The following parameters were examined in all offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities

Reproductive indices:

Fertility index = number of pregnancies/number of matings x 100
Lactation index = number weaned/numbe left to nurse x 100

Offspring viability indices:

Live birth index= number of pups born alive/number of pups born x 100

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

not specified

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not specified

Reproductive function: sperm measures:

effects observed, treatment-related

Reproductive performance:

effects observed, treatment-related

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
The high dose group (58.5 mgB/kg bw) males and females showed clinical signs of toxicity with rough fur, scaly tails, respiratory distress and inflamed eyelids.

REPRODUCTIVE FUNCTION:
When females of that group were mated with untreated males they had no offspring, indicating that the female reproduction was affected. A decreased ovulation in the majority of ovaries examined in that group was mentioned not to be sufficient to explain the observed infertility.
The high dose group P animals showed lack of viable sperm.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
There was no adverse effect on the reproduction in low and mid dose animals.

GROSS PATHOLOGY (PARENTAL ANIMALS)
No abnormalities were observed in the examined organs, except atrophied tested in the high dose males.

HISTOPATHOLOGY (PARENTAL ANIMALS)
Atrophied tested in the high dose males were seen.

Effect levels (P0)

1

Dose descriptor:

NOAEL

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Remarks:

Boric acid in diet

Sex:

male/female

Basis for effect level:

other: Arophied testes in all P1 males

2

Dose descriptor:

NOAEL

Effect level:

17.5 mg/kg bw/day (nominal)

Based on:

element

Remarks:

Boron in diet

Sex:

male/female

Basis for effect level:

other: atrophied testes in all P1 males

3

Dose descriptor:

LOAEL

Effect level:

336 mg/kg bw/day (nominal)

Based on:

test mat.

Remarks:

Boric acid in diet

Sex:

male/female

Basis for effect level:

other: histopathology;

4

Dose descriptor:

NOAEL

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Remarks:

Boric acid in diet

Sex:

male/female

Basis for effect level:

other: Atrophied testes in all P1 males

Remarks on result:

other: Generation: F1, F2 (migrated information)

5

Dose descriptor:

NOAEL

Effect level:

17.5 mg/kg bw/day (nominal)

Based on:

element

Remarks:

Boron in diet

Sex:

male/female

Basis for effect level:

other: Atrophied testes in all P1 males

Remarks on result:

other: Generation: F1, F2 (migrated information)

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

not examined

Sexual maturation:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

no effects observed

Histopathological findings:

not specified

Details on results (F1)

VIABILITY (OFFSPRING)
No change in litter size and livebirth index was noted in F1, F2 and F3 litters in low and high dose groups compared with control values.

BODY WEIGHT (OFFSPRING)
No change in body of pups in low and high dose groups weights was noted in F1, F2 and F3 litters in compared with control values.

GROSS PATHOLOGY (OFFSPRING)
No abnormalities were observed in the examined organs.

Effect levels (F1)

1

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Equivalent to 350 ppm of Boron in the diet.

2

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

17.5 mg/kg bw/day

Based on:

element

Sex:

male/female

Basis for effect level:

other: None

Results: F2 generation

Effect levels (F2)

1

Dose descriptor:

NOAEL

Generation:

F2

Effect level:

100 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Equivalent to 350 ppm of Boron in the diet.

2

Dose descriptor:

NOAEL

Generation:

F2

Effect level:

17.5 mg/kg bw/day

Based on:

element

Sex:

male/female

Basis for effect level:

other: No adverse effects in mid and low dose groups in any generation.

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Reproduction data:

	Control	Dietary level of Boric acid		Control	Dietary level of Boric acid
Index		34 mg/kg bw/d	100 mg/kg bw/d		34 mg/kg bw/d	100 mg/kg bw/d
	P1 - F1A			P1 - F1B
Fertility index	62.5	87.5	81.3	60	87.5	75
lactation index	56.3*	96.2	70.3*	58.8	85.6*	80.0*
Live birth index	98.4	96	97.2	99.1	99.4	100
	P2 - F2A			P2 - F2B
Fertility index		81.3	93.8	80	93.8	93.8
lactation index		48.3	79.2*	92.1	81	98
Live birth index		97.8	100	98.6	99.4	97.9
	P3 - F3A			P3 - F3B
Fertility index	68.8	100	87.5	68.8	93.8	93.8
lactation index	91.5	82.5	86.5	89.7	86.7	87.9
Live birth index	100	99.5	97.9	100	99	98.8

* significantly higher than control

Applicant's summary and conclusion

Conclusions:

Based on the sterility in the highest dose group, the NOAEL for reproduction was found to be 100 mg/kg bw/d Boric acid in diet corresponding to 17.5 mg/kg bw Boron.

Executive summary:

In a three generation study in rats groups of 8 males and 16 females were treated with boric acid equivalent to 0, 5.9, 17.5 and 58.8 mg boron/kg bw/day. The high dose P1-generation failed to produce litter. Also when females of that group were mated with untreated males they had no offspring, indicating that the female reproduction was affected. A decreased ovulation in the majority of ovaries examined in that group was mentioned not to be sufficient to explain the observed infertility since only ovaries of high dosed females were examined. However, gross necropsy revealed atrophied testes in all P1 males at 58.8 mg boron/kg bw/day. Based on the sterility in the highest dose group, the NOAEL for reproduction was found to be 100 mg/kg bw/d Boric acid in diet corresponding to 17.5 mg/kg bw Boron.