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EC number: 231-891-6 | CAS number: 7775-19-1
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
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Carcinogenicity
Administrative data
Description of key information
A 2-year carcinogenicity study of boric acid (NTP, 1987) equivalent to OECD Guideline 451 was carried out in mice. The study showed that boric acid was non-oncogenic by the oral route. The NOAEL is equivalent to 201 mg B/kg bw/day (corresponding to a NOAEL of 1223 mg/kg bw/day for sodium metaborate (anhydrous), 1892.6 mg/kg bw/day for sodium metaborate dihydrate and 2563.8 mg/kg bw/day for sodium metaborate tetrahydrate).
Key value for chemical safety assessment
Carcinogenicity: via oral route
Link to relevant study records
- Endpoint:
- carcinogenicity: oral
- 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: Comparable to guideline study with acceptable restrictions
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 451 (Carcinogenicity Studies)
- Deviations:
- yes
- Remarks:
- The full report is not published by the NTP. Sufficient detail is available to make an assessment of chronic toxicity and carcinogenesis although limited details are available and all individual animal data are not available.
- GLP compliance:
- yes
- Species:
- mouse
- Strain:
- B6C3F1
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Frederick Cancer Research Center, Frederick MD, USA
- Age at study initiation: 7 weeks
- Weight at study initiation: Males 21.6-21.8 g; females 17.1-17.7 g - Route of administration:
- oral: feed
- Vehicle:
- unchanged (no vehicle)
- Details on exposure:
- In food at 0, 2500, 5000 ppm boric acid equivalent to 0, 446 and 1150 mg/kg bw/d food consumption per day ad libitum
- Analytical verification of doses or concentrations:
- not specified
- Details on analytical verification of doses or concentrations:
- No data
- Duration of treatment / exposure:
- 103 weeks
- Frequency of treatment:
- Daily; food available ad libitum
- Post exposure period:
- No data
- Remarks:
- Doses / Concentrations:
0, 446, or 1150 mg/kg bw/d In a bioassay fifty B6C3F, mice per group and sex were administered 0, 2,500 and 5,000 ppm boric acid in the diet for 103 weeks (NTP, 1987). The average amount of boric acid consumed daily was approximately 400-500 mg/kg low
Basis:
actual ingested - No. of animals per sex per dose:
- 50/sex/group
- Control animals:
- yes, plain diet
- Details on study design:
- No data
- Positive control:
- No data
- Observations and examinations performed and frequency:
- CAGE SIDE OBSERVATIONS: Yes
DETAILED CLINICAL OBSERVATIONS: Yes
BODY WEIGHT: Yes
FOOD CONSUMPTION AND COMPOUND INTAKE: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: 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 - Sacrifice and pathology:
- GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes - Other examinations:
- No data
- Statistics:
- No data
- Clinical signs:
- not specified
- Mortality:
- not specified
- Body weight and weight changes:
- not specified
- Food consumption and compound intake (if feeding study):
- not specified
- Food efficiency:
- not examined
- Water consumption and compound intake (if drinking water study):
- not examined
- Ophthalmological findings:
- not examined
- Haematological findings:
- not examined
- Clinical biochemistry findings:
- not examined
- Urinalysis findings:
- not examined
- Behaviour (functional findings):
- not examined
- Organ weight findings including organ / body weight ratios:
- not specified
- Gross pathological findings:
- effects observed, treatment-related
- Histopathological findings: non-neoplastic:
- not specified
- Histopathological findings: neoplastic:
- not specified
- Details on results:
- CLINICAL SIGNS AND MORTALITY
Reduced survival in all dose groups including control. In the males the final survival was 82 % , 64 % and 44 % with increasing dosage which may have reduced the sensitivity of the study. Final survival in females was 66 %, 66 % and 74 % for 0, 446, and 1150 mg/kg bw/d respectively, which was adequate for assessment of the study. Bodyweight gain reduced during the first year, mean final bodyweights were 75 and 13 % below control values for exposed males and 7 % and 20 % below control values for females. No chemically related clinical signs were reported.
An increase of testicular atrophy was seen at the high dose (3/49 control, 6/50 low dose and 27/47 high dose) and interstitial cell hyperplasia (0/49, 0/50, 7/47) in male mice. There was variable loss of spermatogenia, and and various stages of spermatogenesis from the seminiferous tubles. There were no treatment related increase in tumours.
Survival in high dose males was significantly lower than controls after week 63, and in the low dose males after week 84 except for week 101. No significant differences in females. There was a dose related reduction in bodyweight gain after week 30 in both males and females.
BODY WEIGHT AND WEIGHT GAIN
Bodyweight gain reduced during first year; mean final bodyweights were 7 % and 13 % below control values for exposed males and 7 % and 20 % below control values for females.
FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
The average daily consumption in low and high dose males was 118 % and 160 % of controls, and in low and high dose females was 118 % and 136 % of controls. These were thought to be probably related to spillage caused by reduced palatability.
HISTOPATHOLOGY:
An increase of testicular atrophy was seen at the high dose (3/49 control, 6/50 low dose and 27/47 high dose) and interstitial cell hyperplasia (0/49, 0/50, 7/47) in male mice. There was variable loss of spermatogenia, and various stages of spermatogenesis from the seminiferous tubules. No evidence of carcinogenicity was found. - Relevance of carcinogenic effects / potential:
- Reduced survival in all dose groups including control. In the males the final survival was 82 %, 64 % and 44 % with increasing dosage which may have reduced the sensitivity of the study. Final survival in females was 66 %, 66 % and 74 % for 0, 446, and 1150 mg/kg w/d respectively, which was adequate for assessment of the study. Bodyweight gain reduced during the first year, mean final bodyweights were 75 and 13 % below control values for exposed males and 7 % and 20 % below control values for females. No chemically related clinical signs were reported. An increase of testicular atrophy was seen at the high dose (3/49 control, 6/50 low dose and 27/47 high dose) and interstitial cell hyperplasia (0/49, 0/50, 7/47) in male mice. There was variable loss of spermatogenia, and various stages of spermatogenesis from the seminiferous tubles. There were no treatment related increase in tumours.
- Dose descriptor:
- NOEL
- Effect level:
- > 5 000 ppm (nominal)
- Based on:
- test mat.
- Sex:
- not specified
- Basis for effect level:
- other:
- Conclusions:
- An OECD 451 study in B6C3F1 mice consisting of 50 per sex per group treated in diet for 103 weeks with 0, 2500 or 5000 ppm boric acid showed no evidence of carcinogenicity (NTP classification meaning no chemically related increase in benign or malignant neoplasms).
Reference
Parameter |
Control data |
Low dose |
Medium dose |
High dose |
Dose- response + / |
|||||||
Historical |
Study |
|||||||||||
m |
f |
m |
f |
m |
f |
m |
f |
m |
f |
m |
f |
|
Number of animals examined |
|
|
50 |
50 |
50 |
50 |
- |
- |
50 |
50 |
|
|
Mortality |
|
|
9 |
18 |
20 |
17 |
|
|
28 |
13 |
Y |
N |
clinical signs |
|
|
0 |
0 |
0 |
0 |
|
|
0 |
0 |
|
|
body weight gain |
|
|
20.3g |
27.2g |
17.5g |
24.1g |
|
|
14.7g |
18.8g |
Y |
Y |
food consumption |
|
|
na |
na |
na |
na |
|
|
na |
na |
|
|
clinical chemistry |
|
|
Not done |
|
|
|
|
|
|
|
|
|
haematology |
|
|
not done |
|
|
|
|
|
|
|
|
|
urinalysis |
|
|
not done |
|
|
|
|
|
|
|
|
|
Overall tumour incidence: |
|
|
31 |
25 |
37 |
27 |
|
|
23 |
26 |
N |
N |
No. of animals with neoplasms |
|
|
31 |
25 |
37 |
27 |
|
|
23 |
26 |
N |
N |
No. of animals with benign neoplasms |
|
|
23 |
8 |
22 |
11 |
|
|
16 |
14 |
N |
N |
No. of animals with malignant neoplasms |
|
|
13 |
20 |
23 |
15 |
|
|
11 |
17 |
N |
N |
No. of animals with > 1 neoplasm |
|
|
|
|
|
|
|
|
|
|
|
|
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- NOAEL
- 1 223 mg/kg bw/day
- Study duration:
- chronic
- Species:
- rat
- Quality of whole database:
- Comparable to guideline study with acceptable restrictions.
Carcinogenicity: via inhalation route
Endpoint conclusion
- Endpoint conclusion:
- no study available
Carcinogenicity: via dermal route
Endpoint conclusion
- Endpoint conclusion:
- no study available
Justification for classification or non-classification
No classification according to Regulation (EC) No 1272/2008 is required for sodium metaborate regarding carcinogenicity as all results for boric acid were negative.
Additional information
In long term feeding studies on boric acid and disodium tetraborate decahydrate in both rats and mice, no carcinogenic effects were observed (Weir, 1966a, b; Weir and Fisher, 1972).
An OECD 451 equivalent study in B6C3F1 mice consisting of 50 per sex per group treated in diet for 103 weeks with 0, 2500 or 5000 ppm boric acid showed no evidence of carcinogenicity (NTP classification meaning no chemically related increase in benign or malignant neoplasms).
Based on the mouse NTP-study (1987) boric acid is not regarded carcinogenic. Although not carried out according to modern standards, nor to GLP, the 2-year studies in rats and dogs support this finding. While in the 2-year rat studies, only 10 animals/sex of the control and high-dose group were macroscopically and histologically examined, only 1-2 animals/sex/dose/time were examined in the 2-year studies in dogs, which limits the conclusions that can be derived from these studies. However, they were well performed and reported and are adequate to evaluate the carcinogenicity of boric acid and sodium borates. It can be concluded that boric acid and sodium borates are not carcinogenic and there is no concern for carcinogenic effects in humans.
Since all the borates will exist as undissociated boric acid under physiological and environmental conditions, the toxicology of all these simple borates is similar on an equivalent boric acid basis or boron basis. Therefore, data for boric acid and disodium tetraborate decahydrate can be read across to the other borates for toxicological effects.
Please also refer to the read-across statement attached to section 13.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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